CAR SECTION 9 – SERIES M, PART I, Meteorological Service for Air Navigation

GOVERNMENT OF INDIA OFFICE OF DIRECTOR GENERAL OF CIVIL AVIATION TECHNICAL CENTRE, OPPOSITE SAFDARJANG AIRPORT, NEW DELHI CIVIL AVIATION REQUIREMENTS SECTION 9 – AIR SPACE AND AIR NAVIGATION SERIVCES STANDARDS SERIES M, PART I ISSUE III, 24TH MARCH 2024 EFFECTIVE: OCT 2025 F. No DGCA-21044(13)/1/2018 ANS Subject: Meteorological Service for Air Navigation 1. INTRODUCTION In pursuant to Article 28 of the Convention on International Civil Aviation each contracting State undertakes to provide Air navigation facilities and standard systems in accordance with standards which may be recommended or established from time to time, pursuant to this Convention. International Civil Aviation Organization adopts and amends from time to time, as may be necessary, international standards and recommended practices and procedures for Meteorological services for International Air Navigation in Annex 3. This CAR is issued under the provisions of Rule 29C and Rule 133A of the Aircraft Rules, 1937 for provision of Meteorological services for International Air Navigation to ensure the flow of information/data necessary for the safety, regularity and efficiency of international air navigation. 1.1 Applicability This CAR is applicable to the Meteorological service Provider engaged in the provisioning of Aviation Meteorological services for Air Navigation in India.1.2 Definitions Note 1. — The designation (RR) in these definitions indicates a definition which has been extracted from the Radio Regulations of the International Telecommunication Union (ITU) (see Handbook on Radio Frequency Spectrum Requirements for Civil Aviation including Statement of Approved ICAO Policies (Doc 9718)). Note 2. — These Standards and Recommended Practices are to be used in conjunction with the Procedures for Air Navigation Services — Meteorology (PANS-MET, Doc 10157). When the following terms are used in the Standards and Recommended Practices for Meteorological Service for International Air Navigation, they have the following meanings: Aerodrome - A defined area on land or water (including any buildings, installations and equipment) intended to be used either wholly or in part for the arrival, departure and surface movement of aircraft. Aerodrome Climatological summary- Concise summary of specified meteorological elements at an aerodrome, based on statistical data. Aerodrome climatological table - Table providing statistical data on the observed occurrence of one or more meteorological elements at an aerodrome. Aerodrome control tower - A unit established to provide air traffic control service to aerodrome traffic. Aerodrome elevation - The elevation of the highest point of the landing area. Aerodrome meteorological office - An office designated to provide meteorological service for aerodromes serving international air navigation. Aerodrome reference point - The designated geographical location of an aerodrome. Aeronautical fixed service (AFS) - A telecommunication service between specified fixed points provided primarily for the safety of air navigation and for the regular, efficient and economical operation of air services. Aeronautical fixed telecommunication network (AFTN) - A worldwide system of aeronautical fixed circuits provided, as part of the aeronautical fixed service, for the exchange of messages and/or digital data between aeronautical fixed stations having the same or compatible communications characteristics. Aeronautical meteorological station – A station designated to make observations and meteorological reports for use in international air navigation. Aeronautical mobile service (RR S1.32) - A mobile service between aeronautical stationsand aircraft stations, or between aircraft stations, in which survival craft stations may participate; emergency position-indicating radio beacon stations may also participate in this service on designated distress and emergency frequencies. Aeronautical telecommunication station - A station in the aeronautical telecommunication service. Aircraft - Any machine that can derive support in the atmosphere from the reactions of the air other than the reactions of the air against the earth’s surface. Aircraft observation - The evaluation of one or more meteorological elements made from an aircraft in flight. AIRMET information - Information issued by a meteorological watch office concerning the occurrence or expected occurrence of specified en-route weather phenomena which may affect the safety of low-level aircraft operations and which was not already included in the forecast issued for low-level flights in the flight information region concerned or sub- area thereof. Air-report- - A report from an aircraft in flight prepared in conformity with requirements for position, and operational and/ or meteorological reporting. Note. — Details of the AIREP form are given in the PANS-ATM (Doc 4444). Air traffic services unit - A generic term meaning variously, air traffic control unit, flight information Centre or air traffic services reporting office. Alternate aerodrome - An aerodrome to which an aircraft may proceed when it becomes either impossible or inadvisable to proceed to or to land at the aerodrome of intended landing where the necessary services and facilities are available, where aircraft performance requirements can be met and which is operational at the expected time of use. Alternate aerodromes include the following: Take-off alternate - An alternate aerodrome at which an aircraft would be able to land should this become necessary shortly after take-off and it is not possible to use the aerodrome of departure. En-route alternate - An alternate aerodrome at which an aircraft would be able to land in the event that a diversion becomes necessary while en route. Destination alternate - An alternate aerodrome at which an aircraft would be able to land should it become impossible or inadvisable to land at the aerodrome of intended landing. Note. — The aerodrome from which a flight departs may also be an en-route or a destination alternate aerodrome for that flight.Altitude - The vertical distance of a level, a point or an object considered as a point, measured from mean sea-level (MSL). Approach control unit - A unit established to provide air traffic control service to controlled flights arriving at, or departing from, one or more aerodromes. Appropriate ATS authority - The relevant authority designated by the State responsible for providing air traffic services in the airspace concerned. Area control centre (ACC) - A unit established to provide air traffic control service to controlled flights in control areas under its jurisdiction. Area navigation (RNAV) - A method of navigation which permits aircraft operations on any desired flight path within the coverage of ground- or space-based navigation aids or within the limits of the capability of self-contained aids, or a combination of these. Note. — Area navigation includes performance-based navigation as well as other operations that do not meet the definition of performance-based navigation. Automatic dependent surveillance — contract (ADS-C) - A means by which the terms of an ADS-C agreement will be exchanged between the ground system and the aircraft, via a data link, specifying under what conditions ADS-C reports would be initiated, and what data would be contained in the reports. Note. — The abbreviated term “ADS contract” is commonly used to refer to ADS event contract, ADS demand contract, ADS periodic contract or an emergency mode. Briefing - Oral commentary on existing and/or expected meteorological conditions. Cloud of operational significance - A cloud with the height of cloud base below 1500 m (5000 ft) or below the highest minimum sector altitude, whichever is greater or a cumulonimbus cloud or a towering cumulus cloud at any height. Consultation - Discussion with a meteorologist or another qualified person of existing and/or expected meteorological conditions relating to flight operations; a discussion includes answers to questions. Control area (CTA) - A controlled airspace extending upwards from as pacified limit above the earth. Cruising level - A level maintained during a significant portion of a flight. Elevation - The vertical distance of a point or a level, on or affixed to the surface of the earth, measured from mean sea level.Extended range operation - Any flight by an aero plane with two turbine power- units where the flight time at the one power-unit inoperative cruise speed (in ISA and still air conditions), from a point on the route to an adequate alternate aerodrome, is greater than the threshold time approved by the State of the Operator. Flight crew member - A licensed crew member charged with duties essential to the operation of an aircraft during a flight duty period. Flight documentation - Written or printed documents, including charts or forms, containing meteorological information for a flight. Flight information Centre (FIC) - A unit established to provide flight information service and alerting service. Flight information region (FIR) - An airspace of defined dimensions within which flight information service and alerting service are provided. Flight level. A surface of constant atmospheric pressure which is related to a specific pressure datum, 1 013.2 hecto Pascal’s (hPa), and is separated from other such surfaces by specific pressure intervals. Note 1. — A pressure type altimeter calibrated in accordance with the Standard Atmosphere: a) When set to a QNH altimeter setting, will indicate altitude; b) when set to a QFE altimeter setting, will indicate height above the QFE reference datum; and c) When set to a pressure of 1 013.2 hPa, may be used to indicate flight levels. Note 2. — The terms “height” and “altitude”, used in Note 1, indicate altimetry ratherthan geometric height sand altitudes. Forecast - A statement of expected meteorological conditions for a specified time or period, and for a specified area or portion of airspace. GAMET area forecast – An area forecast in abbreviated plain language for low-level flights for a flight information region or sub-area thereof, prepared by the meteorological office designated by the meteorological authority concerned and exchanged with meteorological offices in adjacent flight information regions, as agreed between the meteorological authorities concerned. Grid point data in digital form - Computer processed meteorological data for a set of regularly spaced points on a chart, for transmission from a meteorological computer to another computer in a code form suitable for automated use. Note. — In most cases such data are transmitted on medium or high speed telecommunications channels.Height - The vertical distance of a level, a point or an object considered as a point, measured from as pacified datum. Human Factors principles - Principles which apply to aeronautical design, certification, training, operations and maintenance and which seek safe interface between the human and other system components by proper consideration to human performance. International airways volcano watch (IAVW) - International arrangements for monitoring volcanic activity and providing notices, forecasts and warnings to aircraft of volcanic ash in the atmosphere. Note. — The IAVW is based on the cooperation of aviation and non-aviation operational units using information derived from observing sources and networks that are provided by States. The watch is coordinated by ICAO with the cooperation of other concerned international organizations. ICAO meteorological information exchange model (IWXXM). A data model for representing aeronautical meteorological information. Level - A generic term relating to vertical position of an aircraft in flight and meaning variously height, altitude or flight level. Meteorological authority - The authority entity providing or arranging for the provision of meteorological service for international air navigation on behalf of a Contracting State and providing regulation and oversight of the meteorological service. Meteorological bulletin-A text comprising meteorological information preceded by an appropriate heading. Meteorological information - Meteorological report, analysis, forecast, and any other statement relating to existing or expected meteorological conditions. Meteorological office. An office designated to provide meteorological service for international air navigation. Meteorological report - A statement of observed meteorological conditions related to a specified time and location. Meteorological satellite - An artificial Earth satellite making meteorological observations and transmitting these observations to Earth. Meteorological service provider. The relevant entity designated to provide meteorological service for international air navigation on behalf of a Contracting State.Meteorological watch office (MWO) - An office designated to provide information concerning the occurrence or expected occurrence of specified en-route weather and other phenomena in the atmosphere that may affect the safety of aircraft operations within its specified area of responsibility. Minimum sector altitude (MSA) - The lowest altitude which may be used which will provide a minimum clearance of 300 m (1 000 ft) above all objects located in the area contained within a sector of a circle of 46 km (25 NM) radius centered on a radio aid to navigation significant point, the aerodrome reference point (ARP) or the heliport reference point (HRP). Navigation specification - A set of aircraft and flight crew requirements needed to support performance-based navigation operations within a defined airspace. There are two kinds of navigation specifications: Required navigation performance (RNP) specification. A navigation specification based on area navigation that includes the requirement for performance monitoring and alerting, designated by the prefix RNP, e.g. RNP 4, RNP APCH. Area navigation (RNAV) specification. A navigation specification based on area navigation that does not include the requirement for performance monitoring and alerting, designated by the prefix RNAV, e.g. RNAV 5, RNAV 1. Note. — The Performance-based Navigation (PBN) Manual (Doc 9613), Volume II, contains detailed guidance on navigation specifications. Observation (meteorological) -The evaluation of one or more meteorological elements. Operational control - The exercise of authority over the initiation, continuation, diversion or termination of a flight in the interest of the safety of the aircraft and the regularity and efficiency of the flight. Operational flight plan - The operator’s plan for the safe conduct of the flight based on considerations of aero plane performance, other operating limitations and relevant expected conditions on the route to be followed and at the aerodromes concerned. Operational planning - The planning of flight operations by an operator. Operator - A person, organization or enterprise engaged in or offering to engage in an aircraft operation. Performance-based navigation (PBN) - Area navigation based on performance requirements for aircraft operating along an ATS route, on an instrument approach procedure orin a designated airspace.Note. — Performance requirements are expressed in navigation specification (RNAV specification, RNP specification) in terms of accuracy, integrity, continuity, availability and functionality needed for the proposed operation in the context of a particular air space concept. Pilot-in-command - The pilot designated by the operator, or in the case of general aviation, the owner, as being in command and charged with the safe conduct of a flight. Prevailing visibility - The greatest visibility value, observed in accordance with the definition of “visibility”, which is reached within at least half the horizon circle or within at least half of the surface of the aerodrome. These areas could comprise contiguous or non- contiguous sectors. Note. — This value may be assessed by human observation and/or instrumented systems. When instruments are installed, they are used to obtain the best estimate of the prevailing visibility. Prognostic chart - A forecast of a specified meteorological element(s) for a specified time or period and a specified surface or portion of airspace, depicted graphically on a chart. Quality assurance - All the planned and systematic activities implemented within the quality system, and demonstrated as needed, to provide adequate confidence that an entity will fulfil requirements for quality (ISO 9000*). Quality control - The operational techniques and activities that are used to fulfil requirements for quality (ISO 9000*). Quality management - All activities of the overall management function that determine the quality policy, objectives and responsibilities, and implementing them by means such as quality planning, quality control, quality assurance and quality improvement within the quality system (ISO 9000*). * ISO Standard 9000 — Quality Management Systems — Fundamentals and Vocabulary. Regional air navigation agreement - Agreement approved by the Council of ICAO normally on the advice of a regional air navigation meeting. Reporting point. A specified geographical location in relation to which the position of an aircraft can be reported. Rescue coordination Centre - A unit responsible for promoting efficient organization of search and rescue services and for coordinating the conduct of search and rescue operations within a search and rescue region. Runway - A defined rectangular area on a land aerodrome prepared for the landing and take- off of aircraft.Runway visual range (RVR) - The range over which the pilot of an aircraft on the Centre line of a runway can see the runway surface markings or the lights delineating the runway or identifying its Centre line. Search and rescue services unit - A generic term meaning, as the case may be, rescue coordination centre, rescue sub-centre or alerting post. SIGMET information - Information issued by a meteorological watch office concerning the occurrence or expected occurrence of specified en-route weather and other phenomena in the atmosphere that may affect the safety of aircraft operations. Space weather centre (SWXC). A global or regional centre designated by ICAO to monitor and provide advisory information on space weather phenomena expected to affect high-frequency radio communications, communications via satellite, GNSS-based navigation and surveillance systems and/or pose a radiation risk to aircraft occupants under the framework of space weather information service. Note. — A regional centre designated by ICAO supports global centres in the fulfilment of its responsibilities. Note. – A space weather centre is designated as global and/or regional. Space weather information service. A globally coordinated service where space weather centres provide information on space weather phenomena that may affect communications, navigation and surveillance systems and/or pose a radiation risk to aircraft occupants. Standard isobaric surface - An isobaric surface used on a worldwide basis for representing and analyzing the conditions in the atmosphere. State volcano observatory - A volcano observatory, designated by regional air navigation agreement, to monitor active or potentially active volcanoes within a State and to provide information on volcanic activity to its associated area control Centre/flight information Centre, meteorological watch office and volcanic ash advisory Centre and/or volcanic ash in the atmosphere. Threshold - The beginning of that portion of the runway usable for landing. Touchdown zone - The portion of a runway, beyond the threshold, where it is intended landing aero planes first contact the runway. Tropical cyclone - Generic term fora non-frontal synoptic scale cyclone originating over tropical or sub-tropical waters with organized convection and definite cyclonic surface wind circulation.Tropical cyclone advisory Centre (TCAC) – A meteorological Centre designated by regional air navigation agreement to provide advisory information to meteorological watch offices, world area forecast centers and international OPMET data banks regarding the position, forecast direction and speed of movement, central pressure and maximum surface wind of tropical cyclones. Upper-air chart - A meteorological chart relating to a specified upper-air surface or layer of the atmosphere. Visibility - Visibility for aeronautical purposes is the greater of: a) the greatest distance at which a black object of suitable dimensions, situated near the ground, can be seen and recognized when observed against a bright background; b) The greatest distance at which lights in the vicinity of 1 000 candelas can be seen and identified against an unlit background. Note. — the two distances have different values in air of a given extinction coefficient, and the latter b) varies with the background illumination. The former a) is represented by the meteorological optical range (MOR). Volcanic ash advisory Centre (VAAC) - A meteorological Centre designated by regional air navigation agreement to provide advisory information to meteorological watch offices, area control centers, flight information centers, world area forecast centers and international OPMET data banks regarding the lateral and vertical extent and forecast movement of volcanic ash in the atmosphere. VOLMET - Meteorological information for aircraft in flight. Data link-VOLMET (D-VOLMET) - Provision of current aerodrome routine meteorological reports (METAR) and aerodrome special meteorological reports (SPECI), aerodrome forecasts (TAF), SIGMET, special air-reports not covered by a SIGMET and, where available, AIRMET via datalink. VOLMET broadcast - Provision, as appropriate, of current METAR, SPECI, TAF and SIGMET by means of continuous and repetitive voice broadcasts. World area forecast Centre (WAFC) - A meteorological Centre designated to prepare and issue significant weather forecasts and upper-air forecasts in digital form on a global basis direct to States using the aeronautical fixed service Internet- based services. World area forecast system (WAFS) - A worldwide system by which world area forecast centres provide aeronautical meteorological en-route forecasts in uniform standardized formats.1.3 Terms used with a limited meaning For the purpose of this CAR, the following terms are used with a limited meaning as indicated below: a) to avoid confusion in respect of the term “service” between the meteorological service considered as an administrative entity and the service which is provided, “meteorological authority” is used for the former and “service” for the latter; b)a) “provide” is used solely in connection with the provision of service; c)b) “issue” is used solely in connection with cases where the obligation specifically extends to sending out the information to a user; d)c) “make available” is used solely in connection with cases where the obligation ends with making the information accessible to a user; and e)d) “Supply” is used solely in connection with cases where either c) or d) applies.2. General Provisions 2.1 Objective, determination and provision of meteorological service 2.1.1 The objective of meteorological service shall be to contribute towards the safety, regularity and efficiency of international air navigation. 2.1.2 The objective shall be achieved by supplying the following users: operators, flight crew members, air traffic services units, search and rescue services units, airport managements and others concerned with the conduct or development of international air navigation, with the meteorological information necessary for the performance of their respective functions. 2.1.3 The meteorological services to be provided for international air navigation over Indian Territory shall be in accordance with the provisions contained in this CAR. Meteorological service to be provided for international air navigation over international waters and other areas outside the territory of India shall be in accordance with regional air navigation agreements. 2.1.4 India Meteorological Department (IMD) shall provide Meteorological Services for safety, regularity, and efficiency of international air navigation in accordance with the provisions of this CAR and regional air navigation agreements in this regard. 2.1.42.1.5 Each Contracting State shall designate an entity (or several entities), hereinafter referred to as the meteorological service provider, to provide meteorological service for international air navigation on behalf of the Contracting State. Details of the meteorological service provider(s) so designated shall be included in the State aeronautical information publication, in accordance with Annex 15, Chapter 5. Note1. — Detailed specifications concerning presentation and contents of the aeronautical information publication is provided in PANS-AIM (Doc 10066), Appendix 2. Note2. — IMD shall be the designated Meteorological Authority for provision of Meteorological Services for air navigation over the Indian Territory; including international waters and other areas outside the territory of India in accordance with regional air navigation agreement. 2.1.52.1.6 IMD shall ensure compliance with the requirements of the World Meteorological Organization (WMO) in respect of qualifications, competencies, education and training of meteorological personnel providing service for international air navigation. Note.— Requirements concerning qualifications, competencies, education and training of meteorological personnel in aeronautical meteorology are given in WMO PublicationNo. 49, Technical Regulations, Volume I — General Meteorological Standards and Recommended Practices, Part V — Qualifications and Competencies of Personnel Involved in the Provision of Meteorological (Weather and Climate) and Hydrological Services, Part VI — Education and Training of Meteorological Personnel, and Appendix A — Basic Instruction Packages. 2.2 Supply, use, quality management and interpretation of meteorological information 2.2.1 Close liaison shall be maintained between those concerned with the supply and those concerned with the use of meteorological information on matters which affect the provision of meteorological service for international air navigation. 2.2.2 IMD shall ensure establishment and implementation of a properly organized quality system comprising procedures, processes and resources necessary to provide for the quality management of the meteorological information to be supplied to the users listed in 2.1.2. 2.2.3 The quality system established in accordance with 2.2.2 should be in conformity with the International Organization for Standardization (ISO) 9000 series of quality assurance standards and should be certified by an approved organization. Note. — The ISO 9000 series of quality assurance standards provide a basic framework for the development of a quality assurance programme. The details of a successful programme are to be formulated by each State and in most cases are unique to the State organization Guidance on the establishment and implementation of quality management system is given in the Guide to the Implementation of Quality Management Systems for National Meteorological and Hydrological Services and Other Relevant Service Providers (WMO-No. 1100). 2.2.4 The quality system should provide the users with assurance that the meteorological information supplied complies with the stated requirements in terms of the geographical and spatial coverage, format and content, time and frequency of issuance and period of validity, as well as the accuracy of measurements, observations and forecasts. When the quality system indicates that meteorological information to be supplied to the users does not comply with the stated requirements, and automatic error correction procedures are not appropriate, such information should not be supplied to the users unless it is validated with the originator. Note. — Requirements concerning the geographical and spatial coverage, format and content, time and frequency of issuance and period of validity of meteorological information to be supplied to aeronautical users are given contained in para 3, 4, 6, 7, 8, 9 and 10 and Appendices 2, 3, 5, 6, 7, 8 and 9 of this CAR and the relevant regional air navigation plans. Guidance concerning the accuracy of measurement and observation, and accuracy of forecasts is given in Attachments A and B respectively, to this CAR.2.2.5 In regard to the exchange of meteorological information for operational purposes, the quality system should include verification and validation procedures and resources for monitoring adherence to the prescribed transmission schedules for individual messages and/or bulletins required to be exchanged, and the times of their filing for transmission. The quality system should be capable of detecting excessive transit times of messages and bulletins received. Note. — Requirements concerning the exchange of operational meteorological information are given in para 11 and Appendix 10 of this CAR. 2.2.6 Demonstration of compliance of the quality system applied shall be by audit. If non- conformity of the system is identified, action shall be initiated to determine and correct the cause. All audit observations shall be evidence- based and properly documented. 2.2.7 Owing to the variability of meteorological elements in space and time, to limitations of observing techniques and to limitations caused by the definitions of some of the elements, the specific value of any of the elements given in a report shall be understood by the recipient to be the best approximation of the actual conditions at the time of observation. Note. — Guidance on the operationally desirable accuracy of measurement or observation is given contained in Attachment A of this CAR. 2.2.8 Owing to the variability of meteorological elements in space and time, to limitations of forecasting techniques and to limitations caused by the definitions of some of the elements, the specific value of any of the elements given in a forecast shall be understood by the recipient to be the most probable value which the element is likely to assume during the period of the forecast. Similarly, when the time of occurrence or change of an element is given in a forecast, this time shall be understood to be the most probable time. Note. — Guidance on the operationally desirable accuracy of forecasts is given contained in Attachment B of this CAR. 2.2.9 The meteorological information supplied to the users listed in 2.1.2 shall be consistent with Human Factors principles and shall be in forms which require a minimum of interpretation by these users, as specified in the following Paras. Note. — Guidance material on the application of Human Factors principles can be found in the Human Factors Training Manual (Doc 9683). 2.2.10 IMD should ensure that the meteorological information supplied to the users listed in 2.1.2 is provided through information services. Note 1. — In the context of system-wide information management (SWIM), the notion of information service addresses machine interaction in a service-oriented architecture.Note 2. — Procedures on information services are contained in the Procedures for Air Navigation Services – Information (PANS-IM, DOC 10199). Note 3. — Guidance material on information services can be found in the Manual on System-wide Information Implementation (Doc 10203). 2.3 Notifications required from operators 2.3.1 An operator requiring meteorological service or changes in existing meteorological service shall notify IMD or concerned aerodrome meteorological office, sufficiently in advance. The minimum amount of advance notice required shall be as agreed between the IMD and the Operator concerned. 2.3.2 IMD shall be notified by the operator requiring service when: a) new routes or new types of operations are planned; b) changes of a lasting character are to be made in scheduled operations; and c) other changes, affecting the provision of meteorological service, are planned. Such information shall contain all details necessary for the planning of appropriate arrangements by IMD. 2.3.3 The operator or a flight crew member shall ensure that, where required by the meteorological authority in consultation with users, the aerodrome meteorological office concerned is notified: a) of flight schedules; b) when non-scheduled flights are to be operated; and c) When flights are delayed, advanced or cancelled. 2.3.4 The notification to the aerodrome meteorological office, of individual flights should contain the following information except that, in the case of scheduled flights, the requirement for some or all of this information may be waived as agreed between the aerodrome meteorological office and the operator concerned: a) aerodrome of departure and estimated time of departure; b) destination and estimated time of arrival; c) route to be flown and estimated times of arrival at, and departure from, any intermediate aerodrome (s); d) alternate aerodromes needed to complete the operational flight plan and taken from the relevant list contained in the regional air navigation plan; e) cruising level; f) type of flight, whether under visual or instrument flight rules; g) type of meteorological information requested for a flight crew member, whether flight documentation and/or briefing or consultation; and h) Time at which briefing, consultation and/or flight documentation are required.3. GLOBAL SYSTEMS, SUPPORTING CENTRE AND METEOROLOGICAL OFFICES Note. – Please refer Appendix 2 of this CAR for technical specifications and other detailed criteria. 3.1 Objective of the world area forecast system (WAFS) The technical specifications related to World Area Forecast System (WAFS) are Stipulates in Chapter 3 and Appendix 2 of ICAO Annex 3 for the contracting states which have accepted responsibilities for providing a World Area Forecast Centers (WAFC). India is not a WAFC. However, the Service Provider shall have to be familiar with the technical specifications so as to be able to interact with them and use its products/services effectively. 3.23.1 World area forecast centers (WAFC) within the framework of the world area forecast system The technical specifications related to World Area Forecast System (WAFS) are stipulates in Chapter 3 and Appendix 2 of ICAO Annex 3 for the contracting states which have accepted responsibilities for providing a World Area Forecast Centers (WAFC). India is not a WAFC. However, the Service Provider shall have to be familiar with the technical specifications so as to be able to interact with them and use its products/services effectively. Note.— The objective of the world area forecast system (WAFS) is to supply meteorological authorities and other users with global aeronautical meteorological en- route forecasts in digital form. This objective is achieved through a comprehensive, integrated, worldwide and, as far as practicable, uniform system, and in a cost-effective manner, taking full advantage of evolving technologies. 3.2.13.1.1 Intentionally left blank. 3.2.23.2 Intentionally left blank. 3.3 Aerodrome meteorological offices 3.3.1 IMD shall establish one or more aerodrome and/or other meteorological offices which shall be adequate for the provision of the meteorological service required to satisfy the needs of international air navigation. 3.3.2 An aerodrome meteorological office shall carry out all or some of the following functions as necessary to meet the needs of flight operations at the aerodrome: a) prepare and/or obtain forecasts and other relevant information for flights with which itis concerned; the extent of its responsibilities to prepare forecasts shall be related to the local availability and use of en- route and aerodrome forecast material received from other offices; b) Prepare and/or obtain forecasts of local meteorological conditions; c) Maintain a continuous survey of meteorological conditions over the aerodromes for which it is designated to prepare forecasts; d) Provide briefing, consultation and flight documentation to flight crew members and/or other flight operations personnel; e) Supply other meteorological information to aeronautical users; f) Display the available meteorological information; g) Exchange meteorological information with other aerodrome meteorological offices; and h) Supply information received on pre-eruption volcanic activity, a volcanic eruption or volcanic ash cloud, to its associated air traffic services unit, Aeronautical information service unit and meteorological watch office as agreed between the meteorological service provider, aeronautical information service and appropriate ATS authorities authority concerned. 3.3.3 The aerodromes for which landing forecasts are required shall be determined by regional air navigation agreement. 3.3.4 For an aerodrome without an aerodrome meteorological office located at the aerodrome: a) The meteorological authority concerned Contracting State shall designate one or more aerodrome meteorological office(s) to supply meteorological information as required; and b) The competent authorities shall establish means by which such information can be supplied to the aerodromes concerned. 3.4 Meteorological watch offices (MWO) 3.4.1 IMD shall establish one or more meteorological watch offices (MWO) for provision of services enumerated under para 3.4.2 to cover all the Flight Information Regions of India. Note. — Guidance on the bilateral or multilateral arrangements between Contracting States for the provision of meteorological watch office services, including for cooperation and delegation, can be found provision in the Manual of Aeronautical Meteorological Practice (Doc 8896). 3.4.2 A MWO shall: a) maintain watch over meteorological conditions affecting flight operations within its area of responsibility; b) prepare SIGMET and other information relating to its area of responsibility; c) supply SIGMET information and, as required, other meteorological information to associated air traffic services units; d) disseminate SIGMET information;e) when required by regional air navigation agreement, in accordance with 7.2.1 7 5.1.1 1) prepare AIRMET information related to its area of responsibility; 2) supply AIRMET information to associated air traffic services units; and 3) disseminate AIRMET information; f) supply information received on pre-eruption volcanic activity, a volcanic eruption and volcanic ash cloud for which a SIGMET has not already been issued, to its associated ACC/FIC, as agreed between the meteorological service provider and appropriate ATS authorities authority concerned, and to its associated VAAC as determined by regional air navigation agreement; and g) Supply information received concerning the release of radioactive materials into the atmosphere, in the area for which it maintains watch or adjacent areas, to its associated ACC/FIC, as agreed between the meteorological service provider and ATS authorities authority concerned, and to aeronautical information service units, as agreed between the meteorological service provider and appropriate civil aviation authorities authority concerned. The information shall comprise location, date and time of the release, and forecast trajectories of the radioactive materials. Note. — The information is provided by WMO regional specialized meteorological centers (RSMC) for the provision of transport model products for radiological environmental emergency response, at the request of the delegated authority of the State in which the radioactive material was released into the atmosphere, or the International Atomic Energy Agency (IAEA). The information is sent by the RSMC to a single contact point of the national meteorological service in each State. This contact point has the responsibility of redistributing the RSMC products within the State concerned. Furthermore, the information is provided by IAEA to RSMC co-located with VAAC London (designated as the focal point) which in turn notifies the ACCs/FICs concerned about the release. 3.4.3 The boundaries of the area over which meteorological watch is to be maintained by a MWO shall, be coincident with the boundaries of a FIR or a CTA or a combination of FIRs and/or CTAs. 3.4.33.4.4 An MWO should coordinate the content of SIGMET and the provision of harmonized SIGMET information with neighbouring MWO(s), especially when the en-route weather phenomenon extends or is expected to extend beyond the MWO’s specified area of responsibility. 3.5 Volcanic ash advisory centers (VAAC) The technical specifications related to Volcanic Ash Advisory Centers (VAACs) are stipulated in Chapter 3 and Appendix 2 of ICAO Annex 3 for the contracting states which have accepted responsibilities for providing a VAAC.India is not a VAAC. However, the Service Provider shall have to be familiar with the technical specifications so as to be able to interact with VAAC and use its products/services effectively. 3.6 State volcano observatories Intentionally left blank. 3.7 Tropical cyclone advisory centers 3.7.1 IMD shall establish Tropical Cyclone Advisory Centers (TCAC) having adequate facilities to: a) monitor the development of tropical cyclones in its area of responsibility, using geostationary and polar-orbiting satellite data, radar data and other meteorological information; b) issue advisory information concerning the position of the cyclone Centre, change in its intensity at the time of observation its direction and speed of movement, central pressure and maximum surface wind near the Centre; in abbreviated plain language to: 1) MWOs in its area of responsibility; 2) other TCACs whose areas of responsibility may be affected; and 3) WAFCs, international OPMET data banks, and centers designated by regional air navigation agreement for the operation of aeronautical fixed service Internet-based services; and c) Issue updated advisory information to MWOs for each tropical cyclone, as necessary, but at least every six hours. 3.8 Space weather centers (SWXC) The technical specifications related to SWXC are stipulated in Chapter 3, Appendix 2 and Attachment E of ICAO Annex 3 for the contracting states which have accepted responsibilities to monitor and provide advisory information on space weather. India is not a SWXC. However, the Service Provider shall have to be familiar with the technical specifications so as to be able to interact with SWXC and use its products/services effectively. 3.8.1 Intentionally left blank. 3.8.2 Intentionally left blank. 3.8.3 Intentionally left blank.4. AERODROME METEOROLOGICAL OBSERVATIONS AND REPORTS OBSERVATIONAL INFORMATION Note. — Please refer Appendix 3 of this CAR for technical specifications and detailed criteria. The Standards and Recommended Practices in this chapter are to be used in conjunction with the Procedures for Air Navigation Services — Meteorology (PANS-MET, Doc 10157), Chapter 2 4.1 Aeronautical meteorological stations and observations 4.1.1 IMD shall establish at aerodromes and other points of significance to international air navigation, such aeronautical meteorological stations as it determines to be necessary. An aeronautical meteorological station may be a separate station or may be combined with a synoptic station. Note. — Aeronautical meteorological stations may include sensors installed outside the aerodrome, where considered justified, by the meteorological authority to ensure the compliance of meteorological service for international air navigation with the provisions of this CAR. 4.1.2 IMD should establish, or arrange for the establishment of, aeronautical meteorological stations on offshore structures or at other points of significance if requested by the operators of the concerned offshore structure in support of helicopter operations to offshore structures. 4.1.3 Aeronautical meteorological stations shall make routine observations at fixed intervals. At aerodromes, the routine observations shall be supplemented by special observations whenever specified changes occur in respect of surface wind, visibility, runway visual range, present weather, clouds and/or air temperature. 4.1.4 IMD shall establish a mechanism for its the aeronautical meteorological stations to be inspected at sufficiently frequent intervals to ensure that a high standard of observations is maintained, that instruments and all their indicators are functioning correctly, and to check whether the exposure of the instruments has changed significantly. Note. — Guidance on the inspection of aeronautical meteorological stations including the frequency of inspections is given in the Manual on Automatic Meteorological Observing Systems at Aerodromes (Doc 9837). 4.1.5 At aerodromes, with runways intended for Category II and III instrument approach and landing operations, automated equipment for measuring or assessing, as appropriate, and for monitoring and remote indicating of surface wind, visibility, runway visual range,height of cloud base, air and dew-point temperatures and atmospheric pressure shall be installed to support approach and landing and take-off operations. These devices shall be integrated automatic systems for acquisition, processing, dissemination and display in real time of the meteorological parameters affecting landing and take-off operations. The design of integrated automatic systems shall observe Human Factors principles and include back-up procedures. Note 1. — Categories of precision approach and landing operations are defined in CAR Section 8 series B part 1. Note 2. — Guidance material on the application of Human Factors principles can be found in the ICAO Human Factors Training Manual (ICAO Doc 9683). 4.1.6 At aerodromes, with runways intended for Category I instrument approach and landing operations, automated equipment for measuring or assessing, as appropriate, and for monitoring and remote indicating of surface wind, visibility, runway visual range, height of cloud base, air and dew-point temperatures and atmospheric pressure should be installed to support approach and landing and take-off operations. These devices should be integrated automatic systems for acquisition, processing, dissemination and display in real time of the meteorological parameters affecting landing and take-off operations. The design of integrated automatic systems should observe Human Factors principles and include back-up procedures. 4.1.7 Where an integrated semi-automatic system is used for the dissemination/display of meteorological information, it should be capable of accepting the manual insertion of data covering those meteorological elements which cannot be observed by automatic means. 4.1.8 The observations shall form the basis for the preparation of reports to be disseminated at the aerodrome of origin and of reports to be disseminated beyond the aerodrome of origin. 4.1.9 The meteorological instruments used at an aerodrome should be situated in such a way as to supply data which are representative of the area for which the measurements are required. Note. — Specifications concerning the siting of equipment and installations on operational areas, aimed at reducing the risk of damage to aircraft to a minimum, are contained in Annex 14, Volume I, Chapter 9. 4.1.10 Meteorological instruments at aeronautical meteorological stations should be exposed, operated and maintained in accordance with the practices, procedures and specifications promulgated by the World Meteorological Organization (WMO).Note. — Practices, procedures and specifications of WMO are contained in the Guide to Instruments and Methods of Observation (WMO-No. 8), Volume I— Measurement of Meteorological Variables, Volume II— Observing Systems; and Volume III— Quality Assurance and Management of Observing Systems. 4.1.11 The observers at an aerodrome should be located, in so far as is practicable, so as to supply data which are representative of the area for which the observations are required. 4.1.84.1.12 Where automated equipment forms part of an integrated semiautomatic observing system, displays of data which are made available to the local air traffic services units should be a subset of and displayed in parallel to those available in the local meteorological service unit. In those displays, each meteorological element should be annotated to identify, as appropriate, the locations for which the element is representative. 4.2 Agreement between meteorological authorities service provider and appropriate air traffic services authorities authority An agreement between the IMD and the ATS authority service provider should be established to cover, amongst other things: a) the provision in air traffic services units of displays related to integrated automatic systems; b) the calibration and maintenance of these displays/ instruments; c) the use to be made of these displays/instruments by air traffic services personnel; d) as and where necessary, supplementary visual observations (for example, of meteorological phenomena of operational significance in the climb-out and approach areas) if and when made by air traffic services personnel to update or supplement the information supplied by the meteorological station; e) meteorological information obtained from aircraft taking off or landing (for example, on wind shear); and f) if available, meteorological information obtained from ground weather radar. Note. —Guidance on the subject of coordination between ATS and aeronautical meteorological services is contained in the ICAO Manual on Coordination between Air Traffic Services, Aeronautical Information Services and Aeronautical Meteorological Services (ICAO Doc 9377). 4.3 Routine observations and reports Note.— Procedures and technical specifications related to this section are contained in the PANS-MET (Doc 10157), Section 2.1.1. 4.3.1 At aerodromes, routine observations shall be made throughout the 24 hours each day, unless otherwise agreed between IMD, the appropriate ATS authority, and the operator concerned. Such observations shall be made at intervals of one hour or, if so determinedby regional air navigation agreement, at intervals of one half hour. At other aeronautical meteorological stations, such observations shall be made as determined by the IMD taking into account the requirements of air traffic services units and aircraft operations. 4.3.2 Reports of routine observations shall be issued as: a) local routine reports, only for dissemination at the aerodrome of origin, (intended for arriving and departing aircraft); and Note. — Technical specifications of the issuance of local routine reports are contained in the PANS-MET (Doc 10157), Chapter 2, 2.1.1.1. b) METAR for dissemination beyond the aerodrome of origin (mainly intended for flight planning, VOLMET broadcasts and D-VOLMET). Note 1.— Technical specifications of the issuance and the dissemination of METAR are contained in the PANS-MET (Doc 10157), Chapter 2, 2.1.1.2 and 2.1.1.3. Note 2. — Meteorological information used in ATIS (voice- ATIS and D-ATIS) is to be extracted from the local routine report, in accordance with CAR Section 9 Series E Part I Para 4.3.6.1g. 4.3.3 At aerodromes that are not operational throughout 24 hours in accordance with 4.3.1, METAR shall be issued prior to the aerodrome resuming operations in accordance with agreement between IMD, ATS authority and operator. 4.4 Special observations and reports Note. — Procedures and technical specifications related to this section are contained in the PANS-MET (Doc 10157), Sections 2.1.1 and 2.1.2. 4.4.1 A list of criteria for special observations shall be established by the meteorological authority service provide in consultation with the appropriate ATS authority, operators and others concerned. 4.4.2 Reports of special observations shall be issued as: a) local special reports, only for dissemination at the aerodrome of origin, (intended for arriving and departing aircraft); and Note.— Technical specifications of the issuance of local special reports are contained in the PANSMET (Doc 10157) Chapter 2, 2.1.1.1. b) SPECI for dissemination beyond the aerodrome of origin (mainly intended for flight planning, VOLMET broadcasts and D-VOLMET) unless METAR are issued at half- hourly intervals.Note 1.— Technical specifications of the issuance and the dissemination of SPECI are contained in the PANS-MET (Doc 10157) Chapter 2, 2.1.1.2 and 2.1.1.3. Note 2. — Meteorological information used in ATIS (voice- ATIS and D-ATIS) is to be extracted from the local special report, in accordance with CAR Section 9 Series E Part I Para 4.3.6.1. 4.4.3 At aerodromes that are not operational throughout 24 hours in accordance with 4.3.1, following the resumption of the issuance of METAR, SPECI shall be issued, as necessary. 4.5 Contents of Characteristic of meteorological Reports Note. — Procedures and technical specifications related to this section are contained in the PANS-MET (Doc 10157), Section 2.1.1. 4.5.1 Local routine reports, local special reports, METAR and SPECI shall contain the following meteorological elements in the order indicated: a) identification of the type of report; b) location indicator; c) time of the observation; d) identification of an automated or missing report, when applicable; ea) surface wind direction and speed; fb) visibility; gc) runway visual range, when applicable; hd) present weather; ie) cloud amount, cloud type (only for cumulonimbus and towering cumulus clouds) and height of cloud base or, where measured, vertical visibility; jf) air temperature and dew-point temperature; and kg) QNH and, when applicable, QFE (QFE included only in local routine report and special reports). Note. — The location indicators referred to under b) and their significations are published in Location Indicators (Doc 7910). 4.5.2 In addition to elements listed under 4.5.1 a) to k), local routine reports, local special reports, METAR and SPECI should contain supplementary information to be placed after element k). 4.5.3 Optional elements included under supplementary information shall be included in METAR and SPECI in accordance with regional air navigation agreement.4.6 Observing and reporting meteorological elements Note.— Procedures and technical specifications related to this section are contained in the PANS-MET (Doc 10157), Section 2.2. 4.6.1 Surface Wind 4.6.1.1 The mean direction and the mean speed of the surface wind shall be measured, as well as significant variations of the wind direction and speed, and reported in degrees true and meter per second (or knots), respectively. 4.6.1.2 When local routine and special reports are used for departing aircraft, the surface wind observations for these reports should be representative of conditions along the runway; when local routine and special reports are used for arriving aircraft, the surface wind observations for these reports should be representative of the touchdown zone. 4.6.1.3 For METAR and SPECI, the surface wind observations should be representative of conditions above the whole runway where there is only one runway and the whole runway complex where there is more than one runway. Note. — The date and the annual change may be shown. 4.6.2 Visibility 4.6.2.1 The visibility as defined in this CAR shall be measured or observed, and reported in meters or kilometers. Note. — Guidance on the conversion of instrument readings into visibility is given in Attachment D of this CAR. 4.6.2.2 Intentionally left blank 4.6.2.3 For METAR and SPECI, the visibility observations should be representative of the aerodrome. 4.6.3 Runway visual range 4.6.3.1 Runway visual range as defined in this CAR shall be assessed on all runways intended for Category II and III instrument approach and landing operations. 4.6.3.2 Runway visual range as defined in this CAR should be assessed on all runways intended for use during periods of reduced visibility, including: a) precision approach runways intended for Category I instrument approach and landing operations; and b) Runways used for take-off and having high-intensity edge lights and/or Centre line lights.Note. — Precision approach runways are defined in CAR Section 4 Series ‘B', Part 1, under “Instrument runway”. 4.6.3.3 The runway visual range, assessed in accordance with 4.6.3.1 and 4.6.3.2, shall be reported in meters throughout periods when either the visibility or the runway visual range is less than 1500 m. 4.6.3.4 Runway visual range assessments shall be representative of: a) the touchdown zone of the runway intended for non-precision or Category I instrument approach and landing operations; b) the touchdown zone and the mid-point of the runway intended for Category II instrument approach and landing operations; and c) The touchdown zone, the mid-point and stop-end of the runway intended for Category III instrument approach and landing operations. 4.6.3.5 The units providing air traffic service and aeronautical information service for an aerodrome shall be kept informed without delay of changes in the serviceability status of the automated equipment used for assessing runway visual range. 4.6.4 Present Weather 4.6.4.1 The present weather occurring at the aerodrome shall be observed and reported as necessary. The following present weather phenomena shall be identified, as a minimum: a) precipitation rain, drizzle, snow and freezing precipitation (including intensity thereof), b) obscurations haze, mist, fog, freezing fog and thunderstorms (including thunderstorms in the vicinity). 4.6.4.2 For local routine and special reports, the present weather information shall be representative of conditions at the aerodrome. 4.6.4.3 For METAR and SPECI, the present weather information shall be representative of conditions at the aerodrome and, for certain specified present weather phenomena, in its vicinity. 4.6.5 Clouds 4.6.5.1 Cloud amount, cloud type and height of cloud base shall be observed, and reported as necessary to describe the clouds of operational significance. When the sky is obscured, vertical visibility shall be observed and reported, where measured, in lieu of cloud amount, cloud type and height of cloud base. The height of cloud base and vertical visibility shall be reported in meters (or feet). 4.6.5.2 Intentionally left blank.4.6.5.3 Cloud observations for METAR and SPECI shall be representative of the aerodrome and its vicinity. 4.6.6 Air temperature and dew-point temperature 4.6.6.1 The air temperature and the dew-point temperature shall be measured and reported in degrees Celsius. 4.6.6.2 Observations of air temperature and dew-point temperature for local routine reports, local special reports, METAR and SPECI should be representative of the whole runway complex. 4.6.7 Atmospheric pressure The atmospheric pressure shall be measured, and QNH and QFE values shall be computed and reported in hector Pascals. 4.6.8 Supplementary information Observations made at aerodromes shall include the available supplementary information concerning significant meteorological conditions, particularly those in the approach and climb-out areas. Where practicable, the information should identify the location of the meteorological condition. 4.7 Reporting meteorological information from automatic observing systems Intentionally Left Blank. 4.7.1 Intentionally Left Blank. 4.7.2 Intentionally Left Blank. 4.7.3 Intentionally Left Blank. 4.8 Observationsing and reportsing of volcanic activity Note. — Procedures and technical specifications related to this section are contained in the PANS-MET (Doc 10157), Section 2.3. The occurrence of pre-eruption volcanic activity, volcanic eruptions and volcanic ash cloud should be reported without delay to the associated air traffic services unit, aeronautical information services unit and meteorological watch office. The report should be made in the form of a volcanic activity report comprising the following information in the order indicated: a) message type, VOLCANIC ACTIVITY REPORT;b) station identifier, location indicator or name of station; c) date/time of message; d) location of volcano and name if known; and e) concise description of event including, as appropriate, level of intensity of volcanic activity, occurrence of an eruption and its date and time, and the existence of a volcanic ash cloud in the area together with direction of ash cloud movement and height. Note. — Pre-eruption volcanic activity in this context means unusual and/or increasing volcanic activity which could presage a volcanic eruption. 4.9 Dissemination of meteorological reports 4.9.1 METAR and SPECI 4.9.1.1 METAR and SPECI shall be disseminated to international OPMET databanks and the centres designated by regional air navigation agreement for the operation of aeronautical fixed service Internet based services, in accordance with regional air navigation agreement. 4.9.1.2 METAR and SPECI shall be disseminated to other aerodromes in accordance with regional air navigation agreement. 4.9.1.3 SPECI representing a deterioration in conditions shall be disseminated immediately after the observation. A SPECI representing a deterioration of one weather element and an improvement in another element shall be disseminated immediately after the observation. 4.9.1.4 A SPECI representing an improvement in conditions should be disseminated only after the improvement has been maintained for 10 minutes; it should be amended before dissemination, if necessary, to indicate the conditions prevailing at the end of that 10-minute period. 4.9.2 Local routine report and local special report 4.9.2.1 Local routine reports shall be transmitted to local air traffic services units and shall be made available to the operators and to other users at the aerodrome. 4.9.2.2 Local special reports shall be transmitted to local air traffic services units as soon as the specified conditions occur. However, as agreed between the meteorological service provider and the appropriate ATS authority, they need not be issued in respect of: a) any element for which there is in the local air traffic services unit a display corresponding to the one in the meteorological station, and where arrangements are in force for the use of this display to update information included in local routine report and local special report; and b) runway visual range, when all changes of one or more steps on the reporting scale in use are being reported to the local air traffic services unit by an observer on the aerodrome. Local special reports shall also be made available to the operators and to other users at the aerodrome5. AIRCRAFT OBSERVATIONS AND REPORTS METEOROLOGICAL OBSERVATIONAL INFORMATION Note. — Technical specifications and detailed criteria related to this Para are given in Appendix 4 of this CAR. The Standards and Recommended Practices in this chapter are to be used in conjunction with the Procedures for Air Navigation Services — Meteorology (PANS-MET, Doc 10157), Chapter 3. 5.1 Obligations of States Each Contracting State shall arrange, according to the provisions of this Para, for observations to be made by aircraft of its registry operating on international air routes and for the recording and reporting of these observations. 5.2 Types of aircraft observations The following aircraft observations shall be made: a) routine aircraft observations during en-route and climb-out phases of the flight; and b) Special and other non-routine aircraft observations during any phase of the flight. 5.3 Routine aircraft observations - designation 5.3.1 When air-ground data link is used and automatic dependent surveillance - contract (ADS- C) or secondary surveillance radar (SSR) Mode S is being applied, automated routine observations should be made every 15 minutes during the en-route phase and every 30 seconds during the climb-out phase for the first 10 minutes of the flight. 5.3.2 For helicopter operations to and from aerodromes on offshore structures, routine observations should be made from helicopters at points and times as agreed between the meteorological authorities service provider and the helicopter operators concerned. 5.3.3 In the case of air routes with high-density air traffic (e.g. organized tracks), an aircraft from among the aircraft operating at each flight level shall be designated, at approximately hourly intervals, to make routine observations in accordance with 5.3.1. The designation procedures shall be in accordance with regional air navigation agreement. 5.3.4 In the case of the requirement to report during the climb-out phase, an aircraft shall be designated, at approximately hourly intervals, at each aerodrome to make routine observations in accordance with 5.3.1. 5.4 Routine aircraft observations – exemptions Aircraft not equipped with air-ground data link shall be exempted from making routineaircraft observations. 5.5 Special aircraft observations Special observations shall be made by all aircraft whenever the following conditions are encountered or observed: a) moderate or severe turbulence; or b) moderate or severe icing; or c) severe mountain wave; or d) thunderstorms, without hail, that are obscured, embedded, widespread or in squall lines; or e) thunderstorms, with hail, that are obscured, embedded, widespread or in squall lines; or f) heavy dust storm or heavy sandstorm; or g) volcanic ash cloud; or h) Pre-eruption volcanic activity or a volcanic eruption. i) As of 5 4 November 2021, runway braking action encountered is not as good as reported. Note. — Pre-eruption volcanic activity in this context means unusual and/or increasing volcanic activity which could presage a volcanic eruption. 5.6 Other non-routine aircraft observations Note. — Procedures and technical specifications related to this section are contained in the PANS-MET (Doc 10157), Section 3.2. When other meteorological conditions not listed under 5.5, e.g. wind shear, are encountered and which, in the opinion of the pilot-in-command, may affect the safety or markedly affect the efficiency of other aircraft operations, the pilot-in- command shall advise the appropriate air traffic services unit as soon as practicable. Note. — Icing, turbulence and, to a large extent, wind shear are elements which, for the time being, cannot be satisfactorily observed from the ground and for which in most cases aircraft observations represent the only available evidence. 5.7 Reporting of aircraft observations during flight 5.7.1 Aircraft observations shall be reported by air-ground data link. Where air- ground data link is not available or appropriate, special and other non-routine aircraft observations during flight shall be reported by voice communications. 5.7.2 Aircraft observations shall be reported during flight at the time the observation is made or as soon thereafter as is practicable. 5.7.3 Routine and special Aaircraft observations shall be reported as routine and special air- reports., respectively. Routine and special air-reports reported by air-ground data link shall contain, as a minimum, the following meteorological information:a) wind direction; b) wind speed; c) air temperature; and d) condition prompting the issuance of the air-report (only applicable for special air- reports). 5.8 Relay of air-reports by air traffic services units 5.8.1 The meteorological authority concerned shall make arrangements with the appropriate ATS authority to ensure that, on receipt by the ATS units of: a) special air-reports by voice communications, the ATS units relay them without delay to their associated MWO; and b) Routine and special air-reports by data link communications, the ATS units relay them without delay to their associated MWO, the WAFCs and the centers designated by regional air navigation agreement for the operation of aeronautical fixed service Internet-based services. 5.8.2 Recommendation. — The meteorological authority concerned should make arrangements with the appropriate ATS authority to ensure that: a) special air-reports be uplinked for 60 minutes after their issuance; and b) information on wind and temperature included in automated special air-reports not be uplinked to other aircraft in flight. 5.9 Recording and post-flight reporting of aircraft observations of volcanic activity Special aircraft observations of pre-eruption volcanic activity, a volcanic eruption or volcanic ash cloud shall be recorded on the special air-report of volcanic activity form. A copy of the form shall be included with the flight documentation provided to flights operating on routes which, in the opinion of the meteorological authority concerned, could be affected by volcanic ash clouds. 5.9 Dissemination of air-reports 5.9.1 The meteorological watch office shall transmit without delay the special air-reports received by voice communications to the world area forecast centres (WAFCs) and the centres designated by regional air navigation agreement for the operation of aeronautical fixed service Internet-based services. 5.9.2 The meteorological watch office shall transmit without delay special air-reports of pre- eruption volcanic activity, a volcanic eruption or volcanic ash cloud received to the associated volcanic ash advisory centres. 5.9.3 When a special air-report is received at the meteorological watch office but the forecaster considers that the phenomenon causing the report is not expected to persist and, therefore,does not warrant issuance of a SIGMET, the special air-report shall be disseminated in the same way that SIGMET information is disseminated in accordance with 7.4.2.1, i.e. to meteorological watch offices, WAFCs, and other meteorological offices in accordance with regional air navigation agreement. Note. — The template used for special air-reports which are uplinked to aircraft in flight is in the PANSMET (Doc 10157), Appendix 3, Table A3-2. 5.9.4 Air-reports received at WAFCs shall be further disseminated as basic meteorological data. Note. — The dissemination of basic meteorological data is normally carried out on the World Meteorological Organization (WMO) Global Telecommunication System. 5.9.5 Recommendation. — Where supplementary dissemination of air-reports is required to satisfy special aeronautical or meteorological requirements, arrangements for such dissemination should be agreed between the meteorological authorities concerned. 5.9.6 Air-reports shall be exchanged in the format in which they are received.6. FORECASTS Note. — Please refer Appendix 5 of this CAR for technical specifications and detailed criteria. 6.1 Use of forecasts The issue of a new forecast by an aerodrome meteorological office, such as a routine aerodrome forecast, shall be understood to cancel automatically any forecast of the same type previously issued for the same place and for the same period of validity or part thereof. 6.2 Aerodrome forecasts meteorological forecast information 6.2.1 Aerodrome forecasts (TAF) Note. — Procedures and technical specifications related to this section are contained in the PANS-MET (Doc 10157), Section 4.1. 6.2.16.2.1.1 An aerodrome forecast shall be prepared, in accordance with regional air navigation agreement, by the aerodrome meteorological office designated by the meteorological authority concerned. Note. — The aerodromes for which aerodrome forecasts are to be prepared and the period of validity of these forecasts are listed in the relevant facilities and services implementation document (FASID) regional electronic air navigation plan (eANP), Volume II. 6.2.26.2.1.2 An aerodrome forecast shall be issued at a specified time not earlier than one hour prior to the beginning of its validity period and consist of a concise statement of the expected meteorological conditions at an aerodrome for a specified period. 6.2.36.2.1.3 Aerodrome forecasts and amendments thereto shall be issued as TAF and include the following information in the order indicated: a) identification of the type of forecast; b) location indicator; c) time of issue of forecast; d) identification of a missing forecast, when applicable; e) date and period of validity of forecast; f) identification of a cancelled forecast, when applicable; ga) surface wind; hb) visibility; ic) weather; jd) cloud; and ke) expected significant changes to one or more of these elements during the Period of validity.Optional elements shall be included in TAF in accordance with regional air navigation agreement. Note 1.— Technical specifications of the issuance of aerodrome forecast are contained in the PANSMET (Doc 10157) Chapter 4, 4.1.1.1 and 4.1.1.2. Note 2. — The visibility included in TAF refers to the forecast prevailing visibility. 6.2.46.2.1.4 Aerodrome meteorological offices preparing TAF shall keep the forecasts under continuous review and, when necessary, shall issue amendments promptly. The length of the forecast messages and the number of changes indicated in the forecast shall be kept to a minimum. Note. — Guidance on methods to keep TAF under continuous review is given contained in Chapter 3 of the Manual of Aeronautical Meteorological Practice (ICAO Doc 8896). 6.2.56.2.1.5 TAF that cannot be kept under continuous review shall be cancelled. 6.2.66.2.1.6 The period of validity of a routine TAF should be not less than 9 hours nor more than 30 hours; the period of validity should be determined by regional air navigation agreement. Routine TAF valid for less than 12 hours should be issued every 3 hours and those valid for 12 to 30 hours should be issued every 6 hours. 6.2.1.7 When issuing TAF, aerodrome meteorological offices shall ensure that not more than one TAF is valid at an aerodrome at any given time. 6.2.76.2.1.8 TAF and amendments thereto shall be disseminated to international OPMET databanks and the centres designated by regional air navigation agreement for the operation of aeronautical fixed service Internet-based services, in accordance with regional air navigation agreement. 6.36.2.2 Landing forecasts (trend forecasts) Note. — Procedures and technical specifications related to this section are contained in the PANS-MET (Doc 10157), Section 4.2. 6.3.16.2.2.1 A landing forecast shall be prepared by the aerodrome meteorological office designated by the meteorological authority concerned; as determined by regional air navigation agreement; such forecasts are intended to meet requirements of local users and of aircraft within about one hour’s flying time from the aerodrome. 6.3.26.2.2.2 Landing forecasts shall be prepared in the form of a trend forecast.6.2.2.3 A trend forecast shall consist of a concise statement of the expected significant changes in the meteorological conditions at that aerodrome to be appended to a local routine report, a local special report, METAR or SPECI. The period of validity of a trend forecast shall be 2 hours from the time of the report which forms part of the landing forecast. Note. — Technical specifications of the issuance of trend forecast are contained in the PANS- MET (Doc 10157) Chapter 4, 4.2.1.1 and 4.2.1.2. 6.3.36.2.2.4 The units and scales used in the trend forecast shall be the same as those used in the report to which it is appended. 6.46.2.3 Forecasts for take-off Note. — Procedures and technical specifications related to this section are contained in the PANS-MET (Doc 10157), Section 4.3. 6.4.16.2.3.1 A forecast for take-off shall be prepared by the aerodrome meteorological office designated by the meteorological authority concerned as agreed between the meteorological authority and operators concerned. 6.4.26.2.3.2 A forecast for take-off shall refer to a specified period of time and should contain information on expected conditions over the runway complex in regard to surface wind direction and speed and any variations thereof, temperature, pressure (QNH), and any other elements as agreed locally. 6.4.36.2.3.3 A forecast for take-off should be supplied to operators and flight crew Members on request within the 3 hours before the expected time of departure. 6.4.46.2.3.4 Aerodrome meteorological offices preparing forecasts for take-off should keep the forecasts under continuous review and, when necessary, should issue amendments promptly. 6.3 En-route meteorological forecast information 6.3.1 Forecasts by world area forecast centres Note. — Procedures and technical specifications related to this section are contained in the PANS-MET (Doc 10157), Section 5.1. Global upper-air gridded and significant weather forecasts shall be issued by world area forecast centres (WAFCs) in uniform formats and codes for the supply of such forecasts.6.56.3.2 Area forecasts for low-level flights (GAMET, and area forecasts in chart form) Note. — Procedures and technical specifications related to this section are contained in the PANS-MET (Doc 10157), Section 5.2. 6.5.16.3.2.1 When the density of traffic operating below flight level 100 (or up to flight level 150 in mountainous areas, or higher, where necessary) warrants the routine issue and dissemination of area forecasts for such operations, the frequency of issue, the form and the fixed time or period of validity of those forecasts, the dissemination and the criteria for amendments thereto shall be determined established by the meteorological authority in consultation with the users. 6.5.26.3.2.2 Intentionally left blank.When the density of traffic operating below flight level 100 warrants the issuance of AIRMET information in accordance with 7.5.1.1, area forecasts for such operations shall be prepared in a format as agreed between the meteorological authorities in the States concerned. When abbreviated plain language is used, the forecast shall be prepared as a GAMET area forecast; when chart form is used, the forecast shall be prepared as a combination of forecasts of upper wind and upper-air temperature, and of SIGWX phenomena. The area forecasts shall be issued to cover the layer between the ground and flight level 100 (or up to flight level 150 in mountainous areas, or higher, where necessary) and shall contain information on en-route weather phenomena hazardous to low-level flights, in support of the issuance of AIRMET information, and additional information required by low-level flights. Note. — Template of GAMET is contained in the PANS-MET (Doc 10157), Appendix 6, Table A6-1. 6.3.2.3 Intentionally left blank.Area forecasts for low-level flights prepared in support of the issuance of AIRMET information shall be issued every 6 hours for a period of validity of 6 hours and transmitted to meteorological watch offices and/or aerodrome meteorological offices concerned not later than one hour prior to the beginning of their validity period. 6.3.2.4 Area forecasts for low-level flights prepared in support of the issuance of AIRMET information shall be exchanged between aerodrome meteorological offices and/or meteorological watch offices responsible for the issuance of flight documentation for low-level flights in the flight information regions concerned. 6.3.2.5 Recommendation. — Area forecasts for low-level flights prepared in support of the issuance of AIRMET information should be disseminated to the aeronautical fixed service Internet-based services.Note. — Area forecasts for low-level flights in 6.3.2.4 and 6.3.2.5 are prepared in accordance with regional air navigation agreement, similar to the corresponding AIRMET information. 6.3.3 Forecasts by volcanic ash advisory centres Note. — Procedures and technical specifications related to this section are contained in the PANS-MET (Doc 10157), Section 5.3. When issuing forecasts of quantitative volcanic ash concentration information for a volcanic ash “cloud” in accordance with 3.5.2, volcanic ash advisory centres shall adopt uniform formats and codes for their supply. 6.5.37. SIGMET AND AIRMET INFORMATION, AERODROME WARNINGS AND WIND SHEAR WARNINGS AND ALERTS METEOROLOGICAL INFORMATION CONTAINING ADVISORIES, ALERTS, WARNINGS AND NOTICES Note. — Please refer Appendix 6 of this CAR for technical specifications and detailed criteria The Standards and Recommended Practices in this chapter are to be used in conjunction with the Procedures for Air Navigation Services — Meteorology (PANS-MET, Doc 10157), Chapter 6. 7.1 Volcanic ash advisory information and information from State volcano observatories Note. — Procedures and technical specifications related to this section are contained in the PANS-MET (Doc 10157), Section 6.1. 7.1.1 The advisory information on volcanic ash shall be issued by a volcanic ash advisory centre. 7.1.2 Recommendation.— Information on volcanic activity, and/or volcanic ash in the atmosphereshould be issued by a State volcano observatory as a Volcano Observatory Notice for Aviation (VONA). 7.2 Tropical cyclone advisory information Note.— Procedures and technical specifications related to this section are contained in the PANS-MET (Doc 10157), Section 6.2. The advisory information on tropical cyclones shall be issued by a tropical cyclone advisory centre. 7.3 Space weather advisory information Note.— Procedures and technical specifications related to this section are contained in the PANS-MET (Doc 10157), Section 6.3. The advisory information on space weather shall be issued by a global space weather centre (SWXC). Note.— Procedures and technical specifications related to this section are contained in the PANS-MET (Doc 10157), Section 6.4.7.4 SIGMET information 7.17.4.1 General provisions 7.4.1.1 SIGMET information shall be issued by a meteorological watch office and shall give a concise description in abbreviated plain language concerning the occurrence and/or expected occurrence of specified en-route weather and other phenomena in the atmosphere that may affect the safety of aircraft operations, and of the development of those phenomena in time and space. One of the following phenomena shall be included in SIGMET information: 1) thunderstorm; 2) tropical cyclone; 3) turbulence; 4) icing; 5) mountain wave; 6) duststorm; 7) sandstorm; 8) volcanic ash; and 7.1.1 9) radioactive cloud. 7.1.27.4.1.2 SIGMET information shall be cancelled when the phenomena are no longer occurring or are no longer expected to occur in the area. 7.1.37.4.1.3 The period of validity of a SIGMET message information shall be not more than 4 hours. In the special case of SIGMET messages information for volcanic ash cloud and tropical cyclones, the period of validity shall be extended up to 6 hours. 7.1.47.4.1.4 SIGMET messages information concerning volcanic ash cloud and tropical cyclones should be based on advisory information provided by VAACs and TCACs, respectively, designated by regional air navigation agreement. 7.1.57.4.1.5 Close coordination shall be maintained between the meteorological watch office and the associated area control Centre/flight information Centre to ensure that information on volcanic ash included in SIGMET and NOTAM messages is consistent. 7.4.1.6 SIGMET messages information shall be issued not more than 4 hours before the commencement of the period of validity. In the special case of SIGMET messages information for volcanic ash cloud and tropical cyclones, these messages this information shall Be issued as soon as practicable but not more than 12 hours before the commencement of the period of validity. SIGMET messages information for volcanic ash and tropical cyclones shall be updated at least every 6 hours.7.4.1.7 Recommendation.— In cases where the airspace is divided into an FIR and an upper flight information region (UIR), the SIGMET should be identified by the location indicator of the air traffic services unit serving the FIR. 7.1.6 Note.— SIGMET information applies to the whole airspace within the lateral limits of the FIR, i.e. to the FIR and to the UIR. The particular areas and/or flight levels affected by the meteorological phenomena prompting the issuance of the SIGMET are included in SIGMET information. 7.4.2 Dissemination of SIGMET information 7.4.2.1 SIGMET information shall be disseminated to meteorological watch offices, WAFCs and to other meteorological offices in accordance with regional air navigation agreement. SIGMET information for volcanic ash shall also be disseminated to volcanic ash advisory centres. 7.4.2.2 SIGMET information shall be disseminated to international OPMET databanks and the centres designated by regional air navigation agreement for the operation of aeronautical fixed service Internet-based services, in accordance with regional air navigation agreement. 7.27.5 AIRMET Information Intentionally left blank. 7.37.6 Aerodrome warnings Note.— Procedures and technical specifications related to this section are contained in the PANS-MET (Doc 10157), Section 6.6. 7.6.1 General Provisions 7.6.1.1 Aerodrome warnings shall be issued by the aerodrome meteorological office designated by the meteorological authority concerned and shall give concise information of meteorological conditions which could adversely affect aircraft on the ground, including parked aircraft, and the aerodrome facilities and services. Note. — Template of aerodrome warnings is contained in the PANS-MET (Doc 10157), Appendix 7, Table A7-6. 7.6.1.2 Recommendation.— Aerodrome warnings should relate to the occurrence or expected occurrence of one or more of the following phenomena: — tropical cyclone (to be included if the 10-minute mean surface wind speed at the aerodrome is expected to be 17 m/s (34 kt) or more) — thunderstorm— hail — snow (including the expected or observed snow accumulation) — freezing precipitation — frost — hoar frost or rime — sandstorm — duststorm — rising sand or dust — strong surface wind and gusts — squall — volcanic ash (including volcanic ash deposition) — tsunami — toxic chemicals 7.3.1 — other phenomena as agreed locally. Note.— Aerodrome warnings related to the occurrence or expected occurrence of tsunami are not required where a national public safety plan for tsunami is integrated with the “at risk” aerodrome concerned. 7.6.1.3 Aerodrome warnings shall be cancelled when the conditions are no longer occurring and/ or no longer expected to occur at the aerodrome. 7.6.2 Dissemination of aerodrome warnings 7.3.2 Aerodrome warnings shall be disseminated in accordance with local arrangements to those concerned. 7.7 Wind shear warnings and alerts Note.— Procedures and technical specifications related to this section are contained in the PANS-MET (Doc 10157), Section 6.7. 7.47.7.1 General provisions Note. — Guidance on the subject is contained in the Manual on Low-level Wind Shear (Doc 9817). Wind shear alerts are expected to complement wind shear warnings and together are intended to enhance situational awareness of wind shear. 7.4.17.7.1.1 Wind shear warnings shall be prepared issued by the concerned aerodrome meteorological office and shall give concise information of the observed wind shear which could adversely affect aircraft on the approach path or take-off path or during circling approach. for aerodromes where wind shear is considered a factor, in accordance with local arrangements with the appropriate air traffic services unit and the operators concerned. Wind shear warnings shall give concise information on theobserved or expected existence of wind shear which could adversely affect aircraft on the approach path or take-off path or during circling approach between runway level and 500 m (1 600 ft) above that level and aircraft on the runway during the landing roll or take-off run. Where local topography has been shown to produce significant wind shears at heights in excess of 500 m (1 600 ft) above runway level, then 500 m (1 600 ft) shall not be considered restrictive. Note.— Template of wind shear warnings is contained in the PANS-MET (Doc 10157), Appendix 7,Table A7-7. 7.4.27.7.1.2 Wind shear warnings for arriving aircraft and/or departing aircraft should be cancelled when aircraft reports indicate that wind shear no longer exists, or alternatively, after two hours elapsed time. The criteria for the cancellation of a wind shear warning should be defined locally for each aerodrome, as agreed between the meteorological authority service provideer, the appropriate ATS authority and the operators concerned. 7.4.37.7.1.3 At aerodromes where wind shear is detected by automated, ground-based, wind shear remote-sensing or detection equipment, wind shear alerts generated by these systems shall be issued. Wind shear alerts shall give concise, up-to-date information related to the observed existence of wind shear involving a headwind/tailwind change of 7.5 m/s (15 kt) or more which could adversely affect aircraft on the final approach path or initial take-off path and aircraft on the runway during the landing roll or take-off run. Wind shear alerts issued in accordance with para 7.4.3 should be updated at Least every minute. The wind shear alert should be cancelled as soon as the headwind/tailwind change falls below 7.5 m/s (15 kt). 7.7.2 Dissemination of wind shear warnings and alerts 7.7.2.1 The wind shear warnings shall be disseminated in accordance with local arrangements to those concerned. 7.4.47.7.2.2 7.7.2.2 The wind shear alerts shall be disseminated from automated, ground-based, wind shear remote-sensing or detection equipment in accordance with local arrangements to those concerned.8. AERONAUTICAL CLIMATOLOGICAL INFORMATION Note1.— Please refer Appendix 7 of this CAR for technical specifications and detailed criteria. The Standards and Recommended Practices in this chapter are to be used in conjunction with the Procedures for Air Navigation Services — Meteorology (PANS-MET, Doc 10157), Chapter 7. 8.1 General provisions Note 1.— Procedures and technical specifications related to this section are contained in the PANS-MET (Doc 10157), Section 7.1. Note 2. — In cases where it is impracticable to meet the requirements for aeronautical climatological information on a national basis, the collection, processing and storage of observational data may be effected through computer facilities available for international use, and the responsibility for the preparation of the required aeronautical climatological information may be delegated as agreed between the meteorological authorities concerned. 8.1.1 Aeronautical climatological information required for the planning of flight operations shall be prepared in the form of aerodrome climatological tables and aerodrome climatological summaries. Such information shall be supplied to aeronautical users as agreed between the meteorological authorityservice provider and the users concerned. Note. — Climatological data required for aerodrome planning purposes are set out in CAR Section 4 Series B Part I para.3.1.4 & Attachment A. 8.1.2 Aeronautical climatological information shall normally be based on observations made over a period of at least five years and the period should be indicated in the information supplied. 8.1.3 Climatological data related to sites for new aerodromes and to additional runways at existing aerodromes should be collected starting as early as possible before the commissioning of those aerodromes or runways. 8.2 Aerodrome climatological tables Note.— Procedures and technical specifications related to this section are contained in the PANS-MET (Doc 10157), Section 7.2. IMD should make arrangements for collecting and retaining the necessary observational data and have the capability: a) a) to prepare aerodrome climatological tables for each regular and alternate international aerodrome within its territory; andb) b) to make available such climatological tables to an aeronautical user within a time period as agreed between the meteorological authority service provider and that the user concerned. 8.3 Aerodrome climatological summaries Note.— Procedures and technical specifications related to this section are contained in the PANS-MET (Doc 10157), Section 7.3. Aerodrome climatological summaries should follow the procedures prescribed by the World Meteorological Organization (WMO). Where computer facilities are available to store, process and retrieve the information, the summaries should be published, or otherwise made available to aeronautical users on request. Where such computer facilities are not available, the summaries should be prepared using the models specified by the WMO, and should be published and kept up to date as necessary. 8.4 Copies of meteorological observational data Each meteorological authority, on request and to the extent practicable, shall make available to any other meteorological authority, to operators and to others concerned with the application of meteorology to international air navigation, meteorological observational data required for research, investigation or operational analysis. 8.5 Exchange of aeronautical climatological information Recommendation.— Aeronautical climatological information should be exchanged on request between meteorological authorities. Operators and other aeronautical users desiring such information should contact the meteorological service provider responsible for its preparation.9. METEOROLOGICAL SERVICE FOR OPERATORS AND FLIGHT CREW MEMBERS Note. — Please refer Appendix 8 of this CAR for technical specifications and detailed criteria The Standards and Recommended Practices in this chapter are to be used in conjunction with the Procedures for Air Navigation Services — Meteorology (PANS-MET, Doc 10157), Chapter 8. 9.1 General provisions Note.— Procedures and technical specifications related to this section are contained in the PANS-MET (Doc 10157), Section 8.1. 9.1.1 Meteorological information shall be supplied to operators and flight crew members for: a) pre-flight planning by operators; b) in-flight re-planning by operators using centralized operational control of flight operations; c) use by flight crew members before departure; and d) Aircraft in flight. 9.1.2 The meteorological service provider, in consultation with the operator, shall determine: a) the type and format of meteorological information to be supplied; and b) methods and means of supplying that information. 9.1.29.1.3 Meteorological information supplied to operators and flight crew members shall cover the flight in respect of time, altitude and geographical extent. Accordingly, the information shall relate to appropriate fixed times, or periods of time, and shall extend to the aerodrome of intended landing, also covering the meteorological conditions expected between the aerodrome of intended landing and one alternate aerodrome designated by the operator. 9.1.39.1.4 Meteorological information supplied to operators and flight crew members shall be up to date and include the following information, a) aerodrome and en-route observational information; and b) aerodrome and en-route forecast information. a) Forecasts of 1) upper wind and upper-air temperature; 2) upper-air humidity; 3) geopotential altitude of flight levels; 4) flight level and temperature of tropopause; 5) direction, speed and flight level of maximum wind; 6) SIGWX phenomena; and 7) Cumulonimbus clouds, icing and turbulence.Note 1. — Forecasts of upper-air humidity and geopotential altitude of flight levels are used only in automatic flight planning and need not be displayed. Note 2. — Forecasts of cumulonimbus cloud, icing and turbulence are intended to be processed and, if necessary, visualized according to the specific thresholds relevant to user operations. b) METAR or SPECI (including trend forecasts as issued in accordance with regional air navigation agreement) for the aerodromes of departure and intended landing, and for take-off, en-route and destination alternate aerodromes; c) TAF or amended TAF for the aerodromes of departure and intended landing, and for take-off, en-route and destination alternate aerodromes; d) forecasts for take-off; e) SIGMET information and appropriate special air-reports relevant to the whole route; Note. — Appropriate special air-reports will be those not already used in the preparation of SIGMET. f) volcanic ash and tropical cyclone advisory information relevant to the whole route; g) as determined by regional air navigation agreement, GAMET area forecast and/or area forecasts for low-level flights in chart form prepared in support of the issuance of AIRMET information, and AIRMET information for low- level flights relevant to the whole route; h) aerodrome warnings for the local aerodrome; i) meteorological satellite images; j) ground-based weather radar information; and c) Space weather advisory information relevant to the whole route. k) Note.— The list of meteorological information to be supplied to operators and flight crew members is contained in the PANS-MET (Doc 10157), 8.1.1.2. 9.1.49.1.5 FEn-route forecasts listed under 9.1.3 a) information shall be generated from the digital forecasts provided by the WAFCs whenever these forecasts cover the intended flight path in respect of time, altitude and geographical extent, unless otherwise agreed between the meteorological authority service provider and the operator concerned. 9.1.59.1.6 When forecasts are identified as being originated by the WAFCs, no modifications shall be made to their meteorological content. 9.1.6 Charts generated from the digital forecasts provided by the WAFCs shall be made available, as required by operators, for fixed areas of coverage as shown in Appendix 8 of this CAR, Figures A8-1, A8-2 and A8-3.9.1.7 When forecasts of upper wind and upper-air temperature listed under 9.1.3 a) 1) Are supplied in chart form, they shall be fixed time prognostic charts for flight levels as specified in Appendix 2 1.2.2 a). When forecasts of SIGWX phenomena listed under 9.1.3 a) 6) are supplied in chart form, they shall be fixed time prognostic charts for an atmospheric layer limited by flight levels as specified in Appendix 2, 1.3.2 and Appendix 5, 4.3.2. 9.1.7 The forecasts of upper wind and upper-air temperature and of SIGWX phenomena above flight level 100 requested for pre-flight planning and in- flight re-planning by the operator shall be supplied as soon as they become available, but not later than 3 hours before departure. Other meteorological Information requested for pre-flight planning and in-flight re-planning by the operator shall be supplied as soon as is practicable. 9.1.8 Recommendation.— Meteorological information for pre-flight planning and in-flight replanning by operators of helicopters flying to offshore structures should include data covering the layers from sea level to flight level 100. 9.1.9 When necessary, IMD shall initiate coordinating action with the meteorological authorities of other States with a view to obtaining from them the reports and/or forecasts required. 9.1.10 Meteorological information shall be supplied to operators and flight crew members at the location to be determined by the IMD, after consultation with the operators concerned and at the time agreed between the aerodrome meteorological office and the operator concerned. The service for pre-flight planning shall be confined to flights originating within India. At an aerodrome without an aerodrome meteorological office at the aerodrome, arrangements for the supply of meteorological information shall be as agreed between IMD and the operator concerned. 9.2 Briefing, consultation and display Note.— The requirements for the use of automated pre-flight information systems in providing briefing, consultation and display are given contained in 9.4. 9.2.1 Briefing and/or consultation shall be provided, on request, to flight crew members and/or other flight operations personnel. Its purpose shall be to supply the latest available information on existing and expected meteorological conditions along the route to be flown, at the aerodrome of intended landing, alternate aerodromes and other aerodromes as relevant, either to explain and amplify the information contained in the flight documentation or, as agreed between IMD and the operator concerned, in lieu of flight documentation. 9.2.2 Meteorological information used for briefing and consultation shall include any or all of the information listed in 9.1.34. 9.2.3 If the aerodrome meteorological office expresses an opinion on the development of the meteorological conditions at an aerodrome which differs appreciably from the aerodromeforecast included in the flight documentation, the attention of flight crew members shall be drawn to the divergence. The portion of the briefing dealing with the divergence shall be recorded at the time of briefing and this record shall be made available to the operator. 9.2.4 The required briefing, consultation, display and/or flight documentation shall normally be provided by the aerodrome meteorological office associated with the aerodrome of departure. At an aerodrome where these services are not available, arrangements to meet the requirements of flight crew members shall be as agreed between the meteorological authority service provider and the operator concerned. In exceptional circumstances, such as an undue delay, the aerodrome meteorological office associated with the aerodrome shall provide or, if that is not practicable, arrange for the provision of a new briefing, consultation and/ or flight documentation as necessary. 9.2.5 The flight crew member or other flight operations personnel for whom briefing, consultation and/or flight documentation has been requested should visit the aerodrome meteorological office at the time agreed between the aerodrome meteorological office and the operator concerned. Where local Circumstances at an aerodrome make personal briefing or consultation impracticable, the aerodrome meteorological office should provide those services by telephone or other suitable telecommunications facilities. 9.2.59.2.6 Recommendation.— The material displayed should be readily accessible to the flight crewmembers or other flight operations personnel concerned. 9.3 Flight documentation Note 1. — Procedures and technical specifications related to this section are contained in the PANS-MET (Doc 10157), Section 8.2. Note 2. — The requirements for the use of automated pre-flight information systems in providing flightdocumentation are given contained in 9.4. 9.3.1 Flight documentation to be made available shall comprise information listed under 9.1.34 a) 1) and 6), b), c), e), f) and, if appropriate, g) and k). However, flight documentation for flights of two hours’ duration or less, after a short stop or turnaround, shall be limited to the information operationally needed, as agreed between the meteorological authority and operator concerned, but in all cases the flight documentation shall at least comprise information on 9.1.3 b), c), e), f) and, if appropriate, g) and k). 9.3.2 Whenever it becomes apparent that the meteorological information to be included in the flight documentation will differ materially from that made available for pre-flight planning and in-flight re-planning, the operator shall be advised immediately and, if practicable, be supplied with the revised information as agreed between the operator and the aerodrome meteorological office concerned. 9.3.3 In cases where a need for amendment arises after the flight documentation has beensupplied, and before take-off of the aircraft, the aerodrome meteorological office should, as agreed locally, issue the necessary amendment or updated information to the operator or to the local ATS unit, for transmission to the aircraft. 9.3.4 Recommendation.— The flight documentation related to concatenated route-specific upper wind and upper-air temperature forecasts should be provided as agreed between the meteorological service provider and the operator concerned. Note.— Guidance on the design, formulation and use of concatenated charts is contained in the Manual of Aeronautical Meteorological Practice (Doc 8896). 9.3.5 Meteorological information received from other meteorological offices shall be included in flight documentation without change modification. 9.3.6 Recommendation.— Charts included in flight documentation should have a high standard ofclarity and legibility. 9.3.3 Note.— The details of the characteristics of charts to be included in flight documentation are contained the Procedures for Air Navigation Services – Meteorology (PANS-MET, Doc 10157), Section 8.2.3.1. 9.3.7 The IMD shall retain ensure that the meteorological service provider retains information supplied to flight crew members, either as printed copies or in computer files, for a period of at least 30 days from the date of issue. This information shall be made available, on request, for inquiries or investigations and, for these purposes, shall be retained until the inquiry or investigation is completed. 9.3.4 9.4 Automated pre-flight information systems for briefing, consultation, flight planning and flight documentation Note.— Procedures and technical specifications related to this section are contained in the PANS-MET (Doc 10157), Section 8.3. 9.4.1 Where IMD uses automated pre-flight information systems to supply and display meteorological information to operators and flight crew members for self-briefing, flight planning and flight documentation purposes, the information supplied and displayed shall comply with the relevant provisions in 9.1 to 9.3 inclusive. 9.4.2 Automated pre-flight information systems providing for a harmonized, common point of access to meteorological information and aeronautical information services information by operators, flight crew members and other aeronautical personnel concerned should be as agreed between the meteorological authority service provider and the civil aviationauthority or the agency to which the authority to provide service has been delegated in accordance with CAR Section 9, Series ‘I’, Part- I, Para 2.1.1. Note. — The meteorological and aeronautical information services information Concerned is specified in 9.1 to 9.3 and Appendix 8 in the PANS-MET (Doc 10157),Chapter 8 and in CAR Section 9, Series ‘I’, Part-I, Para 8.1 and 8.2, respectively. 9.4.3 Where automated pre-flight information systems are used to provide for a harmonized, common point of access to meteorological information and aeronautical information services information by operators, flight crew members and other aeronautical personnel concerned, IMD shall remain responsible for ensuring that the quality control and quality management of meteorological information are provided by the meteorological service provider by means of such systems in accordance with para 2.2.2. Note. — The responsibilities relating to aeronautical information services information and the quality assurance of the information are given contained in CAR Section 9, Series ‘I’ Part 1 Para 1, 2 and 3. 9.4.4 Automated pre-flight information systems providing self-briefing facilities shall provide for access by operators and flight crew members to consultation, as necessary, with an aerodrome meteorological office by telephone or other suitable telecommunications means. 9.5 Meteorological Iinformation for aircraft in flight Note.— Procedures and technical specifications related to this section are contained in the PANS-MET (Doc 10157), Section 8.4. 9.5.1 Meteorological information for use by aircraft in flight shall be supplied by an aerodrome meteorological office or MWO to its associated ATS unit and through D-VOLMET or VOLMET broadcasts. Meteorological information for planning by the operator for aircraft in flight shall be supplied on request, as agreed between meteorological authority or authorities and the operator concerned. 9.5.2 Meteorological information for use by aircraft in flight shall be supplied to ATS units in accordance with the specifications of para 10. 9.5.29.5.3 Recommendation.— If an aircraft in flight requests meteorological information, the aerodrome meteorological office or meteorological watch office which receives the request should arrange to supply the information with the assistance, if necessary, of another aerodrome meteorological office ormeteorological watch office. 9.5.39.5.4 Meteorological information shall be supplied through D-VOLMET or VOLMET broadcasts as determined by regional air navigation agreement, and in accordance with the specifications of para 11.10. METEOROLOGICAL INFORMATION FOR AIR TRAFFIC SERVICES, SEARCH AND RESCUE SERVICES AND AERONAUTICAL INFORMATION SERVICES Note. — Please refer Appendix 9 of this CAR for Technical specifications and detailed criteria The Standards and Recommended Practices in this chapter are to be used in conjunction with the Procedures for Air Navigation Services — Meteorology (PANS-MET, Doc 10157), Chapter 9. 10.1 Information for air traffic services units Note.— Procedures and technical specifications related to this section are contained in the PANS-MET (Doc 10157), Section 9.1. 10.1.1 General 10.1.110.1.1.1 IMD shall designate an aerodrome meteorological office or MWO to be associated with each ATS unit. The associated aerodrome meteorological office or MWO shall, after coordination with the ATS unit, supply, or arrange for the supply of up-to-date meteorological information to the unit as necessary for the conduct of its functions. 10.1.210.1.1.2 An aerodrome meteorological office should be associated with an aerodrome control tower or approach control unit for the provision of meteorological information. 10.1.310.1.1.3 A MWO shall be associated with a FIC or an ACC for the provision of Meteorological information. 10.1.410.1.1.4 Where, owing to local circumstances, it is convenient for the duties of an associated aerodrome meteorological office or MWO to be shared between two or more aerodrome meteorological offices or MWO, the division of responsibility should be determined by the meteorological authority service provider in consultation with the appropriate ATS authority. 10.1.510.1.1.5 Any meteorological information requested by an ATS unit in connection with an aircraft emergency shall be supplied as rapidly as possible. 10.1.2 Supply, dissemination and transmission arrangements 10.1.2.1 Where necessary for flight information purposes, current meteorological reports and forecasts shall be supplied to designated aeronautical telecommunication stations. A copy of such information shall be forwarded, if required, to the FIC or ACC.10.1.2.2 Recommendation.— When computer-processed upper-air grid point data in digital form is made available to air traffic services units for use by air traffic services computers the transmission arrangements should be as agreed between the meteorological service provider and the appropriate ATS authority. The data should be supplied as soon as is practicable after the processing of the forecasts has been completed. 10.2 Information for search and rescue services units 10.210.2.1 General Aerodrome meteorological offices or MWO designated by the meteorological authority in accordance with regional air navigation agreement shall supply search and rescue services units with the meteorological information they require in a form established by mutual agreement. For that purpose, the designated aerodrome meteorological office or MWO shall maintain liaison with the search and rescue services unit throughout a search and rescue operation. 10.2.2 List of information Information to be supplied to rescue coordination centres shall include the meteorological conditions that existed in the last known position of a missing aircraft and along the intended route of that aircraft with particular reference to: a) significant en-route weather phenomena; b) cloud amount and type, particularly cumulonimbus; height indications of bases and tops; c) visibility and phenomena reducing visibility; d) surface wind and upper wind; e) state of ground, in particular, any snow cover or flooding; f) sea-surface temperature, state of the sea, ice cover if any and ocean currents, if relevant to the search area; and g) sea-level pressure data. 10.3 Information for aeronautical information services units 10.310.3.1 General The meteorological authority, in coordination with the appropriate civil aviation authority, shall arrange for the supply by the meteorological service provider concerned of up-to-date meteorological information to relevant aeronautical information services units, as necessary, for the conduct of their functions.10.3.2 List of information The following information shall be supplied, as necessary, to an aeronautical information services unit: a) information on meteorological service for international air navigation, intended for inclusion in the aeronautical information publication(s) concerned; Note. — Details of this information are contained in the Procedures for Air Navigation Services — Aeronautical Information Management (PANS-AIM, Doc 10066), Appendix 3, Part 1, GEN 3.5 and Part 3, AD 2.2, 2.11, 3.2 and 3.11. b) information necessary for the preparation of NOTAM or ASHTAM including, in particular, information on: 1) the establishment, withdrawal and significant changes in operation of aeronautical meteorological services. This information is required to be provided to the aeronautical information services unit sufficiently in advance of the effective date to permit issuance of NOTAM in compliance with Annex 15, 6.3.2.2 and 6.3.2.3; 2) the occurrence of volcanic activity; and Note.— The specific information required is contained in Annex 3, Chapter 3, 3.3.2 h) and Chapter 4, 4.8. 3) release of radioactive materials into the atmosphere, as agreed between the meteorological and appropriate civil aviation authorities concerned; and Note.— The specific information required is contained in Annex 3, Chapter 3, 3.4.2 g). c) information necessary for the preparation of aeronautical information circulars including, in particular, information on: 1) expected important changes in aeronautical meteorological procedures, services and facilities provided; and 2) effect of certain weather phenomena on aircraft operations.11. REQUIREMENTS FOR AND USE OF COMMUNICATIONS TO EXCHANGE METEOROLOGICAL INFORMATION Note 1. — Technical specifications and detailed criteria related to this Para are given in Appendix 10 of this CAR The Standards and Recommended Practices in this chapter are to be used in conjunction with the Procedures for Air Navigation Services — Meteorology (PANS-MET, Doc 10157), Chapter 10.. Note 2. — It is recognized that it is for each Contracting State to decide upon its own internal organization and responsibility for implementing the telecommunications facilities referred to in this Para. 11.1 Requirements for communications 11.1.1 Suitable telecommunications facilities shall be made available to permit aerodrome meteorological offices and, as necessary, aeronautical meteorological stations to supply the required meteorological information to ATS units on the aerodromes for which those offices and stations are responsible, and in particular to aerodrome control towers, approach control units and the aeronautical telecommunications stations serving these aerodromes. 11.1.2 Suitable telecommunications facilities shall be made available to permit MWO to supply the required meteorological information to ATS and search and rescue services units in respect of the FIR, control areas and search and rescue regions for which those offices are responsible, and in particular to FIC, ACC and rescue coordination Centre’s and the associated aeronautical Telecommunications stations. 11.1.3 Suitable telecommunications facilities shall be made available to permit WAFC to supply the required WAFS products forecasts to aerodrome meteorological offices, meteorological authorities service providers and other users. 11.1.4 Telecommunications facilities between aerodrome meteorological offices and, as necessary, aeronautical meteorological stations and aerodrome control towers or approach control units shall permit communications by direct speech, the speed with which the communications can be established being such that the required points may normally be contacted within approximately 15 seconds. 11.1.5 Telecommunications facilities between aerodrome meteorological offices or meteorological offices and FIC, ACC, rescue coordination centres and aeronautical telecommunications stations should permit: a) communications by direct speech, the speed with which the communications can be established being such that the required points may normally be contacted within approximately 15 seconds; and b) Printed communications, when a record is required by the recipients; the messagetransit time should not exceed 5 minutes. Note. — In 11.1.4 and 11.1.5, “approximately 15 seconds” refers to telephony communications involving switchboard operation and “5 minutes” refers to printed communications involving retransmission. 11.1.6 The telecommunications facilities required in accordance with Para 11.1.4 and 11.1.5 should be supplemented, as and where necessary, by other forms of visual or audio communications, for example, closed-circuit television or separate information processing systems. 11.1.7 As agreed between the meteorological authority service provider and the operators concerned, provision should be made to enable operators to establish suitable telecommunications facilities for obtaining meteorological information from aerodrome meteorological offices or other appropriate sources. 11.1.8 Suitable telecommunications facilities shall be made available to permit meteorological offices to exchange operational meteorological information with other meteorological offices. 11.1.9 The telecommunications facilities used for the exchange of operational meteorological information should be the aeronautical fixed service or, for the exchange of non-time critical operational meteorological information, the public Internet, subject to availability, satisfactory operation and bilateral/multilateral and/or regional air navigation agreements. 11.1.10 Recommendation.— When upper-air grid point data in digital form is made available for use by air traffic services computers, the transmission arrangements should be as agreed between the meteorological service provider and the appropriate ATS authority. 11.1.911.1.11 Recommendation.— When upper-air grid point data in digital form is made available to operators for flight planning by computer, the transmission arrangements should be as agreed between the world area forecast centre concerned, the meteorological service provider and the operators concerned. Note 1. — Aeronautical fixed service Internet-based services, operated by the WAFC, providing for global coverage are used to support the global exchanges of operational meteorological information. Note 2. — Guidance material on non-time-critical operational meteorological Information and relevant aspects of the public Internet is provided in the Guidelines on the Use of the Public Internet for Aeronautical Applications (Doc 9855).11.2 Use of aeronautical fixed service communications and public Internet - Meteorological bulletins Note.— Procedures and technical specifications related to this section are contained in the PANS-MET (Doc 10157), Section 10.1. The Meteorological bulletins containing operational meteorological information to be transmitted via the aeronautical fixed service or public Internet shall be originated by the appropriate meteorological office or aeronautical meteorological station. Note. — Meteorological bulletins containing operational meteorological information authorized for transmission via the aeronautical fixed service are listed in CAR Section 9, Series ‘D’, Part 3, Para 4 together with the relevant priorities and priority indicators. 11.2.1 Meteorological bulletins 11.2.1.1 Meteorological bulletins containing operational meteorological information to be transmitted via the aeronautical fixed service or the public Internet shall be originated by the appropriate meteorological office or aeronautical meteorological station. Note.— Meteorological bulletins containing operational meteorological information authorized for transmission via the aeronautical fixed service are listed in Annex 10, Volume II, Chapter 4, together with the relevant priorities and priority indicators. 11.2.1.2 Messages and bulletins containing operational meteorological information shall achieve transit times of less than 5 minutes, unless otherwise determined to be lower by regional air navigation agreement. 11.2.2 Use of aeronautical fixed service communications -– World AareaFforecast S system products forecasts 11.2.2.1 Recommendation.— The telecommunications facilities used for the supply of WAFS forecasts should be the aeronautical fixed service or the public Internet. 11.311.2.2.2 World area forecast system WAFS products in digital form forecasts should be transmitted using binary digital data communications techniques. The method and channels used for the dissemination of the products forecasts should be as determined by regional air navigation agreement. 11.411.3 Use of aeronautical mobile service communications Note.— Procedures and technical specifications related to this section are contained in thePANS-MET (Doc 10157), Section 10.2. The content and format of meteorological information transmitted to aircraft and by aircraft shall be consistent with the provisions of this CAR. 11.511.4 Intentionally left blank. 11.611.5 Use of aeronautical broadcasting service — contents of VOLMET broadcasts Note.— Procedures and technical specifications related to this section are contained in the PANS-MET (Doc 10157), Section 10.4. 11.6.111.5.1 Continuous VOLMET broadcasts, normally on very high frequencies (VHF), shall contain current METAR and SPECI, together with trend forecasts where available. 11.6.211.5.2 Scheduled VOLMET broadcasts, normally on high frequencies (HF), shall contain current METAR and SPECI, together with trend forecasts where available and, where so determined by regional air navigation agreement, TAF and SIGMET.APPENDICES APPENDIX 1. FLIGHT DOCUMENTATION – MODEL CHARTS AND FORMS (See Para 9 of this CAR) MODEL A OPMET information MODEL IS Upper wind and upper-air temperature chart for standard isobaric surface Example 1. Arrows, feathers and pennants (Mercator projection) Example 2. Arrows, feathers and pennants (Polar stereographic projection) MODEL SWH Significant weather chart (high level) Example. Polar stereographic projection (showing the jet stream vertical extent) MODEL SWM Significant weather chart (medium level) MODEL SWL Significant weather chart (low level) Example 1 Example 2 MODEL TCG Tropical cyclone advisory information in graphical format MODEL VAG Volcanic ash advisory information in graphical format Example 1. Mercator projection Example 2. Polar stereographic projection MODEL STC SIGMET for tropical cyclone in graphical format MODEL SVA SIGMET for volcanic ash in graphical format Example 1. Mercator projection Example 2. Polar stereographic projection MODEL SGE SIGMET for phenomena other than tropical cyclone and volcanic ash in graphical format MODEL SN Sheet of notations used in flight documentationAPPENDIX 2. TECHNICAL SPECIFICATIONS RELATED TO GLOBALSYSTEMS, SUPPORTING CENTRES AND METEOROLOGICAL OFFICES (See Para 3 of this CAR) 1. World Area Forecast System (WAFS) The technical specifications related to World Area Forecast System (WAFS) are stipulates in Appendix 2 of ICAO Annex 3 for the contracting states which have accepted responsibilities for providing a World Area Forecast Centers (WAFC). India is not a WAFC. However, the Service Provider shall have to be familiar with the technical specifications so as to be able to interact with them and use its products/services effectively. 1.1 Formats and codes Intentionally left blank 1.2 Upper-air gridded forecasts 1.2.1 The forecasts of upper winds; upper-air temperature; and humidity; direction, speed and flight level of maximum wind; flight level and temperature of tropopause, areas of cumulonimbus clouds, icing, turbulence, and geopotential altitude of flight levels shall be prepared four times a day by a WAFC and shall be valid for fixed valid times at 6, 9, 12, 15, 18, 21, 24, 27, 30, 33 and 36 hours after the time (0000, 0600, 1200 and 1800 UTC) of the synoptic data on which the forecasts were based. Each forecast disseminated as soon as technically feasible as but not later than 5 hours after standard time of observation. 1.2.2 The grid point forecasts prepared by a WAFC shall comprise: (a) wind and temperature data for flight levels 50 (850 hPa), 80 (750 hPa), 100 (700 hPa), 140 (600 hPa), 180 (500 hPa), 210 (450 hPa), 240 (400 hPa), 270 (350 hPa), 300 (300 hPa), 320 (275 hPa),340 (250 hPa), 360 (225 hPa), 390 (200 hPa), 410 (175 hPa), 450 (150 hPa), 480 (125 hPa) and 530 (100 hPa); (b) flight level and temperature of tropopause; (c) direction, speed and flight level of maximum wind; (d) humidity data for flight levels 50 (850 hPa), 80 (750 hPa), 100 (700 hPa), 140 (600 hPa) and180 (500 hPa); (e) horizontal extent and flight levels of base and top of cumulonimbus clouds; (f) icing for layers centered at flight levels 60 (800 hPa), 100 (700 hPa), 140 (600 hPa), 180 (500hPa), 240 (400 hPa) and 300 (300 hPa);Note-Layers centred at a flight level referred to in (f) have a depth of 100hPa (g) Turbulence for layers centered at flight levels 100 (700 hPa), 140 (600 hPa), 180(500 hPa) 240 (400 hPa), 270 (350 hPa), 300 (300 hPa), 340 (250 hPa), 390 (200 hPa) and 450 (150 hPa); and Note .1— Layers centred at a flight level referred to in g) and h) have a depth of 100 hPa for flight levels below 240, then 50 hPa for flight levels 240 and above. Note 2 turbulence referred to in g) above encompasses all types of turbulence, including clear-air and in-cloud turbulence. (h) Geopotential altitude data for flight levels 50 (850 hPa), 80 (750 hPa), 100 (700 hPa), 140 (600 hPa), 180 (500 hPa), 210 (450 hPa), 240 (400 hPa), 270 (350 hPa), 300 (300 hPa), 320 (275 hPa), 340 (250 hPa), 360 (225 hPa), 390 (200 hPa), 410 (175 hPa), 450 (150 hPa), 480 (125 hPa) and 530 (100 hPa). Note –the exact pressure levels (hPa) for (a), (d), (f), (g) and (h) are provided in the manual of aeronautical meteorological practice (Doc 8896). 1.2.3 The foregoing grid point forecasts shall be issued by a WAFC in binary code form using the GRIB code form prescribed by the World Meteorological Organization (WMO). Note. — The GRIB code form is contained in the Manual on Codes (WMO-No. 306), Volume I.2, Part B — Binary Codes. 1.2.4 The foregoing grid point forecasts a, b, c, d) and h shall be prepared by a WAFC in a regular grid with a horizontal resolution of 1.25° of latitude and longitude. 1.2.5 The foregoing grid point forecasts e), f) and g) shall be prepared by a WAFC in a regular grid with a horizontal resolution of 0.25° of latitude and longitude. 1.3 Significant weather (SIGWX) forecasts 1.3.1 General Provisions 1.3.1.1 Forecasts of significant en-route weather phenomena shall be prepared as SIGWX forecasts four times a day by a WAFC and shall be valid for fixed valid times at 24 hours after the time (0000, 0600, 1200 and 1800 UTC) of the synoptic data on which the forecasts were based. Each forecast shall be disseminated as soon as technically feasible but not later than 7 hours after standard time of observation under normal operations and not later than 9 hours after standard time of observation during backup operations.1.3.1.2 SIGWX forecasts shall be issued in binary code form using the BUFR code form prescribed by WMO. Note. — The BUFR code form is contained in the Manual on Codes (WMO-No. 306), Volume I.2, Part B — Binary Codes. 1.3.1.3 As of 4 November 2021, in addition to 1.3.1.2, SIGWX forecasts should be disseminated in IWXXM GML form. Note 1. — Guidance on the implementation of IWXXM is provided in the Manual on the ICAO Meteorological Information Exchange Model (IWXXM) (Doc 10003). Note 2. — Geography markup language (GML) is an encoding standard of the Open Geospatial Consortium (OGC). 2. Aerodrome Meteorological Offices 2.1 Use of WAFS products 2.1.1 Aerodrome meteorological offices shall use forecasts issued by the WAFCs in the preparation of flight documentation, whenever these forecasts cover the intended flight path in respect of time, altitude and geographical extent, unless otherwise agreed between the meteorological authority and the operator concerned. 2.1.2 In order to ensure uniformity and standardization of flight documentation, the WAFS GRIB and BUFR data received and, as of 4 November 2021, IWXXM data received, shall be decoded into standard WAFS charts in accordance with relevant provisions in this CAR, and the meteorological content and identification of the originator of the WAFS forecasts shall not be amended. 2.2 Notifications of WAFC concerning significant discrepancies Aerodrome meteorological offices using WAFS BUFR or, as of 4 November 2021, IWXXM data shall notify the WAFC concerned immediately if significant discrepancies are detected or reported in respect of WAFS SIGWX forecasts concerning: a) icing, turbulence, cumulonimbus clouds that are obscured, frequent, embedded or occurring at a squall line, and sandstorms/dust storms; and b) Volcanic eruptions or a release of radioactive materials into the atmosphere, of significance to aircraft operations. The WAFC receiving the message shall acknowledge its receipt to the originator, together with brief comment on the report and any action taken, using the same means of communication employed by the originator.Note. — Guidance on reporting significant discrepancies is provided in the Manual of Aeronautical Meteorological Practice (Doc 8896). 3. Volcanic Ash Advisory Centre’s (VAAC) 3.1 Volcanic ash advisory information The technical specifications related to Volcanic Ash Advisory center’s (VAACs) are stipulated in Appendix 2 of ICAO Annex 3 for the contracting states which have accepted responsibilities for providing a VAAC. India is not a VAAC. However, the Service Provider shall have to be familiar with the technical specifications so as to be able to interact with VAAC and use its products/services effectively. 4. State Volcano Observatories 4.1 Information from State volcano observatories The ICAO stipulates in Appendix 2 of Annex 3 the technical specifications required of contracting states which maintain volcano observatories monitoring active volcanoes. India does not maintain any volcano observatories. However, the Service Provider shall have to be familiar with the roles/functions of volcano observatories in the region so as to be able to interact with them and use its products/services effectively. 5. Tropical Cyclone Advisory Centre’s (TCAC) 5.1 Tropical cyclone advisory information 5.1.1 The advisory information on tropical cyclones shall be issued for tropical cyclones when the maximum of the 10-minute mean surface wind speed is expected to reach or exceed 17 m/s (34 kt) during the period covered by the advisory. 5.1.2 The advisory information on tropical cyclones disseminated in abbreviated plain language, using approved ICAO abbreviations and numerical values of self-explanatory nature, shall be in accordance with the template shown in Table A2-2. 5.1.3 Until 4 November 2020, tropical cyclone advisory information should be disseminated in IWXXM GML form in addition to the issuance of this advisory information in accordance with 5.1.2.5.1.4 As of 5 November 2020, tropical cyclone advisory Centre’s shall disseminate tropical cyclone advisory information in IWXXM GML form in addition to the dissemination of this advisory information in abbreviated plain language in accordance with 5.1.2. Note. — The technical specifications for IWXXM are contained in the Manual on Codes (WMO-No. 306), Volume I.3, Part D — Representation Derived from Data Models. Guidance on the implementation of IWXXM is provided in the Manual on the ICAO Meteorological Information Exchange Model (IWXXM) (Doc 10003). 5.1.5 The tropical cyclone advisory information listed in Table A2-2, when prepared in graphical format, shall be as specified in Appendix 1 and issued using the PNG format. 6. Space Weather Centre The technical specifications related to SWXC are stipulated in Chapter 3, para 3.8, Appendix 2 and Attachment E of ICAO Annex 3 for the contracting states which have accepted responsibilities to monitor and provide advisory information on space weather. India is not a SWXC. However, the Service Provider shall have to be familiar with the technical specifications so as to be able to interact with SWXC and use its products/services effectively. Table A2-1. Template for advisory message for volcanic ash Key: M = inclusion mandatory, part of every message; O = inclusion optional; C = inclusion conditional, included whenever applicable; = = a double line indicates that the text following it should be placed on the subsequent line. Note 1. — The ranges and resolutions for the numerical elements included in advisory messages for volcanic ash are shown in Appendix 6, Table A6-4. Note 2. — The explanations for the abbreviations can be found in the Procedures for Air Navigation Services — ICAO Abbreviations and Codes (PANS-ABC, Doc 8400). Note 3. — Inclusion of a colon after each element heading is mandatory. Note 4.— The numbers 1 to 19 are included only for clarity and are not part of the advisory message, as shown in the examples.Element Detailed content Template(s) Examples 1 Identification of Type of message VA ADVISORY VA ADVISORY the type of message (M) 2 Status indicator Indicator of test or STATUS: TEST or EXER STATUS: TEST (C)1 exercise EXER 3 Time of origin (M) Year, month, day and DTG: nnnnnnnn/nnnnZ DTG: 20080923/0130Z time in UTC Element Detailed content Template(s) Examples 4 Name of VAAC Name of VAAC VAAC: nnnnnnnnnnnn VAAC: TOKYO (M) 5 Name of volcano Name and IAVCEI2 VOLCANO: nnnnnnnnnnnnnnnnnnnnnn [nnnnnn] VOLCANO: KARYMSKY 300130 (M) number of volcano or UNKNOWN or UNNAMED UNNAMED UNKNOWN 6 Location of Location of volcano in PSN: Nnnnn or Snnnn PSN: N5403 E15927 volcano (M) degrees and minutes Wnnnnn or Ennnnn or UNKNOWN UNKNOWN 7 State or region State, or region if ash AREA: Nnnnnnnnnnnnnnnn AREA: RUSSIA (M) is not reported over a Or State UNKNOWN UNKNOWN 8 Summit elevation Summit elevation in m SUMMIT ELEV: nnnnM (or nnnnnFT) SUMMIT ELEV: 1536M (M) (or ft) or SFC or UNKNOWN SFC 9 Advisory number Year in full and ADVISORY NR: nnnn/[n][n][n]n ADVISORY NR: 2008/4 (M) message number (separate sequence for each volcano) 10 Information Information source INFO SOURCE: Free text up to 32 characters INFO SOURCE: HIMAWARI-8 source (M) using free text KVERT KEMSD 11 Colour code (O) Aviation colour code AVIATION COLOUR RED or ORANGE or YELLOW or GREEN AVIATION RED CODE: or UNKNOWN or NOT GIVEN COLOUR or NIL CODE: 12 Eruption details Eruption details ERUPTION DETAILS: Free text up to 64 characters ERUPTION ERUPTION AT (M) (including date/time of or DETAILS: 20080923/0000Z FL300 eruption(s)) UNKNOWN REPORTED NO ERUPTION - RE- SUSPENDED VA6 UNKNOWN 13 Time of Day and time (in UTC) OBS (or EST) VA DTG: nn/nnnnZ OBS VA DTG: 23/0100Z observation (or of observation (or estimation) of ash estimation) of volcanic (M) ash Element Detailed content Template(s) Examples 15 Forecast height Day and time (in UTC) FCST VA CLD nn/nnnnZ FCST VA CLD 23/0700Z and position of the (6 hours from the “Time +6 HR: SFC or FLnnn/[FL]nnn +6 HR: FL250/350 ash clouds of observation (or [nnKM WID LINE3 BTN (nnNM WID LINE BTN)] N5130 E16030 – (+6 HR) (M) estimation) of ash” Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – N5130 E16230 – given in Item13); Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn][ – N5330 E16230 – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – N5330 E16030 Forecast height and Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – SFC/FL180 position (in degrees Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]]4 N4830 E16330 –and minutes) for each or N4830 E16630 – 14 Observed or Horizontal (in degrees OBS VA CLD or TOP FLnnn or SFC/FLnnn or FLnnn/nnn OBS VA CLD: FL250/300 cloud mass for that NO VA EXP N5130 E16630 – estimated ash and minutes) and EST VA CLD: [nnKM WID LINE3 BTN (nnNM WID LINE BTN)] N5400 E15930 – fixed valid time or N5130 E16330 cloud (M) vertical extent at the Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – N5400 E16100 – time of observation of N NO nnT [ nA nV ] B oL r Snn[nn] Wnnn[nn] or Ennn[nn][ – N5300 E15945 or NO VA EXP the observed or Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – MOV SE 20KT estimated ash cloud or, N NO nnT [ nP nR ] O orV SID nnE [D nn ] Wnnn[nn] or Ennn[nn] – SFC/FL200 NOT AVBL if the base is unknown, Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]] N5130 E16130 – the top of the observed MOV N nnKMH (or KT) or N5130 E16230 – NOT PROVIDED or estimated ash cloud; MOV NE nnKMH (or KT) or N5230 E16230 – 16 Forecast height Day and time (in UTC) FCST VA CLD nMnO/nVn nEn nZn KMH (or KT) or FCST VA CLD 2N35/213300 0EZ1 6130 and position of the (M1o2v heomuersn ftr oofm th teh e +12 HR: SMFOCV o Sr EF LnnnnKnM/[FHL (]onrn Kn T) or +12 HR: SMFOCV/F SLE2 7105 KT ash clouds “oTbismeerv oefd o obrs eersvtiamtiaotne d(o r [MnnOKVM S W nInDK LMINHE ( 3o BrT KNT ()n onrN M WID LINE BTN)] N4830 E16130 – (+12 HR) (M) eassthim calotuiodn ) of ash” NMnOnV[n SnW] o rn SnnKnM[nHn (] oWr KnnTn) [onrn ] or Ennn[nn] – NTO48P3 F0L E214606 M00O –V W given in Item13); NMnOnV[n Wn] onrn SKnMnH[n (no]r WKnTn) no[rn n] or Ennn[nn][ – N405K3M00H E 16600 – NMnOnV[n Nn]W o rn SnnKnM[nHn ]( oWr nKnTn)4[n n] or Ennn[nn] – N5300 E16130 Forecast height and Norn n[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – VA NOT IDENTIFIABLE position (in degrees NVAnn N[nOnT] oIDr SEnNnT[nIFnI]A WBLnEnn F[nMn ] or Ennn[nn]]4 NFMO SVAAT EEXLPL ITE DATA and minutes) for each oSrA TELLITE DATA WIND FL050/070 cloud mass for that NWOIN VDA F ELXnnPn /nnn N18O0T/1 A2VMBPLS fixed valid time onrn n/nn[n]MPS (or KT)5 or NWOINTD A FVLBnLn n/nnn VRBnnMPS (or KT) or NOT PROVIDED oWr IND SFC/FLnnn nnn/nn[n]MPS (or KT) or NWOINTD P SRFOCV/IFDLEnDnn VRBnnMPS (or KT) 17 Forecast height Day and time (in UTC) FCST VA CLD nn/nnnnZ FCST VA CLD 23/1900Z and position of the (18 hours from the +18 HR: SFC or FLnnn/[FL]nnn +18 HR: ash clouds “Time of observation (or [nnKM WID LINE3 BTN (nnNM WID LINE BTN)] NO VA EXP (+18 HR) (M) estimation) of ash” Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – given in Item13); Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn][ – NOT AVBL Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Forecast height and Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – NOT PROVIDED position (in degrees Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]]4 and minutes) for each or cloud mass for that NO VA EXP fixed valid time or NOT AVBL or NOT PROVIDED 18 Remarks (M) Remarks, as necessary RMK: Free text up to 256 characters RMK: LATEST REP FM KVERT or (0120Z) INDICATES NIL ERUPTION HAS CEASED. TWO DISPERSING VA CLD ARE EVIDENT ON SATELLITE IMAGERY RE-SUSPENDED VA6 NIL Element Detailed content Template(s) Examples19 Next advisory (M) Year, month, day and NXT ADVISORY: nnnnnnnn/nnnnZ NXT ADVISORY: 20080923/0730Z time in UTC or NO LATER THAN NO LATER THAN nnnnnnnn/nnnnZ nnnnnnnn/nnnnZ or NO FURTHER ADVISORIES NO FURTHER or ADVISORIES WILL BE ISSUED BY nnnnnnnn/nnnnZ WILL BE ISSUED BY nnnnnnnn/nnnnZ Notes. — 1. Used only when the message issued to indicate that a test or an exercise is taking place. When the word “TEST” or the abbreviation “EXER” is included, the message may contain information that should not be used operationally or will otherwise end immediately after the word "TEST". [Applicable 7 November 2019] 2. International Association of Volcanology and Chemistry of the Earth’s Interior (IAVCEI). 3. A straight line between two points drawn on a map in the Mercator projection or a straight line between two points which crosses lines of longitude at a constant angle. 4. Up to 4 selected layers. 5. If ash reported (e.g. AIREP) but not identifiable from satellite data. 6. To be included (as free text) only for those situations where volcanic ash has been re- suspended. To be included (as free text) where space in the remarks section allows. Example A2-1. Advisory message for volcanic ash VA ADVISORY DTG: 20080923/0130Z VAAC: TOKYO VOLCANO: KARYMSKY 300130 PSN: N5403 E15927 AREA: RUSSIA SUMMIT ELEV: 1536M ADVISORY NR: 2008/4 INFO SOURCE: HIMAWARI-8 KVERT KEMSD AVIATION COLOUR CODE: RED ERUPTION DETAILS: ERUPTION AT 20080923/0000Z FL300 REPORTED OBS VA DTG: 23/0100Z OBS VA CLD: FL250/300 N5400 E15930 – N5400 E16100 – N5300 E15945 MOV SE 20KT SFC/FL200 N5130 E16130 – N5130 E16230 – N5230 E16230 – N5230 E16130 MOV SE 15KT FCST VA CLD +6 HR: 23/0700Z FL250/350 N5130 E16030 – N5130 E16230 – N5330 E16230 – N5330 E16030 SFC/FL180 N4830 E16330 – N4830 E16630 – N5130 E16630 – N5130 E16330 FCST VA CLD +12 HR: 23/1300Z SFC/FL270 N4830 E16130 – N4830 E16600 – N5300 E16600 – N5300 E16130 FCST VA CLD +18 HR: 23/1900Z NO VA EXP RMK: LATEST REP FM KVERT (0120Z) INDICATES ERUPTION HAS CEASED. TWO DISPERSING VA CLD ARE EVIDENT ON SATELLITE IMAGERY NXT ADVISORY: 20080923/0730ZTable A2-2. Template for advisory message for tropical cyclones Key: M = inclusion mandatory, part of every message; C = inclusion conditional, included whenever applicable; O = inclusion optional; = = a double line indicates that the text following it should be placed on the subsequent line. Note 1.— The ranges and resolutions for the numerical elements included in advisory messages for tropical cyclones are shown in Appendix 6, Table A6-4. Note 2.— The explanations for the abbreviations can be found in the PANS-ABC (Doc 400). Note 3. — Inclusion of a colon after each element heading is mandatory. Note 4.— The numbers 1 to 21 are included only for clarity and are not part of the advisory message, as shown in the examples. Element Detailed content Template(s) Examples 1 Identification of the Type of message TC ADVISORY TC ADVISORY type of message (M) 2 Status indicator (C)1 Indicator of test or exercise STATUS: TEST or EXER STATUS: TEST EXER 3 Time of origin (M) Year, month, day and time DTG: nnnnnnnn/nnnnZ DTG: 20040925/1900Z in UTC of issue 4 Name of TCAC (M) Name of TCAC (location TCAC: nnnn or nnnnnnnnnn TCAC: YUFO2 indicator or full name) MIAMI 5 Name of tropical Name of tropical cyclone or TC: nnnnnnnnnnnn or NN TC: GLORIA cyclone (M) “NN” for unnamed tropical cyclone 6 Advisory number (M) Year in full and message ADVISORY NR: nnnn/[n][n][n]n ADVISORY NR: 2004/13 number (separate sequence for each cyclone) 7 Observed position Day and time in UTCand OBS PSN: nn/nnnnZ OBS PSN: 25/1800Z of the centre (M) position of the centre of the Nnn[nn] or Snn[nn] N2706 W07306 tropical cyclone (in degrees Wnnn[nn] or Ennn[nn] and minutes) 8 Observed CB cloud3 Location of CB cloud CB: WI nnnKM (or nnnNM) OF TC CENTRE CB: WI 250NM OF TC (O) (referring to latitude and or CENTRE TOP longitude (in degrees and WI4 Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – FL500 minutes)) and vertical Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – extent (flight level) Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – NIL [Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]] and TOP [ABV or BLW] FLnnn NIL9 Direction and speed Direction and speed of MOV: N nnKMH (or KT) or NNE nnKMH (or KT) or MOV: NW 20KMH of movement (M) movement given in sixteen NE nnKMH (or KT) or ENE nnKMH (or KT) or compass points and km/h E nnKMH (or KT) or ESE nnKMH (or KT) or (or kt), respectively, or SE nnKMH (or KT) or SSE nnKMH (or KT) or stationary (< 2 km/h (1 kt)) S nnKMH (or KT) or SSW nnKMH (or KT) or SW nnKMH (or KT) or WSW nnKMH (or KT) or W nnKMH (or KT) or WNW nnKMH (or KT) or NW nnKMH (or KT) or NNW nnKMH (or KT) or STNR 10 Changes in intensity Changes of maximum INTST CHANGE: INTSF or INTST CHANGE: INTSF (M) surface wind speed at time WKN or of observation NC 11 Central pressure Central pressure (in hPa) C: nnnHPA C: 965HPA (M) 12 Maximum surface Maximum surface wind MAX WIND: nn[n]MPS MAX WIND: 22MPS wind (M) near the centre (mean over (or nn[n]KT) 10 minutes, in m/s (or kt)) 13 Forecast of centre Day and time (in UTC) FCST PSN nn/nnnnZ FCST PSN +6 HR: 25/2200Z position (6 hours from the “DTG” +6 HR: Nnn[nn] or Snn[nn] N2748 W07350 (+6 HR) (M) given in Item 3); Wnnn[nn] or Ennn[nn] Forecast position (in degrees and minutes) of the centre of the tropical cyclone 14 Forecast of Forecast of maximum FCST MAX WIND nn[n]MPS FCST MAX WIND 22MPS maximum surface surface wind (6 hours after +6 HR: (or nn[n]KT) +6 HR: wind (+6 HR) (M) the “DTG” given in Item 3) 15 Forecast of centre Day and time (in UTC) FCST PSN nn/nnnnZ FCST PSN +12 HR: 26/0400Z position (12 hours from the “DTG” +12 HR: Nnn[nn] or Snn[nn] N2830 W07430 (+12 HR) (M) given in Item 3); Wnnn[nn] or Ennn[nn] Forecast position (in degrees and minutes) of the centre of the tropical cyclone 16 Forecast of Forecast of maximum FCST MAX WIND nn[n]MPS FCST MAX WIND 22MPS maximum surface surface wind (12 hours +12 HR: (or nn[n]KT) +12 HR: wind (+12 HR) (M) after the “DTG” given in Item 3) 17 Forecast of centre Day and time (in UTC) FCST PSN nn/nnnnZ FCST PSN +18 HR: 26/1000Z position (18 hours from the “DTG” +18 HR: Nnn[nn] or Snn[nn] N2852 W07500 (+18 HR) (M) given in Item 3); Wnnn[nn] or Ennn[nn] Forecast position (in degrees and minutes) of the centre of the tropical cyclone 18 Forecast of Forecast of maximum FCST MAX WIND nn[n]MPS FCST MAX WIND 21MPS maximum surface surface wind (18 hours +18 HR: (or nn[n]KT) +18 HR: wind (+18 HR) (M) after the “DTG” given in Item 3) 19 Forecast of centre Day and time (in UTC) FCST PSN nn/nnnnZ FCST PSN +24 HR: 26/1600Z position (24 hours from the “DTG” +24 HR: Nnn[nn] or Snn[nn] N2912 W07530 (+24 HR) (M) given in Item 3); Wnnn[nn] or Ennn[nn] Forecast position (in degrees and minutes) of the centre of the tropical cyclone20 Forecast of Forecast of maximum FCST MAX WIND nn[n]MPS FCST MAX WIND 20MPS maximum surface surface wind (24 hours +24 HR: (or nn[n]KT) +24 HR: wind (+24 HR) (M) after the “DTG” given in Item 3) 21 Remarks (M) Remarks, as necessary RMK: Free text up to 256 characters RMK: NIL or NIL 22 Expected time of Expected year, month, day NXT MSG: [BFR] nnnnnnnn/nnnnZ NXT MSG: 20040925/2000Z issuance of next and time (in UTC) of or advisory (M) issuance of next advisory NO MSG EXP Notes. — 1. Used only when the message issued to indicate that a test or an exercise is taking place. When the word “TEST” or the abbreviation “EXER” is included, the message may contain information that should not be used operationally or will otherwise end immediately after the word "TEST". [Applicable 7 November 2019] 2. Fictitious location. 3. In the case of CB clouds associated with a tropical cyclone covering more than one area within the area of responsibility, this element can be repeated, as necessary. The number of coordinates should be kept to a minimum and should not normally exceed seven. Example A2-2. Advisory message for tropical cyclones TC ADVISORY DTG: 20040925/1900Z TCAC: YUFO* TC: GLORIA ADVISORY NR: 2004/13 OBS PSN: 25/1800Z N2706 W07306 CB: WI 250NM OF TC CENTRE TOP FL500 MOV: NW 20KMH INTST CHANGE INTSF C: 965HPA MAX WIND: 25MPS FCST PSN +6 HR: 25/2200Z N2748 W07350 FCST MAX WIND +6 HR: 22MPS FCST PSN +12 HR: 26/0400Z N2830 W07430 FCST MAX WIND +12 HR: 22MPS FCST PSN +18 HR: 26/1000Z N2852 W07500 FCST MAX WIND +18 HR: 21MPS FCST PSN +24 HR: 26/1600Z N2912 W07530 FCST MAX WIND +24 HR: 20MPS RMK: NIL NXT MSG: 20040925/2000Z *Ficticious locationTable A2-3. Template for advisory message for space weather information Key: M = inclusion mandatory, part of every message; C = inclusion conditional, included whenever applicable; = = a double line indicates that the text following it should be placed on the subsequent line. Note 1.— The explanations for the abbreviations can be found in the PANS-ABC (Doc 8400). Note 2. — The spatial resolutions are shown in Attachment E. Note 3. — Inclusion of a colon after each element heading is mandatory. Note 4.— The numbers 1 to 14 are included only for clarity and are not part of the advisory message, as shown in the examples. Element Detailed content Template(s) Examples 1 Identification of the Type of message SWX ADVISORY SWX ADVISORY type of message (M) 2 Status indicator Indicator of test or STATUS: TEST or EXER STATUS: TEST (C)1 exercise EXER 3 Time of origin (M) Year, month, day and DTG: nnnnnnnn/nnnnZ DTG: 20161108/0100Z time in UTC 4 Name of SWXC (M) Name of SWXC SWXC: Nnnnnnnnnnnn SWXC: DONLON2 5 Advisory number Year in full and unique ADVISORY NR: nnnn/[n][n][n]n ADVISORY NR: 2016/1 (M) message number 6 Number of advisory Number of the previously NR RPLC: nnnn/[n][n][n]n NR RPLC: 2016/1 being replaced (C) issued advisory being replaced 7 Space weather Effect and intensity of SWX EFFECT: HF COM MOD or SEV [AND]3 or SWX EFFECT: HF COM MOD effect and intensity the space weather SATCOM MOD or SEV [AND]3 or (M) phenomena GNSS MOD or SEV [AND]3 or SATCOM SEV RADIATION4 MOD or SEV GNSS SEV HF COM MOD AND SATCOM MOD AND GNSS MOD RADIATION MOD SATCOM SEV 8 Observed or Day and time (n UTC) of OBS nn/nnnnZ OBS SWX:: 08/0100Z DAYLIGHT expected space observed phenomena (or FCST) SWX: DAYLIGHT SIDE or SIDE weather (or forecast if HNH and/or MNH and/or EQN and/or phenomena (M) phenomena have yet to EQS and/or MSH and/or HSH Wnnn(nn) or 08/0100Z HNH HSH occur); Ennn(nn) – Wnnn(nn) or Ennn(nn) E18000 – W18000 and/or Horizontal extent3 ABV FLnnn or FLnnn – nnn and/or 08/0100Z HNH HSH (latitude bands and Nnn[nn] or Snn[nn] Wnnn[nn] orEnnn[nn] – W18000 – W09000 ABV longitude in degrees) Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – FL350 and/or altitude of space Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – weather phenomena [Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – 08/0100Z S2000 Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]] W17000 – S2000 or W13000 – S1000Element Detailed content Template(s) Examples NO SWX EXP W13000 – S1000 W17000 – S2000 W17000 NO SWX EXP 9 Forecast of the Day and time (in UTC) FCST SWX +6 HR: nn/nnnnZ FCST SWX +6 HR: 08/0700Z DAYLIGHT phenomena (+6 (6 hours from the time DAYLIGHT SIDE or SIDE HR) (M) given in Item 8, rounded HNH and/or MNH and/or EQN and/or to the next full hour); EQS and/or MSH and/or HSH 08/0700Z HNH HSH Wnnn(nn) or Ennn(nn) – Wnnn(nn) or Ennn(nn) W18000 – W09000 ABV Forecast extent and/or and/or FL350 altitude of the space ABV FLnnn or FLnnn – nnn and/or weather phenomena for Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – 08/0700Z HNH HSH that fixed valid time Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – E18000 – W18000 Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – [Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – NO SWX EXP Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]] or NOT AVBL NO SWX EXP or NOT AVBL 10 Forecast of the Day and time (in UTC) FCST SWX +12 HR: nn/nnnnZ FCST SWX +12 HR: 08/1300Z DAYLIGHT phenomena (+12 (12 hours from the time DAYLIGHT SIDE or SIDE HR) (M) given in Item 8, rounded HNH and/or MNH and/or EQN and/or to the next full hour). EQS and/or MSH and/or HSH 08/1300Z HNH HSH Wnnn(nn) or Ennn(nn) – Wnnn(nn) or Ennn(nn) W18000 – W09000 ABV Forecast extent and/or and/or FL350 altitude of the space ABV FLnnn or FLnnn – nnn and/or weather phenomena for Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – 08/1300Z HNH HSH that fixed valid time Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – E18000 – W18000 Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – [Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – NO SWIX EXP Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]] or NOT AVBL NO SWX EXP or NOT AVBL 11 Forecast of the Day and time (in UTC) FCST SWX +18 HR: nn/nnnnZ FCST SWX +18 HR: 08/1900Z DAYLIGHT phenomena (+18 (18 hours from the time DAYLIGHT SIDE or SIDE HR) (M) given in Item 8, rounded HNH and/or MNH and/or EQN and/or to the next full hour). EQS and/or MSH and/or HSH 08/1900Z HNH HSH Wnnn(nn) or Ennn(nn) – Wnnn(nn) or Ennn(nn) W18000 – W09000 ABV Forecast extent and/or and/or FL350 altitude of the space ABV FLnnn or FLnnn – nnn and/or weather phenomena for Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – 08/1900Z HNH HSH that fixed valid time Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – E18000 – W18000 Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – [Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – NO SWX EXP Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]] or NOT AVBL NO SWX EXP or NOT AVBL 12 Forecast of the Day and time (in UTC) FCST SWX +24 HR: nn/nnnnZ FCST SWX +24 HR: 09/0100Z DAYLIGHT phenomena (+24 (24 hours from the time DAYLIGHT SIDE or SIDE HR) (M) given in Item 8, rounded HNH and/or MNH and/or EQN and/or to the next full hour). EQS and/or MSH and/or HSH 09/0100Z HNH HSH Wnnn(nn) or Ennn(nn) – Wnnn(nn) or Ennn(nn) W18000 – W09000 ABV Forecast extent and/or and/or FL350 altitude of the space ABV FLnnn or FLnnn – nnn and/or weather phenomena for Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – 09/0100Z HNH HSH that fixed valid time Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – E18000 – W18000 Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – [Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – NO SWX EXP Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]]Element Detailed content Template(s) Examples or NOT AVBL NO SWX EXP or NOT AVBL 13 Remarks (M) Remarks, as necessary RMK: Free text up to 256 characters RMK: SWX EVENT HAS or CEASED NIL WWW.SPACEWEATHER PROVIDER.GOV NIL 14 Next advisory (M) Year, month, day and NXT ADVISORY: nnnnnnnn/nnnnZ NXT ADVISORY: 20161108/0700Z time in UTC or NO FURTHER ADVISORIES NO FURTHER or ADVISORIES WILL BE ISSUED BY nnnnnnnn/nnnnZ WILL BE ISSUED 20210726/1800Z BY Notes. — 1. Used only when the message issued to indicate that a test or an exercise is taking place. When the word “TEST” or the abbreviation “EXER” is included, the message may contain information that should not be used operationally or will otherwise end immediately after the word "TEST". [Applicable 7 November 2019] 2. Fictitious location. 3. One or more effects with the same intensity may be combined. 4. One or more latitude ranges may be included in the space weather advisory information. Example A2-3. Space weather advisory message (GNSS and HFCOM effects) SWX ADVISORY DTG: 20161108/0100Z SWXC: DONLON* ADVISORY NR: 2016/2 NR RPLC: 2016/1 SWX EFFECT: HF COM MOD AND GNSS MOD OBS SWX: 08/0100Z HNH HSH E18000 – W18000 FCST SWX +6 HR: 08/0700Z HNH HSH E18000 – W18000 FCST SWX +12 HR: 08/1300Z HNH HSH E18000 – W18000 FCST SWX +18 HR: 08/1900Z HNH HSH E18000 – W18000 FCST SWX +24 HR 09/0100Z NO SWX EXP RMK: LOW LVL GEOMAGNETIC STORMING CAUSING INCREASED AURORAL ACT AND SUBSEQUENT MOD DEGRADATION OF GNSS AND HF COM AVBL IN THE AURORAL ZONE. THIS STORMING EXP TO SUBSIDE IN THE FCST PERIOD. SEE WWW.SPACEWEATHERPROVIDER.WEB NXT ADVISORY: NO FURTHER ADVISORIES * Fictitious LocationExample A2-4. Space weather advisory message (RADIATION effects) SWX ADVISORY DTG: 20161108/0000Z SWXC: DONLON* ADVISORY NR: 2016/2 NR RPLC: 2016/1 SWX EFFECT: RADIATION MOD FCST SWX: 08/0100Z HNH HSH E18000 – W18000 ABV FL 350 FCST SWX +6 HR: 08/0700Z HNH HSH E18000 – W18000 ABV FL 350 FCST SWX +12 HR: 08/1300Z HNH HSH E18000 – W18000 ABV FL 350 FCST SWX +18 HR: 08/1900Z HNH HSH E18000 – W18000 ABV FL 350 FCST SWX +24 HR: 09/0100Z NO SWX EXP RMK: RADIATION LVL EXCEEDED 100 PCT OF BACKGROUND LVL AT FL350 AND ABV. THE CURRENT EVENT HAS PEAKED AND LVL SLW RTN TO BACKGROUND LVL. SEE WWW.SPACEWEATHERPROVIDER.WEB NXT ADVISORY: NO FURTHER ADVISORIES * Fictitious Location Example A2-5. Space weather advisory message (GNSS and HFCOM effects) SWX ADVISORYDTG: 20161108/0100Z SWXC: DONLON* ADVISORY NR: 2016/1 SWX EFFECT: HF COM SEV OBS SWX: 08/0100Z DAYLIGHT SIDE FCST SWX +6 HR: 08/0700Z DAYLIGHT SIDE FCST SWX +12 HR: 08/1300Z DAYLIGHT SIDE FCST SWX +18 HR: 08/1900Z DAYLIGHT SIDE FCST SWX +24 HR 09/0100Z NO SWX EXP RMK: PERIODIC HF COM ABSORPTION AND LIKELY TO CONT IN THE NEAR TERM. CMPL AND PERIODIC LOSS OF HF ON THE SUNLIT SIDE OF THE EARTH EXP. CONT HF COM DEGRADATION LIKELY OVER THE NXT 7 DAYS. SEE WWW.SPACEWEATHERPROVIDER.WEB NXT ADVISORY: 20161108/0700Z * Ficticious location APPENDIX 3. TECHNICAL SPECIFICATIONS RELATED TO METEOROLOGICAL OBSERVATIONS AND REPORTS (See Para 4 of this CAR) 1. General provision related to meteorological observations 1.1 Meteorological Observation 1.1.1 The meteorological instruments used at an aerodrome should be situated in such a way as to supply data which are representative of the area for which the measurements are required. Note. — Specifications concerning the siting of equipment and installations on operational areas, aimed at reducing the hazard to aircraft to a minimum, are contained in Annex 14, Volume I, Para 9. 1.1.2 Meteorological instruments at aeronautical meteorological stations should be exposed, operated and maintained in accordance with the practices, procedures and specifications promulgated by the World Meteorological Organization (WMO). 1.1.3 The observers at an aerodrome should be located, in so far as is practicable, so as to supply data which are representative of the area for which the observations are required. 1.1.4 Where automated equipment forms part of an integrated semi- automatic observing system, displays of data which are made available to the local ATS units should be a subset of and displayed parallel to those available in the local meteorological service unit. In those displays, each meteorological element should be annotated to identify, as appropriate, the locations for which the element is representative. 2. General criteria related to meteorological reports2.1 Format of meteorological reports 2.1.1 Local routine and special reports shall be issued in abbreviated plain language, in accordance with the template shown in Table A3-1. 2.1.2 METAR and SPECI shall be issued in accordance with the template shown in Table A3- 2 and disseminated in the METAR and SPECI code forms prescribed by the WMO. Note. — The METAR and SPECI code forms are contained in WMO Publication No. 306, Manual on Codes, Volume I.1, Part A — Alphanumeric Codes. 2.1.3 Until 4 November 2020, METAR and SPECI should be disseminated in IWXXM GML form in addition to the dissemination of the METAR and SPECI in accordance with 2.1.2. 2.1.4 As of 5 November 2020, METAR AND SPECI shall be disseminate in IWXXM GML form in addition to the dissemination of the METAR AND SPECI in accordance with 2.1.2. Note. — The technical specifications for IWXXM are contained in the Manual on Codes (WMO-No. 306), Volume I.3, Part D — Representation Derived from Data Models. Guidance on the implementation of IWXXM is provided in the Manual on the ICAO Meteorological Information Exchange Model (IWXXM) (Doc 10003). 2.2 Use of CAVOK When the following conditions occur simultaneously at the time of observation: a) visibility, 10 km or more, and the lowest visibility is not reported; Note 1.— In local routine and special reports, visibility refers to the value(s) to be reported in accordance with Appendix 3, Para 4.2.4.2 and 4.2.4.3; in METAR and SPECI, visibility refers to the value(s) to be reported in accordance with Appendix 3, Para 4.2.4.4. Note 2. – The lowest visibility is reported in accordance with Appendix 3, Para 4.2.4.4 a). b) no cloud of operational significance; c) no weather of significance to aviation as given in Appendix 3, Para 4.4.2.3, 4.4.2.5 and 4.4.2.6; Information on visibility, runway visual range, present weather and cloud amount, cloud type and height of cloud base shall be replaced in all meteorological reports by the term “CAVOK”. 2.3 Criteria for issuance of local special reports and SPECI2.3.1 The list of criteria for the issuance of local special reports shall include the following: a) those values which most closely correspond with the operating minima of the operators using the aerodrome; b) those values which satisfy other local requirements of the air traffic services units and of the operators; c) an increase in air temperature of 2°C or more from that given in the latest report, or an alternative threshold value as agreed between the meteorological authority, the appropriate ATS authority and the operators concerned; d) the available supplementary information concerning the occurrence of significant meteorological conditions in the approach and climb-out areas as given in Table A3- 1; e) when noise abatement procedures are applied in accordance with the PANS-ATM (Doc 4444) and the variation from the mean surface wind speed (gusts) has changed by 2.5 m/s (5 kt) or more from that at the time of the latest report, the mean speed before and/or after the change being 7.5 m/s (15 kt) or more; and f) Those values which constitute criteria for SPECI. 2.3.2 Where required in accordance with Para 4, 4.4.2 b), SPECI shall be issued whenever changes in accordance with the following criteria occur: a) when the mean surface wind direction has changed by 60° or more from that given in the latest report, the mean speed before and/or after the change being 5 m/s (10 kt) or more; b) when the mean surface wind speed has changed by 5 m/s (10 kt) or more from that given in the latest report; c) when the variation from the mean surface wind speed (gusts) has increased by 5 m/s (10 kt) or more from that at the time of the latest report, the mean speed before and/or after the change being 7.5 m/s (15 kt) or more; d) when the onset, cessation or change in intensity of any of the following weather phenomena occurs: — freezing precipitation — moderate or heavy precipitation (including showers thereof) — thunderstorm (with precipitation) e) when the onset or cessation of any of the following weather phenomena occurs: — freezing fog — thunderstorm (without precipitation)f) when the amount of a cloud layer below 450 m (1 500 ft) changes: 1) from SCT or less to BKN or OVC; or 2) from BKN or OVC to SCT or less; 2.3.3 Where required in accordance with Para 4, Sub Para 4.4.2 b), SPECI should be issued whenever changes in accordance with the following criteria occur: a) when the wind changes through values of operational significance. The threshold values should be established by the meteorological authority in consultation with the appropriate ATS authority and operators concerned, taking into account changes in the wind which would: 1) require a change in runway(s) in use; and 2) indicate that the runway tailwind and crosswind components have changed through values representing the main operating limits for typical aircraft operating at the aerodrome; b) when the visibility is improving and changes to or passes through one or more of the following values, or when the visibility is deteriorating and passes through one or more of the following values: 1) 800, 1500 or 3000 m; and 2) 5000 m, in cases where significant numbers of flights are operated in accordance with the visual flight rules; Note 1. — In local special reports, visibility refers to the value(s) to be reported in accordance with Appendix 3, 4.2.4.2 and 4.2.4.3; in SPECI, visibility refers to the value(s) to be reported in accordance with Appendix 3,4.2.4.4. Note 2. — Visibility refers to “prevailing visibility” except in the case where only the lowest visibility is reported in accordance with Appendix 3, 4.2.4.4 b). c) when the runway visual range is improving and changes to or passes through one or more of the following values, or when the runway visual range is deteriorating and passes through one or more of the following values: 50, 175, 300, 550 or 800 m; d) when the onset, cessation or change in intensity of any of the following weather phenomena occurs: — dust storm — sandstorm — funnel cloud (tornado or waterspout); e) when the onset or cessation of any of the following weather phenomena occurs:— low drifting dust, sand or snow — blowing dust, sand or snow — squall; f) when the height of base of the lowest cloud layer of BKN or OVC extent is lifting and changes to or passes through one or more of the following values, or when the height of base of the lowest cloud layer of BKN or OVC extent is lowering and passes through one or more of the following values: 1) 30, 60, 150 or 300 m (100, 200, 500 or 1 000 ft); and 2) 450 m (1500 ft) in cases where significant numbers of flights are operated in accordance with the visual flight rules; g) when the sky is obscured and the vertical visibility is improving and changes to or passes through one or more of the following values, or when the vertical visibility is deteriorating and passes through one or more of the following values: 30, 60, 150 or 300 m (100, 200, 500 or 1000 ft); and h) any other criteria based on local aerodrome operating minima, as agreed between the meteorological authority and the operators concerned. Note. — Other criteria based on local aerodrome operating minima are to be considered in parallel with similar criteria for the inclusion of change groups and for the amendment of TAF developed in response to Appendix 5, 1.3.2 j). 2.3.4 When a deterioration of one weather element is accompanied by an improvement in another element, a single SPECI shall be issued; it shall then be treated as a deterioration report. 3. Dissemination of meteorological reports 3.1 METAR and SPECI 3.1.1 METAR and SPECI shall be disseminated to international OPMET databanks and the Centre’s designated by regional air navigation agreement for the operation of aeronautical fixed service Internet-based services, in accordance with regional air navigation agreement. 3.1.2 METAR and SPECI shall be disseminated to other aerodromes in accordance with regional air navigation agreement. 3.1.3 SPECI representing a deterioration in conditions shall be disseminated immediately after the observation. A SPECI representing a deterioration of one weather element and an improvement in another element shall be disseminated immediately after the observation.3.1.4 A SPECI representing an improvement in conditions should be disseminated only after the improvement has been maintained for 10 minutes; it should be amended before dissemination, if necessary, to indicate the conditions prevailing at the end of that 10- minute period. 3.2 Local routine and special reports 3.2.1 Local routine reports shall be transmitted to local air traffic services units and shall be made available to the operators and to other users at the aerodrome. 3.2.2 Local special reports shall be transmitted to local air traffic services units as soon as the specified conditions occur. However, as agreement between the meteorological authority and the appropriate ATS authority, they need not be issued in respect of: a) any element for which there is in the local air traffic services unit a display corresponding to the one in the meteorological station, and where arrangements are in force for the use of this display to update information included in local routine and special reports; and b) Runway visual range, when all changes of one or more steps on the reporting scale in use are being reported to the local air traffic services unit by an observer on the aerodrome. Local special reports shall also be made available to the operators and to other users at the aerodrome. 4. Observing and reporting of meteorological elements Introductory Note. — Selected criteria applicable to meteorological information referred to under 4.1 to 4.8 for inclusion in aerodrome reports are given in tabular form at Attachment C. 4.1 Surface wind 4.1.1 Siting 4.1.1.1 Surface wind should be observed at a height of 10 ± 1 m (30 ± 3 ft) above the ground. 4.1.1.2 Representative surface wind observations should be obtained by the use of sensors appropriately sited. Sensors for surface wind observations for local routine and special reports should be sited to give the best practicable indication of conditions along the runway and touchdown zones. At aerodromes where topography or prevalent weather conditions cause significant differences in surface wind at various sections of the runway,additional sensors should be provided. Note. — Since, in practice, the surface wind cannot be measured directly on the runway, surface wind observations for take-off and landing are expected to be the best practicable indication of the winds which an aircraft will encounter during take-off and landing. 4.1.2 Displays 4.1.2.1 Surface wind displays relating to each sensor shall be located in the meteorological station with corresponding displays in the appropriate air traffic services units. The displays in the meteorological station and in the air traffic services units shall relate to the same sensors, and where separate sensors are required as specified in 4.1.1.2, the displays shall be clearly marked to identify the runway and section of runway monitored by each sensor. 4.1.2.2 The mean values of, and significant variations in, the surface wind direction and speed for each sensor should be derived and displayed by automated equipment. 4.1.3 Averaging 4.1.3.1 The averaging period for surface wind observations shall be: a) 2 minutes for local routine and special reports and for wind displays in air traffic services units; and b) 10 minutes for METAR and SPECI, except that when the 10-minute period includes a marked discontinuity in the wind direction and/or speed, only data occurring after the discontinuity shall be used for obtaining mean values; hence, the time interval in these circumstances shall be correspondingly reduced. Note. — A marked discontinuity occurs when there is an abrupt and sustained change in wind direction of 30° or more, with a wind speed of 5 m/s (10 kt) before or after the change, or a change in wind speed of 5 m/s (10 kt) or more, lasting at least 2 minutes. 4.1.3.2 The averaging period for measuring variations from the mean wind speed (gusts) reported in accordance with 4.1.5.2 c) should be 3 seconds for local routine and special reports and for METAR and SPECI and for wind displays used for depicting variations from the mean wind speed (gusts) in air traffic services units. 4.1.4 Accuracy of measurement The reported direction and speed of the mean surface wind, as well as variations from the mean surface wind, should meet the operationally desirable accuracy of measurement as given in Attachment A. 4.1.5 Reporting 4.1.5.1 In local routine and special reports and in METAR and SPECI, the surface wind directionand speed shall be reported in steps of 10 degrees true and 1 metre per second (or 1 knot), respectively. Any observed value that does not fit the reporting scale in use shall be rounded to the nearest step in the scale. 4.1.5.2 In local routine and special reports and in METAR and SPECI: a) the units of measurement used for the wind speed shall be indicated; b) variations from the mean wind direction during the past 10 minutes shall be reported as follows, if the total variation is 60° or more: 1) when the total variation is 60° or more and less than 180° and the wind speed is 1.5 m/s (3 kt) or more, such directional variations shall be reported as the two extreme directions between which the surface wind has varied; 2) when the total variation is 60° or more and less than 180° and the wind speed is less than 1.5 m/s (3 kt), the wind direction shall be reported as variable with no mean wind direction; or 3) when the total variation is 180° or more, the wind direction shall be reported as variable with no mean wind direction; c) variations from the mean wind speed (gusts) during the past 10 minutes shall be reported when the maximum wind speed exceeds the mean speed by: 1) 2.5 m/s (5 kt) or more in local routine and special reports when noise abatement procedures are applied in accordance with the PANS-ATM (Doc 4444); or 2) 5 m/s (10 kt) or more otherwise; d) when a wind speed of less than 0.5 m/s (1 kt) is reported, it shall be indicated as calm; e) when a wind speed of 50 m/s (100 kt) or more is reported, it shall be indicated to be more than 49 m/s (99 kt); and f) When the 10-minute period includes a marked discontinuity in the wind direction and/or speed, only variations from the mean wind direction and mean wind speed occurring since the discontinuity shall be reported. Note. — See note under 4.1.3.1. 4.1.5.3 In local routine and special reports: a) if the surface wind is observed from more than one location along the runway, the locations for which these values are representative shall be indicated; b) when there is more than one runway in use and the surface wind related to these runways is observed, the available wind values for each runway shall be given, andthe runways to which the values refer shall be reported; c) when variations from the mean wind direction are reported in accordance with 4.1.5.2 b) 2), the two extreme directions between which the surface wind has varied shall be reported; and d) When variations from the mean wind speed (gusts) are reported in accordance with 4.1.5.2 c), they shall be reported as the maximum and minimum values of the wind speed attained. 4.1.5.4 In METAR and SPECI, when variations from the mean wind speed (gusts) are reported in accordance with 4.1.5.2 c), the maximum value of the wind speed attained shall be reported. 4.2 Visibility 4.2.1 Siting 4.2.1.1 When instrumented systems are used for the measurement of visibility, the visibility should be measured at a height of approximately 2.5 m (7.5 ft) above the runway. 4.2.1.2 When instrumented systems are used for the measurement of visibility, representative visibility observations should be obtained by the use of sensors appropriately sited. Sensors for visibility observations for local routine and special reports should be sited to give the best practicable indications of visibility along the runway and touchdown zone. 4.2.2 Displays When instrumented systems are used for the measurement of visibility, visibility displays relating to each sensor should be located in the meteorological station with corresponding displays in the appropriate air traffic services units. The displays in the meteorological station and in the air traffic services units should relate to the same sensors, and where separate sensors are required as specified in 4.2.1, the displays should be clearly marked to identify the area, e.g. runway and section of runway, monitored by each sensor. 4.2.3 Averaging When instrumented systems are used for the measurement of visibility, their output should be updated at least every 60 seconds to permit provision of current representative values. The averaging period should be: a) 1 minute for local routine and special reports and for visibility displays in air traffic services units; and b) 10 minutes for METAR and SPECI, except that when the 10-minute periodimmediately preceding the observation includes a marked discontinuity in the visibility, only those values occurring after the discontinuity should be used for obtaining mean values. Note. — A marked discontinuity occurs when there is an abrupt and sustained change in visibility, lasting at least 2 minutes, which reaches or passes through criteria for the issuance of SPECI reports given in 2.3. 4.2.4 Reporting 4.2.4.1 In local routine and special reports and in METAR and SPECI, the visibility shall be reported in steps of 50 m when the visibility is less than 800 m; in steps of 100 m, when it is 800 m or more but less than 5 km; in kilometer steps, when the visibility is 5 km or more but less than 10 km; and it shall be given as 10 km when the visibility is 10 km or more, except when the conditions for the use of CAVOK apply. Any observed value which does not fit the reporting scale in use shall be rounded down to the nearest lower step in the scale. Note. — Specifications concerning the use of CAVOK are given in 2.2. 4.2.4.2 In local routine and special reports, visibility along the runway(s) shall be reported together with the units of measurement used to indicate visibility. 4.2.4.3 In local routine and special reports, when instrumented systems are used for the measurement of visibility: a) if the visibility is observed from more than one location along the runway as specified in Para 4, 4.6.2.2, the values representative of the touchdown zone should be reported first, followed, as necessary, by the values representative of the mid-point and stop- end of the runway, and the locations for which these values are representative should be indicated; and b) When there is more than one runway in use and the visibility is observed related to these runways, the available visibility values for each runway should be reported, and the runways to which the values refer should be indicated. 4.2.4.4 In METAR and SPECI, visibility should be reported as prevailing visibility, as defined in Para 1. When the visibility is not the same in different directions and a) when the lowest visibility is different from the prevailing visibility, and 1) less than 1500 m or 2) less than 50 per cent of the prevailing visibility and less than 5000 m; the lowest visibility observed should also be reported and, when possible, its general direction in relation to the aerodrome reference point indicated by reference to one of the eight points of the compass. If the lowest visibility is observed in more than onedirection, then the most operationally significant direction should be reported; and b) when the visibility is fluctuating rapidly, and the prevailing visibility cannot be determined, only the lowest visibility should be reported, with no indication of direction. 4.3 Runway visual range 4.3.1 Siting 4.3.1.1 Runway visual range should be assessed at a height of approximately 2.5 m (7.5 ft) above the runway for instrumented systems or assessed at a height of approximately 5 m (15 ft) above the runway by a human observer. 4.3.1.2 Runway visual range should be assessed at a lateral distance from the runway Centre line of not more than 120 m. The site for observations to be representative of the touchdown zone should be located about 300 m along the runway from the threshold. The sites for observations to be representative of the mid-point and stop-end of the runway should be located at a distance of 1000 to 1500 m along the runway from the threshold and at a distance of about 300 m from the other end of the runway. The exact position of these sites and, if necessary, additional sites should be decided after considering aeronautical, meteorological and climatological factors such as long runways, swamps and other fog- prone areas. 4.3.2 Instrument systems Note. — Since accuracy can vary from one instrument design to another, performance characteristics are to be checked before selecting an instrument for assessing runway visual range. The calibration of a forward-scatter meter has to be traceable and verifiable to a Transmissometer standard, the accuracy of which has been verified over the intended operational range. Guidance on the use of Transmissometer and forward-scatter meters in instrumented runway visual range systems is given in the Manual of Runway Visual Range Observing and Reporting Practices (Doc 9328). 4.3.2.1 Instrumented systems based on Transmissometer or forward-scatter meters shall be used to assess runway visual range on runways intended for Category II and III instrument approach and landing operations. 4.3.2.2 Instrumented systems based on Transmissometer or forward-scatter meters should be used to assess runway visual range on runways intended for Category I instrument approach and landing operations. 4.3.3 Display 4.3.3.1 Where runway visual range is determined by instrumented systems, one display or more,if required, shall be located in the meteorological station with corresponding displays in the appropriate air traffic services units. The displays in the meteorological station and in the air traffic services units shall be related to the same sensors, and where separate sensors are required as specified in 4.3.1.2, the displays shall be clearly marked to identify the runway and section of runway monitored by each sensor. 4.3.3.2 Where runway visual range is determined by human observers, runway visual range should be reported to the appropriate local air traffic services units, whenever there is a change in the value to be reported in accordance with the reporting scale (except where the provisions of 3.2.2 a) or b) apply). The transmission of such reports should normally be completed within 15 seconds after the termination of the observation. 4.3.4 Averaging Where instrumented systems are used for the assessment of runway visual range, their output shall be updated at least every 60 seconds to permit the provision of current, representative values. The averaging period for runway visual range values shall be: a) 1 minute for local routine and special reports and for runway visual range displays in air traffic services units; and b) 10 minutes for METAR and SPECI, except that when the 10-minute period immediately preceding the observation includes a marked discontinuity in runway visual range values, only those values occurring after the discontinuity shall be used for obtaining mean values. Note. — A marked discontinuity occurs when there is an abrupt and sustained change in runway visual range, lasting at least 2 minutes, which reaches or passes through the values 800, 550, 300 and 175m. 4.3.5 Runway light intensity When instrumented systems are used for the assessment of runway visual range, computations should be made separately for each available runway. For local routine and special reports, the light intensity to be used for the computation should be: a) for a runway with the lights switched on and the light intensity of more than 3 per cent of the maximum light intensity available, the light intensity actually in use on that runway; b) for a runway with the lights switched on and the light intensity of 3 per cent or less of the maximum light intensity available, the optimum light intensity that would be appropriate for operational use in the prevailing conditions; and c) for a runway with lights switched off (or at the lowest setting pending the resumption of operations), the optimum light intensity that would be appropriate for operationaluse in the prevailing conditions. In METAR and SPECI, the runway visual range should be based on the maximum light intensity available on the runway. Note. — Guidance on the conversion of instrumented readings into runway visual range is given at Attachment D. 4.3.6 Reporting 4.3.6.1 In local routine and special reports and in METAR and SPECI, the runway visual range shall be reported in steps of 25 m when the runway visual range is less than 400 m; in steps of 50 m when it is between 400 m and 800 m; and in steps of 100 m when the runway visual range is more than 800 m. Any observed value which does not fit the reporting scale in use shall be rounded down to the nearest lower step in the scale. 4.3.6.2 Fifty meters should be considered the lower limit and 2000 meters the upper limit for runway visual range. Outside of these limits, local routine and special reports and METAR and SPECI should merely indicate that the runway visual range is less than 50 m or more than 2000 m. 4.3.6.3 In local routine reports, local special reports, METAR and SPECI: a) when runway visual range is above the maximum value that can be determined by the system in use, it shall be reported using the abbreviation “ABV” in local routine and special reports and the abbreviation “P” in METAR and SPECI, followed by the maximum value that can be determined by the system; and b) When the runway visual range is below the minimum value that can be determined by the system in use, it shall be reported using the abbreviation “BLW” in local routine and special reports and the abbreviation “M” in METAR and SPECI, followed by the minimum value that can be determined by the system. 4.3.6.4 In local routine and special reports: a) the units of measurement used shall be included; b) if runway visual range is observed from only one location along the runway, i.e. the touchdown zone, it shall be included without any indication of location; c) if the runway visual range is observed from more than one location along the runway, the value representative of the touchdown zone shall be reported first, followed by the values representative of the mid-point and stop-end and the locations for which these values are representative shall be indicated; and d) when there is more than one runway in use, the available runway visual range values for each runway shall be reported and the runways to which the values refer shall be indicated.4.3.6.5 In METAR and SPECI: a) only the value representative of the touchdown zone should be reported and no indication of location on the runway should be included; and b) Where there is more than one runway available for landing, touchdown zone runway visual range values should be included for all such runways, up to a maximum of four, and the runways to which the values refer should be indicated. 4.3.6.6 In METAR and SPECI when instrumented systems are used for the assessment of runway visual range, the variations in runway visual range during the 10- minute period immediately preceding the observation should be included if the runway visual range values during the 10-minute period have shown a distinct tendency, such that the mean during the first 5 minutes varies by 100 m or more from the mean during the second 5 minutes of the period. When the variation of the runway visual range values shows an upward or downward tendency, this should be indicated by the abbreviation “U” or “D”, respectively. In circumstances when actual fluctuations during the 10-minute period show no distinct tendency, this should be indicated using the abbreviation “N”. When indications of tendency are not available, no abbreviations should be included. 4.4 Present weather 4.4.1 Siting When instrumented systems are used for observing present weather phenomena listed under 4.4.2.3 and 4.4.2.4, representative information should be obtained by the use of sensors appropriately sited. 4.4.2 Reporting 4.4.2.1 In local routine and special reports, observed present weather phenomena shall be reported in terms of type and characteristics and qualified with respect to intensity, as appropriate. 4.4.2.2 In METAR and SPECI, observed present weather phenomena shall be reported in terms of type and characteristics and qualified with respect to intensity or proximity to the aerodrome, as appropriate. 4.4.2.3 In local routine and special reports and in METAR and SPECI, the following types of present weather phenomena should be reported, using their respective abbreviations and relevant criteria, as appropriate: a) Precipitation Drizzle DZ Rain RASnow SN Snow grains SG Ice pellets PL Hail GR — Reported when diameter of largest hailstones is 5 mm or more. Small hail and/or snow pellets GS — Reported when diameter of largest hailstones is less than 5 mm. b) Obscurations (hydrometeors) Fog FG — Reported when visibility is less than 1 000 m, except when qualified by “MI”, “BC”, “PR” or “VC” (see 4.4.2.6 and 4.4.2.8). Mist BR — Reported when visibility is at least 1 000 m but not more than 5000 m. c) Obscurations (lithometeors) — The following should be used only when the obscuration consists predominantly of lithometeors and the visibility is 5 000 m or less except “SA” when qualified by “DR” (see 4.4.2.6) and volcanic ash. Sand SA Dust (widespread) DU Haze HZ Smoke FU Volcanic ash VA d) Other phenomena Dust/sand whirls (dust devils) PO Squall SQ Funnel cloud (tornado or waterspout) FC Dust storm DS Sandstrom SS 4.4.2.4 In automated local routine reports, local special reports, METAR and SPECI, in addition to the precipitation types listed under 4.4.2.3 a), the abbreviation UP should be used for unidentified precipitation when the type of precipitation cannot be identified by the automatic observing system. 4.4.2.5 In local routine and special reports and in METAR and SPECI, the following characteristics of present weather phenomena, as necessary, shall be reported, using theirrespective abbreviations and relevant criteria, as appropriate: Thunderstorm TS — Used to report a thunderstorm with precipitation in accordance with the templates shown in Tables A3-1 and A3-2. When thunder is heard or lightning is detected at the aerodrome during the 10-minute period preceding the time of observation but no precipitation is observed at the aerodrome, the abbreviation “TS” shall be used without qualification. Freezing FZ — Supercooled water droplets or precipitation, used with types of present weather phenomena in accordance with the templates shown in Tables A3-1 and A3-2. Note. — At aerodromes with human observers, lightning detection equipment may supplement human observations. For aerodromes with automatic observing systems, guidance on the use of lightning detection equipment intended for thunderstorm reporting is given in the Manual on Automatic Meteorological Observing Systems at Aerodromes (Doc 9837). 4.4.2.6 In local routine reports, local special reports, METAR and SPECI, the following characteristics of present weather phenomena, as necessary, should be reported, using their respective abbreviations and relevant criteria, as appropriate: Shower SH — Used to report showers in accordance with the templates shown in Tables A3-1 and A3-2. Showers observed in the vicinity of the aerodrome (see 4.4.2.8) should be reported as “VCSH” without qualification regarding type or intensity of precipitation. Blowing BL — Used in accordance with the templates shown in Tables A3-1 and A3-2 with types of present weather phenomena raised by the wind to a height of 2 m (6 ft) or more above the ground. Low drifting DR — Used in accordance with the templates shown in Tables A3-1 and A3-2 with types of present weather phenomena raised by the wind to less than 2 m (6 ft) above ground level. Shallow MI — Less than 2 m (6 ft) above ground level. Patches BC — Fog patches randomly covering the aerodrome.Partial PR — A substantial part of the aerodrome covered by fog while the remainder is clear. 4.4.2.7 In automated local routine reports, local special reports, METAR and SPECI, when showers (SH) referred to in 4.4.2.6 cannot be determined based upon a method that takes account of the presence of convective cloud, the precipitation should not be characterized by SH. 4.4.2.8 In local routine reports, local special reports, METAR and SPECI, the relevant intensity or, as appropriate, the proximity to the aerodrome of the reported present weather phenomena should be indicated as follows: 4.4.2.9 In local routine reports, local special reports, METAR and SPECI: a) one or more, up to a maximum of three, of the present weather abbreviations given in 4.4.2.3 and 4.4.2.4 shall be used, as necessary, together with an indication, where appropriate, of the characteristics given in 4.4.2.5 and 4.4.2.6 and intensity or proximity to the aerodrome given in 4.4.2.8, so as to convey a complete description of the present weather of significance to flight operations; b) the indication of intensity or proximity, as appropriate, shall be reported first followed respectively by the characteristics and the type of weather phenomena; and c) where two different types of weather are observed, they shall be reported in two separate groups, where the intensity or proximity indicator refers to the weather phenomenon which follows the indicator. However, different types of precipitation occurring at the time of observation shall be reported as one single group with the dominant type of precipitation reported first and preceded by only one intensity qualifier which refers to the intensity of the total precipitation. 4.4.2.10 In automated local routine reports, local special reports, METAR and SPECI, the present weather should be replaced by “//” when the present weather cannot be observed by the automatic observing system due to a temporary failure of the system/sensor. 4.5 Clouds 4.5.1 Siting When instrumented systems are used for the measurement of the cloud amount and the height of cloud base, representative observations should be obtained by the use of sensors appropriately sited. For local routine and special reports, in the case of aerodromes with precision approach runways, sensors for cloud amount and height of cloud base should be sited to give the best practicable indications of the cloud amount and height of cloud base at the threshold of the runway in use. For that purpose, a sensor should be installed at a distance of less than 1 200 m (4 000 ft) before the landing threshold.4.5.2 Display When automated equipment is used for the measurement of the height of cloud base, height of cloud base display(s) should be located in the meteorological station with corresponding display(s) in the appropriate air traffic services units. The displays in the meteorological station and in the air traffic services units should relate to the same sensor, and where separate sensors are required as specified in 4.5.1, the displays should clearly identify the area monitored by each sensor. 4.5.3 Reference level The height of cloud base shall be reported above aerodrome elevation. When a precision approach runway is in use which has a threshold elevation 15 m (50 ft) or more below the aerodrome elevation, local arrangements shall be made in order that the height of cloud bases reported to arriving aircraft shall refer to the threshold elevation. In the case of reports from offshore structures, the height of cloud base shall be given above mean sea level. 4.5.4 Reporting 4.5.4.1 In local routine reports, local special reports, METAR and SPECI, the height of cloud base shall be reported in steps of 30 m (100 ft) up to 3000 m (10000 ft). 4.5.4.2 At aerodromes where low-visibility procedures are established for approach and landing, as agreed between the meteorological authority and the appropriate ATS authority, in local routine and special reports the height of cloud base should be reported in steps of 15 m (50 ft) up to and including 90 m (300 ft) and in steps of 30 m (100 ft) between 90 m (300 ft) and 3 000 m (10000 ft), and the vertical visibility in steps of 15 m (50 ft) up to and including 90 m (300 ft) and in steps of 30 m (100 ft) between 90 m (300 ft) and 600 m (2000 ft). 4.5.4.3 In local routine reports, local special reports, METAR and SPECI: a) cloud amount should be reported using the abbreviations “FEW” (1 to 2 oktas), “SCT” (3 to 4 oktas), “BKN” (5 to 7 oktas) or “OVC” (8 oktas); b) cumulonimbus clouds and towering cumulus clouds should be indicated as “CB” and “TCU”, respectively; c) the vertical visibility should be reported in steps of 30 m (100 ft) up to 600 m (2000 ft); d) if there are no clouds of operational significance and no restriction on vertical visibility and the abbreviation “CAVOK” is not appropriate, the abbreviation “NSC”should be used; e) when several layers or masses of cloud of operational significance are observed, their amount and height of cloud base should be reported in increasing order of the height of cloud base, and in accordance with the following criteria: 1) the lowest layer or mass, regardless of amount to be reported as FEW, SCT, BKN or OVC as appropriate; 2) the next layer or mass, covering more than 2/8 to be reported as SCT, BKN or OVC as appropriate; 3) the next higher layer or mass, covering more than 4/8 to be reported as BKN or OVC as appropriate; and 4) cumulonimbus and/or towering cumulus clouds, whenever observed and not reported in 1) to 3); f) when the cloud base is diffuse or ragged or fluctuating rapidly, the minimum height of cloud base, or cloud fragments, should be reported; and g) When an individual layer (mass) of cloud is composed of cumulonimbus and towering cumulus clouds with a common cloud base, the type of cloud should be reported as cumulonimbus only. Note. — Towering cumulus indicates cumulus congestus clouds of great vertical extent. 4.5.4.4 Any observed value in 4.5.4.1, 4.5.4.2 and 4.5.4.3 c) which does not fit the reporting scale in use shall be rounded down to the nearest lower step in the scale. 4.5.4.5 In local routine and special reports: a) the units of measurement used for the height of cloud base and vertical visibility shall be indicated; and b) When there is more than one runway in use and the heights of cloud bases are observed by instruments for these runways, the available heights of cloud bases for each runway shall be reported and the runways to which the values refer shall be indicated. 4.5.4.6 In automated local routine reports, local special reports, METAR and SPECI: a) when the cloud type cannot be observed by the automatic observing system, the cloud type in each cloud group should be replaced by “///”; b) when no clouds are detected by the automatic observing system, it should be indicated by using the abbreviation “NCD”; and c) when cumulonimbus clouds or towering cumulus clouds are detected by the automatic observing system and the cloud amount and the height of cloud base cannot beobserved, the cloud amount and/or the height of cloud base should be replaced by “///”, and d) The vertical visibility should be replaced by “///” when the sky is obscured and the value of the vertical visibility cannot be determined by the automatic observing system due to a temporary failure of the system/sensor. 4.6 Air temperature and dew-point temperature 4.6.1 Display When automated equipment is used for the measurement of air temperature and dew-point temperature, air temperature and dew-point temperature displays should be located in the meteorological station with corresponding displays in the appropriate air traffic services units. The displays in the meteorological station and in the air traffic services units should relate to the same sensors. 4.6.2 Reporting 4.6.2.1 In local routine and special reports and in METAR and SPECI, the air temperature and the dew-point temperature shall be reported in steps of whole degrees Celsius. Any observed value which does not fit the reporting scale in use shall be rounded to the nearest whole degree Celsius, with observed values involving 0.5° rounded up to the next higher whole degree Celsius. 4.6.2.2 In local routine reports, local special reports, METAR and SPECI, a temperature below 0°C shall be identified. 4.7 Atmospheric pressure 4.7.1 Display When automated equipment is used for the measurement of atmospheric pressure, QNH and, if required in accordance with 4.7.3.2 b), QFE displays relating to the barometer shall be located in the meteorological station with corresponding displays in the appropriate air traffic services units. When QFE values are displayed for more than one runway, as specified in 4.7.3.2 d), the displays shall be clearly marked to identify the runway to which the QFE value displayed refers.4.7.2 Reference level The reference level for the computation of QFE should be the aerodrome elevation. For non-precision approach runways, the thresholds of which are 2 m (7 ft) or more below the aerodrome elevation, and for precision approach runways, the QFE, if required, should refer to the relevant threshold elevation. 4.7.3 Reporting 4.7.3.1 For local routine reports, local special reports, METAR and SPECI, QNH and QFE shall be computed in tenths of hector Pascals and reported therein in steps of whole hector Pascals, using four digits. Any observed value which does not fit the reporting scale in use shall be rounded down to the nearest lower whole hector pascal. 4.7.3.2 In local routine and special reports: a) QNH shall be included; b) QFE shall be included if required by users or as agreed between the meteorological authority, the appropriate air traffic services authorities and the operators concerned, on a regular basis; c) the units of measurement used for QNH and QFE values shall be included; and d) if QFE values are required for more than one runway, the required QFE values for each runway shall be reported and the runways to which the values refer shall be indicated. 4.7.3.3 In METAR and SPECI, only QNH values shall be included. 4.8 Supplementary information 4.8.1 Reporting 4.8.1.1 In local routine reports, local special reports, METAR and SPECI, the following recent weather phenomena, i.e. weather phenomena observed at the aerodrome during the period since the last issued routine report or last hour, whichever is the shorter, but not at the time of observation, should be reported, up to a maximum of three groups, in accordance with the templates shown in Tables A3-1 and A3-2, in the supplementary information: - freezing precipitation - moderate or heavy precipitation (including showers thereof) - blowing snow - dust storm, sandstorm - thunderstorm- funnel cloud (tornado or water spout) - volcanic ash Note. — The meteorological authority, in consultation with users, may agree not to provide recent weather information where SPECI are issued. 4.8.1.2 In local routine and special reports, the following significant meteorological conditions, or combinations thereof, should be reported in supplementary information: - cumulonimbus clouds CB - thunderstorm TS - moderate or severe turbulence MOD TURB, SEV TURB - wind shear WS - hail GR - severe squall line SEV SQL - moderate or severe icing MOD ICE, SEV ICE - freezing precipitation FZDZ, FZRA - severe mountain waves SEV MTW - dust storm, sandstorm DS, SS - blowing snow BLSN - funnel cloud (tornado or water spout) FC The location of the condition should be indicated. Where necessary, additional information should be included using abbreviated plain language. 4.8.1.3 In automated local routine reports, local special reports, METAR and SPECI, in addition to the recent weather phenomena listed under 4.8.1.1, recent unknown precipitation should be reported in accordance with the template shown in Table A3-2 when the type of precipitation cannot be identified by the automatic observing system. Note. — The meteorological authority, in consultation with users, may agree not to provide recent weather information where SPECI are issued. 4.8.1.4 In METAR and SPECI, where local circumstances so warrant, information on wind shear should be added. 4.8.1.5 Until 3 November 2021, In METAR and SPECI, the following information should be included in the supplementary information, in accordance with regional air navigation agreement: a) information on sea-surface temperature and the state of the sea from aeronautical meteorological stations established on offshore structures in support of helicopter operations; andb) information on the state of the runway provided by the appropriate airport authority. Note 1.— The state of the sea is specified in the Manual on Codes (WMO- No.306), Volume I.1, Part A — Alphanumeric Codes, Code Table 3700. Note 2.— The state of the runway is specified in Manual on Codes (WMO- No.306), Volume I.1, Part A — Alphanumeric Codes, Code Tables 0366, 0519, 0919 and 1079. 4.8.1.6 As of 4 November 2021, in METAR and SPECI, information on sea-surface temperature, and the state of the sea or the significant wave height, from aeronautical meteorological stations established on offshore structures in support of helicopter operations should be included in the supplementary information, in accordance with regional air navigation agreement. Note. — The state of the sea is specified in the Manual on Codes (WMO-No.306), Volume I.1, Part A — Alphanumeric Codes, Code Table 3700.Table A3-1. Template for the local routine (MET REPORT) and local special (SPECIAL) reports Key: M = inclusion mandatory, part of every message; C = inclusion conditional, dependent on meteorological conditions; O = inclusion optional. Note 1.— The ranges and resolutions for the numerical elements included in local routine and special reports are shown in Table A3-4 of this appendix. Note 2.— The explanations for the abbreviations can be found in the Procedures for Air Navigation Services — ICAO Abbreviations and Codes (PANS-ABC, Doc 8400). Element as specified in Chapter 4 Detailed content Template(s) Examples Identification of the Type of report MET REPORT or SPECIAL MET REPORT type of report (M) SPECIAL Location indicator (M) ICAO location indicator (M) nnnn YUDO1 Time of the Day and actual time of the nnnnnnZ 221630Z observation (M) observation in UTC Identification of an Automated report identifier AUTO AUTO automated report (C) (C) Surface wind (M) Name of the element (M) WIND WIND 240/4MPS (WIND 240/8KT) Runway (O)2 RWY nn[L] or RWY nn[C] or RWY nn[R] Runway section (O)3 TDZ WIND RWY 18 TDZ 190/6MPS Wind direction (M) nnn/ VRB BTN nnn/ C (WIND RWY 18 TDZ 190/12KT) AND nnn/ A or VRB L WIND VRB1MPS WIND CALM M (WIND VRB2KT) Wind speed (M) [ABV]n[n][n]MPS (or [ABV]n[n]KT) WIND VRB BTN 350/ AND 050/1MPS Significant speed MAX[ABV]nn[n] MNMn[n] (WIND VRB BTN 350/ AND 050/2KT) variations (C)4 WIND 270/ABV49MPS Significant directional VRB BTN nnn/ — (WIND 270/ABV99KT) variations (C)5 AND nnn/ Runway section (O)3 MID WIND 120/3MPS MAX9 MNM2Wind direction (O)3 nnn/ VRB BTN nnn/ C (WIND 120/6KT MAX18 MNM4) AND nnn/ A or VRB L WIND 020/5MPS VRB BTN 350/ AND 070/ M (WIND 020/10KT VRB BTN 350/ AND 070/) Wind speed (O)3 [ABV]n[n][n]MPS (or [ABV]n[n]KT) Significant speed MAX[ABV]nn[n] MNMn[n] WIND RWY 14R MID 140/6MPS variations (C)4 (WIND RWY 14R MID 140/12KT) Significant directional VRB BTN nnn/ — WIND RWY 27 TDZ 240/8MPS variations (C)5 AND nnn/ MAX14 MNM5 END 250/7MPS Runway section (O)3 END (WIND RWY 27 TDZ 240/16KT Element as specified in Chapter 4 Detailed content Template(s) Examples Wind direction (O)3 nnn/ VRB BTN nnn/ C MAX28 MNM10 END 250/14KT) AND nnn/ A or VRB L M Wind speed (O)3 [ABV]n[n][n]MPS (or [ABV]n[n]KT) Significant speed MAX[ABV]nn[n] MNMn[n] variations (C)4 Significant directional VRB BTN nnn/ — variations (C)5 AND nnn/ Visibility (M) Name of the element (M) VIS C VIS 350M CAVOK A VIS 7KM Runway (O)2 RWY nn[L] or RWY nn[C] or RWY nn[R] V VIS 10KM Runway section (O)3 TDZ O VIS RWY 09 TDZ 800M END 1200M Visibility (M) n[n][n][n]M or n[n]KM K VIS RWY 18C TDZ 6KM RWY 27 TDZ 4000M Runway section (O)3 MID Visibility (O)3 n[n][n][n]M or n[n]KM Runway section (O)3 END Visibility (O)3 n[n][n][n]M or n[n]KM Runway visual range Name of the element (M) RVR RVR RWY 32 400M (C)6 Runway (C)7 RWY nn[L] or RWY nn[C] or RWY nn[R] RVR RWY 20 1600M RVR RWY 10L BLW 50M Runway section (C)8 TDZ RVR RWY 14 ABV 2000M Runway visual range (M) [ABV or BLW] nn[n][n]M RVR RWY 10 BLW 150M RVR RWY 12 ABV 1200M Runway section (C)8 MID RVR RWY 12 TDZ 1100M MID ABV 1400M Runway visual range (C)8 [ABV or BLW] nn[n][n]M RVR RWY 16 TDZ 600M MID 500M END 400M RVR RWY 26 500M RWY 20 800M Runway section (C)8 END Runway visual range (C)8 [ABV or BLW] nn[n][n]M Present weather (C)9, 10 Intensity of present weather FBL or — (C)9 MOD or HVYCharacteristics and type of DZ or RA or FG or BR or MOD RA present weather (C)9,11 SN or SG or SA or DU or HVY TSRA PL or DS or HZ or FU or HVY DZ SS or FZDZ or VA or SQ or FBL SN FZUP12 or FC13 or PO or TS or HZ FZRA or SHGR or BCFG or BLDU or FG SHGS or SHRA or BLSA or BLSN or VA SHSN or SHUP12 or DRDU or DRSA or MIFG TSGR or TSGS or DRSN or FZFG or TSRA or TSSN or MIFG or PRFG or HVY TSRASN TSUP12 or UP12 //12 FBL SNRA FBL DZ FG HVY SHSN BLSN HVY TSUP // Element as specified in Chapter 4 Detailed content Template(s) Examples Cloud (M)14 Name of the element (M) CLD CLD NSC CLD SCT 300M OVC 600M Runway (O)2 RWY nn[L] or RWY nn[C] or RWY nn[R] (CLD SCT 1000FT OVC 2000FT) Cloud amount (M) or FEW or OBSC NSC or NCD12 vertical visibility (O)9 SCT or CLD OBSC VER VIS 150M BKN or (CLD OBSC VER VIS 500FT) OVC or CLD BKN TCU 270M ///12 (CLD BKN TCU 900FT) Cloud type (C)9 CB or — CLD RWY 08R BKN 60M RWY 26 BKN 90M TCU or (CLD RWY 08R BKN 200FT RWY 26 BKN 300FT) ///12 CLD /// CB ///M (CLD /// CB ///FT) CLD /// CB 400M (CLD /// CB 1200FT) Height of cloud base or n[n][n][n]M [VER VIS CLD NCD the value of vertical (or n[n][n]M(or visibility (C)9 n[n][n][n]FT) VER VIS or n[n][n][n]FT)] ///M or (or VER VIS ///FT)12 ///M (or VER VIS ///FT)12 Air temperature (M) Name of the element (M) T T17 Air temperature (M) [MS]nn TMS08 Dew-point Name of the element (M) DP DP15 temperature (M) Dew-point temperature (M) [MS]nn DPMS18 Pressure values (M) Name of the element (M) QNH QNH 0995HPA QNH (M) nnnnHPA QNH 1009HPA Name of the element (O) QFE QNH 1022HPA QFE 1001HPA QFE (O) [RWY nn[L] or RWY nn[C] or RWY nn[R]] nnnnHPA QNH 0987HPA QFE RWY 18 0956HPA [RWY nn[L] or RWY nn[C] or RWY nn[R] nnnnHPA] RWY 24 0955HPASupplementary Significant meteorological CB or TS or MOD TURB or SEV TURB or WS or GR or FC IN APCH information (C)9 phenomena (C)9 SEV SQL or MOD ICE or SEV ICE or FZDZ or FZRA or WS IN APCH 60M-WIND 360/13MPS SEV MTW or SS or DS or BLSN or FC15 WS RWY 12 Location of the IN APCH [n[n][n][n]M-WIND nnn/n[n]MPS] or REFZRA phenomena (C)9 IN CLIMB-OUT [n[n][n][n]M-WIND nnn/n[n]MPS] CB IN CLIMB-OUT RETSRA (IN APCH [n[n][n][n]FT-WIND nnn/n[n]KT] or IN CLIMB-OUT [n[n][n][n]FT-WIND nnn/n[n]KT]) or RWY nn[L] or RWY nn[C] or RWY nn[R] Recent weather (C)9, 10 RERASN or REFZDZ or REFZRA or REDZ or RE[SH]RA or RE[SH]SN or RESG or RESHGR or RESHGS or REBLSN or RESS or REDS or RETSRA or RETSSN or RETSGR or RETSGS or REFC or REPL or REUP12 or REFZUP12 or RETSUP12 or RESHUP12 or REVA or RETS Trend forecast (O)16 Name of the element (M) TREND TREND NOSIG TREND BECMG FEW 600M (TREND BECMG FEW 2000FT) Change indicator (M)17 NOSIG BECMG or TEMPO Period of change (C)9 FMnnnn and/or TLnnnn or ATnnnn TREND TEMPO 250/18 MPS MAX25 Wind (C)9 nnn/[ABV]n[n][n]MPS [MAX[ABV]nn[n]] (TREND TEMPO 250/36KT MAX50) (or nnn/[ABV]n[n]KT [MAX[ABV]nn]) TREND BECMG AT1800 VIS 10KM NSW Visibility (C)9 VIS n[n][n][n]M or C TREND BECMG TL1700 VIS 800M FG VIS n[n]KM A TREND BECMG FM1030 TL1130 CAVOK V Weather phenomenon: FBL or — NSW O intensity (C)9 MOD or TREND TEMPO TL1200 VIS 600M BECMG HVY K AT1230 VIS 8KM NSW CLD NSC Element as specified in Chapter 4 Detailed content Template(s) Examples Weather phenomenon: DZ or FG or TREND TEMPO FM0300 TL0430 MOD FZRA characteristics and RA or BR or TREND BECMG FM1900 VIS 500M HVY SNRA type (C)9, 10, 11 SN or SA or TREND BECMG FM1100 MOD SN TEMPO SG or DU or FM1130 BLSN PL or HZ or DS or FU or TREND BECMG AT1130 CLD OVC 300M SS or VA or (TREND BECMG AT1130 CLD OVC 1000FT) FZDZ or SQ or FZRA or PO or TREND TEMPO TL1530 HVY SHRA CLD BKN CB SHGR or FC or 360M SHGS or TS or (TREND TEMPO TL1530 HVY SHRA CLD BKN CB SHRA or BCFG or 1200FT) SHSN or BLDU or TSGR or BLSA or TSGS or BLSN or TSRA or DRDU or TSSN DRSA or DRSN or FZFG or MIFG or PRFG Name of the element (C)9 CLD Cloud amount and vertical FEW or OBSC NSC visibility (C)9,14 SCT or BKN or OVC Cloud type (C)9,14 CB or — TCUHeight of cloud base or the n[n][n][n] [VER VIS value of vertical visibility M (or n[n][n]M (C)9,14 n[n][n][n] (or VER FT) VIS n[n][n][n] FT)] Notes. — 1. Fictitious location. 2. Optional values for one or more runways. 3. Optional values for one or more sections of the runway. 4. To be included in accordance with 4.1.5.2 c). 5. To be included in accordance with 4.1.5.2 b) 1). 6. To be included if visibility or runway visual range < 1 500 m. 7. To be included in accordance with 4.3.6.4 d). 8. To be included in accordance with 4.3.6.4 c). 9. To be included whenever applicable. 10. One or more, up to a maximum of three groups, in accordance with 4.4.2.9 a), 4.8.1.1 and Appendix 5, 2.2.4.3. 11. Precipitation types listed under 4.4.2.3 a) may be combined in accordance with 4.4.2.9 c) and Appendix 5, 2.2.4.1. Only moderate or heavy precipitation to be indicated in trend forecasts in accordance with Appendix 5, 2.2.4.1. 12. For automated reports only. 13. Heavy used to indicate tornado or waterspout; moderate used to indicate funnel cloud not reaching the ground. 14. Up to four cloud layers in accordance with 4.5.4.3 e). 15. Abbreviated plain language may be used in accordance with 4.8.1.2. 16. To be included in accordance with Chapter 6, 6.3.2. 17. Number of change indicators to be kept to a minimum in accordance with Appendix 5, 2.2.1, normally not exceeding three groups. Table A3-2. Template for METAR and local SPECI (applicable until 3 November 2021) Key: M = inclusion mandatory, part of every message; C = inclusion conditional, dependent on meteorological conditions conditions or method of observation; O = inclusion optional. Note 1.— The ranges and resolutions for the numerical elements included in METAR and SPECI are shown in Table A3-5 of this appendix. Note 2.— The explanations for the abbreviations can be found in the PANS-ABC (Doc 8400). Element as specified in Chapter 4 Detailed content Template(s) Examples Identification of the Type of report (M) METAR, METAR COR, SPECI or SPECI COR METAR type of report (M) METAR COR SPECI Location indicator (M) ICAO location indicator (M) nnnn YUDO1 Time of the Day and actual time of the nnnnnnZ 221630Z observation (M) observation in UTC (M) Identification of an Automated or missing report AUTO or NIL AUTO automated or missing identifier (C) NIL report (C)2END OF METAR IF THE REPORT IS MISSING. Surface wind (M) Wind direction (M) nnn VRB 24004MPS VRB01MPS (24008KT) (VRB02KT) Wind speed (M) [P]nn[n] 19006MPS (19012KT) 00000MPS (00000KT) 140P49MPS (140P99KT) Significant speed variations (C)3 G[P]nn[n] 12003G09MPS (12006G18KT) Units of measurement (M) MPS (or KT) 24008G14MPS (24016G28KT) Significant directional nnnVnnn — 02005MPS 350V070 variations (C)4 (02010KT 350V070) Visibility (M) Prevailing or minimum nnnn C 0350 CAVOK visibility (M)5 A 7000 V 9999 O 0800 K Minimum visibility and nnnn[N] or nnnn[NE] or nnnn[E] or nnnn[SE] or 2000 1200NW direction of the minimum nnnn[S] or nnnn[SW] or nnnn[W] or nnnn[NW] 6000 2800E visibility (C)6 6000 2800 Runway visual range Name of the element (M) R R32/0400 (C)7 Runway (M) nn[L]/or nn[C]/or nn[R]/ R12R/1700 R10/M0050 R14L/P2000 Runway visual range (M) [P or M]nnnn R16L/0650 R16C/0500 R16R/0450 R17L/0450 Runway visual range past U, D or N R12/1100U tendency (C)8 R26/0550N R20/0800D R12/0700 Element as specified in Chapter 4 Detailed content Template(s) Examples Present weather Intensity or proximity of present – or + — VC (C)2, 9 weather (C)10 Characteristics and type of DZ or RA or FG or BR or FG or PO or RA HZ VCFG present weather (M)11 SN or SG or SA or DU or FC or DS or +TSRA FG VCSH PL or DS or HZ or FU or SS or TS or +DZ VA VCTS SS or VA or SQ or SH or BLSN or –SN MIFG VCBLSA FZDZ or PO or TS or BLSA or FZRA or BCFG or BLDU or VA +TSRASN FZUP12 or BLDU or –SNRA FC13 or BLSA or SHGR or BLSN or DZ FG SHGS or DRDU or +SHSN BLSN SHRA or DRSA or UP SHSN or DRSN or FZUP SHUP12 or FZFG or TSUP FZUP TSGR or MIFG or TSGS or PRFG or //12 // TSRA or TSSN or TSUP12 or UP12 Cloud (M)14 Cloud amount and FEWnnn or VVnnn or NSC or FEW015 VV005 height of cloud base or SCTnnn or VV///12 NCD12 OVC030 VV/// NSC vertical visibility (M) BKNnnn or OVCnnn or SCT010 OVC0 20 FEW///12 or SCT///12 or BKN/// ///015 BKN///12 or OVC///12 or ///nnn12 or //////12Cloud type (C)2 CB or — BKN009TCU NCD TCU or ///12 SCT008 BKN025CB BKN025/// ///CB Air and dew-point Air and dew-point temperature [M]nn/[M]nn 17/10 temperature (M) (M) 02/M08 M01/M10 Pressure values (M) Name of the element (M) Q Q0995 Q1009 QNH (M) nnnn Q1022 Q0987 Supplementary Recent weather (C)2, 9 RERASN or REFZDZ or REFZRA or REDZ or RE[SH]RA or REFZRA information (C) RE[SH]SN or RESG or RESHGR or RESHGS or REBLSN or RETSRA RESS or REDS or RETSRA or RETSSN or RETSGR or RETSGS or RETS or REFC or REVA or REPL or REUP12 or REFZUP12 or RETSUP12 or RESHUP12 Wind shear (C)2 WS Rnn[L] or WS Rnn[C] or WS Rnn[R] or WS ALL RWY WS R03 WS ALL RWY WS R18C Sea-surface temperature and W [M]nn/Sn or W[M]nn/Hn[n][n] W15/S2 state of the sea or significant W12/H75 wave height (C)15 Element as specified in Chapter 4 Detailed content Template(s) Examples State Runway designator R nn[L]/ or Rnn[C]/ or Rnn[R]/ R/SNOCLO R99/421594 of the (M) R/SNOCLO runway R14L/CLRD// Runway deposits (M) n or / CLRD// (C)16 Extent of runway n or / contamination (M) Depth of deposit (M) nn or // Friction coefficient or nn or // braking action (M) Trend forecast (O)17 Change indicator (M)18 NOSIG BECMG or TEMPO NOSIG BECMG FEW020 Period of change (C)2 FMnnnn and/or TEMPO 25018G25MPS TLnnnn (TEMPO 25036G50KT) or ATnnnn BECMG FM1030 TL1130 CAVOK Wind (C)2 nnn[P]nn[n][G[P]nn[n]]MPS (or nnn[P]nn[G[P]nn]KT) BECMG TL1700 0800 FG Prevailing visibility (C)2 nnnn C BECMG AT1800 9000 NSW A Weather phenomenon: – or + — N V intensity (C)10 SWeather phenomenon: DZ or RA or FG or BR or W O BECMG FM1900 0500 +SNRA characteristics and SN or SG or SA or DU or K BECMG FM1100 SN TEMPO FM1130 BLSN type (C)2, 9, 11 PL or DS or HZ or FU or SS or VA or SQ or TEMPO FM0330 TL0430 FZRA FZDZ or PO or FC or TEMPO TL1200 0600 BECMG AT1200 8000 FZRA or TS or NSW NSC SHGR or BCFG or SHGS or BLDU or BECMG AT1130 OVC010 SHRA or BLSA or SHSN or BLSN or TEMPO TL1530 +SHRA BKN012CB TSGR or DRDU or TSGS or DRSA or TSRA or DRSN or TSSN FZFG or MIFG or PRFG Cloud amount and height of cloud FEWnnn or VVnnn or N base or vertical visibility (C)2, 14 SCTnnn or VV/// S BKNnnn or C OVCnnn Cloud type (C)2,14 CB or TCU — Notes. - 1. Fictitious location. 2. To be included whenever applicable. 3. To be included in accordance with 4.1.5.2 c). 4. To be included in accordance with 4.1.5.2 b) 1). 5. To be included in accordance with 4.2.4.4 b). 6. To be included in accordance with 4.2.4.4 a). 7. To be included if visibility or runway visual range < 1 500 m; for up to a maximum of four runways in accordance with 4.3.6.5 b). 8. To be included in accordance with 4.3.6.6. 9. One or more, up to a maximum of three groups, in accordance with 4.4.2.9 a), 4.8.1.1 and Appendix 5, 2.2.4.1. 10. To be included whenever applicable; no qualifier for moderate intensity in accordance with 4.4.2.8. 11. Precipitation types listed under 4.4.2.3 a) may be combined in accordance with 4.4.2.9 c) and Appendix 5, 2.2.4.1. Only moderate or heavy precipitation to be indicated in trend forecasts in accordance with Appendix 5, 2.2.4.1. 12. For automated reports only. 13. Heavy used to indicate tornado or waterspout; moderate (no qualifier) to indicate funnel cloud not reaching the ground. 14. Up to four cloud layers in accordance with 4.5.4.3 e) 15. To be included in accordance with 4.8.1.5 a). 16. To be included in accordance with 4.8.1.5 b) until 3 November 2021. 17. To be included in accordance with Chapter 6, 6.3.2. 18. Number of change indicators to be kept to a minimum in accordance with Appendix 5, 2.2.1, normally not exceeding three groups. Table A3-2. Template for METAR and local SPECI (applicable as of 4 November 2021) Key: M = inclusion mandatory, part of every message; C = inclusion conditional, dependent on meteorological conditions; O = inclusion optional.Note 1.— The ranges and resolutions for the numerical elements included in local routine and special reports are shown in Table A3-4 of this appendix. Note 2.— The explanations for the abbreviations can be found in the PANS-ABC (Doc 8400). Element as specified in Chapter 4 Detailed content Template(s) Examples Identification of the Type of report (M) METAR, METAR COR, SPECI or SPECI COR METAR type of report (M) METAR COR SPECI Location indicator (M) ICAO location indicator (M) nnnn YUDO1 Time of the Day and actual time of the nnnnnnZ 221630Z observation (M) observation in UTC (M) Identification of an Automated or missing report AUTO or NIL AUTO automated or missing identifier (C) NIL report (C)2 END OF METAR IF THE REPORT IS MISSING. Surface wind (M) Wind direction (M) Nnn or III12 VRB 24004MPS VRB01MPS III10MPS Wind speed (M) [P]nn[n] or II12 (24008KT) (VRB02KT) 240IIKT 19006MPS IIIIKT (19012KT) 00000MPS (00000KT) 140P49MPS (140P99KT) Significant speed variations (C)3 G[P]nn[n] 12003G09MPS (12006G18KT) Units of measurement (M) MPS (or KT) 24008G14MPS (24016G28KT) Significant directional nnnVnnn — 02005MPS 350V070 variations (C)4 (02010KT 350V070) Visibility (M) Prevailing or minimum Nnnn or IIII12 C 0350 IIII CAVOK visibility (M)5 A 7000 V 9999 O 0800 K Minimum visibility and nnnn[N] or nnnn[NE] or nnnn[E] or nnnn[SE] or 2000 1200NW direction of the minimum nnnn[S] or nnnn[SW] or nnnn[W] or nnnn[NW] 6000 2800E visibility (C)6 6000 2800 Element as specified in Chapter 4 Detailed content Template(s) Examples Runway visual range Name of the element (M) R R32/0400 (C)7 Runway (M) nn[L]/or nn[C]/or nn[R]/ R12R/1700 R10/M0050 R14L/P2000 Runway visual range (M) [P or M]nnnn or IIII12 R16L/0650 R16C/0500 R16LIIII R10IIII R16R/0450 R17L/0450 Runway visual range past U, D or N R12/1100U tendency (C)8 R26/0550N R20/0800D R12/0700 Present weather Intensity or proximity of present – or + — VC (C)2, 9 weather (C)10 Characteristics and type of DZ or RA or FG or BR or FG or PO or RA HZ VCFG present weather (M)11 SN or SG or SA or DU or FC or DS or +TSRA FG VCSH PL or DS or HZ or FU or SS or TS or +DZ VA VCTS SS or VA or SQ or SH or BLSN or –SN MIFG VCBLSA FZDZ or PO or TS or BLSA or FZRA or BCFG or BLDU or VA +TSRASN FZUP12 or BLDU or –SNRAFC13 or BLSA or SHGR or BLSN or DZ FG SHGS or DRDU or +SHSN BLSN SHRA or DRSA or UP SHSN or DRSN or FZUP SHUP12 or FZFG or TSUP FZUP TSGR or MIFG or TSGS or PRFG or //12 // TSRA or TSSN or TSUP12 or UP12 Cloud (M)14 Cloud amount and FEWnnn or VVnnn or NSC or FEW015 VV005 height of cloud base or SCTnnn or VV///12 NCD12 OVC030 VV/// NSC vertical visibility (M) BKNnnn or OVCnnn or SCT010 OVC0 20 FEW///12 or SCT///12 or BKN/// ///015 BKN///12 or OVC///12 or ///nnn12 or //////12 Cloud type (C)2 CB or — BKN009TCU NCD TCU or ///12 SCT008 BKN025CB BKN025/// III///CB ///////// BKN///TCU Air and dew-point Air and dew-point temperature [M]nn/[M]nn or ///[M]nn12 or [M]nn///12 or /////12 17/10 ///10 17/// ///// temperature (M) (M) 02/M08 M01/M10 Pressure values (M) Name of the element (M) Q Q0995 QNH (M) Nnnn or IIII12 Q1009 Q1022 QIIII Q0987 Element as specified in Chapter 4 Detailed content Template(s) Examples Supplementary Recent weather (C)2, 9 RERASN or REFZDZ or REFZRA or REDZ or RE[SH]RA or REFZRA information (C) RE[SH]SN or RESG or RESHGR or RESHGS or REBLSN or RETSRA RESS or REDS or RETSRA or RETSSN or RETSGR or RETSGS or RETS or REFC or REVA or REPL or REUP12 or REFZUP12 or RETSUP12 or RESHUP12 or REII12 Wind shear (C)2 WS Rnn[L] or WS Rnn[C] or WS Rnn[R] or WS ALL RWY WS R03 WS ALL RWY WS R18C Sea-surface temperature and W[M]nn/Sn or W///Sn or W[M]nn/S/ or W[M]nn/Hn[n][n] or W15/S2 state of the sea or significant W///Hn[n][n] or W[M]nn/H/// W12/H75 wave height (C)15 W///S3 WM01/S/ W///H104 W17/H/// W///H/// W///S/ Trend forecast (O)16 Change indicator (M)17 NOSIG BECMG or TEMPO NOSIG BECMG FEW020 Period of change (C)2 FMnnnn and/or TEMPO 25018G25MPS TLnnnn (TEMPO 25036G50KT) or ATnnnnWind (C)2 nnn[P]nn[n][G[P]nn[n]]MPS BECMG FM1030 TL1130 CAVOK (or nnn[P]nn[G[P]nn]KT) BECMG TL1700 0800 FG Prevailing visibility (C)2 nnnn C A BECMG AT1800 9000 NSW Weather phenomenon: – or + — N V intensity (C)10 S O BECMG FM1900 0500 +SNRA W Weather phenomenon: DZ or RA or FG or BR or K BECMG FM1100 SN TEMPO FM1130 BLSN characteristics and SN or SG or SA or DU or type (C)2, 9, 11 PL or DS or HZ or FU or TEMPO FM0330 TL0430 FZRA SS or VA or SQ or TEMPO TL1200 0600 BECMG AT1200 8000 FZDZ or PO or FC or NSW NSC FZRA or TS or SHGR or BCFG or BECMG AT1130 OVC010 SHGS or BLDU or SHRA or BLSA or TEMPO TL1530 +SHRA BKN012CB SHSN or BLSN or TSGR or DRDU or TSGS or DRSA or TSRA or DRSN or TSSN FZFG or MIFG or PRFG Cloud amount and height of cloud FEWnnn or VVnnn or N base or vertical visibility (C)2, 14 SCTnnn or VV/// S BKNnnn or C OVCnnn Cloud type (C)2,14 CB or TCU — Notes. - 1. Fictitious location. 2. To be included whenever applicable. 3. To be included in accordance with 4.1.5.2 c). 4. To be included in accordance with 4.1.5.2 b) 1). 5. To be included in accordance with 4.2.4.4 b). 6. To be included in accordance with 4.2.4.4 a). 7. To be included if visibility or runway visual range < 1 500 m; for up to a maximum of four runways in accordance with 4.3.6.5 b). 8. To be included in accordance with 4.3.6.6. 9. One or more, up to a maximum of three groups, in accordance with 4.4.2.9 a), 4.8.1.1 and Appendix 5, 2.2.4.1. 10. To be included whenever applicable; no qualifier for moderate intensity in accordance with 4.4.2.8. 11. Precipitation types listed under 4.4.2.3 a) may be combined in accordance with 4.4.2.9 c) and Appendix 5, 2.2.4.1. Only moderate or heavy precipitation to be indicated in trend forecasts in accordance with Appendix 5, 2.2.4.1. 12. When a meteorological element is temporarily missing, or its value considered temporarily as incorrect, it is replaced by “/” for each digit of the abbreviation of the text message and indicated as missing for its IWXXM version. 13. Heavy used to indicate tornado or waterspout; moderate (no qualifier) to indicate funnel cloud not reaching the ground. 14. Up to four cloud layers in accordance with 4.5.4.3 e) 15. To be included in accordance with 4.8.1.5 a). 16. To be included in accordance with Chapter 6, 6.3.2. 17. Number of change indicators to be kept to a minimum in accordance with Appendix 5, 2.2.1, normally not exceeding three groups.Table A3-3. Use of change indicators in trend forecasts Change indicator Time indicator and period Meaning NOSIG — no significant changes are forecast BECMG FMn1n1n1n1 TLn2n2n2n2 the change is commence at n1n1n1n1 UTC and be completed by n2n2n2n2 UTC forecast to TLnnnn commence at the beginning of the trend forecast period and be completed by nnnn UTC FMnnnn commence at nnnn UTC and be completed by the end of the trend forecast period ATnnnn occur at nnnn UTC (specified time) — a) commence at the beginning of the trend forecast period and be completed by the end of the trend forecast period; or b) the time is uncertain TEMPO FMn1n1n1n1 TLn2n2n2n2 temporary commence at n1n1n1n1 UTC and cease by n2n2n2n2 UTC fluctuations are forecast to TLnnnn commence at the beginning of the trend forecast period and cease by nnnn UTC FMnnnn commence at nnnn UTC and cease by the end of the trend forecast period — commence at the beginning of the trend forecast period and cease by the end of the trend forecast period Table A3-4. Ranges and resolutions for the numerical elements included in local reports Element as specified in Chapter 4 Range Resolution Runway: (no units) 01 – 36 1 Wind direction: °true 010 – 360 10 Wind speed: MPS 1 – 99* 1 KT 1 – 199* 1 Visibility: M 0 – 750 50 M 800 – 4 900 100 KM 5 – 9 1 KM 10 – 0 (fixed value: 10 KM) Runway visual range: M 0 – 375 25 M 400 – 750 50 M 800 – 2 000 100 Vertical visibility: M 0 – 75** 15 M 90 – 600 30 FT 0 – 250** 50FT 300 – 2 000 100 Clouds: height of cloud base: M 0 – 75** 15 M 90 – 3 000 30 FT 0 – 250** 50 FT 300 – 10 000 100 Air temperature; °C –80 – +60 1 Dew-point temperature: QNH; QFE: hPa 0500 – 1 100 1 * There is no aeronautical requirement to report surface wind speeds of 50 m/s (100 kt) or more; however, provision has been made for reporting wind speeds up to 99 m/s (199 kt) for non-aeronautical purposes, as necessary. ** Under circumstances as specified in 4.5.4.2; otherwise a resolution of 30 m (100 ft) is to be used. Table A3-4. Ranges and resolutions for the numerical elements included in METAR and SPECI Element as specified in Chapter 4 Range Resolution Runway: (no units) 01 – 36 1 Wind direction: °true 000 – 360 10 Wind speed: MPS 00 – 99* 1 KT 00 – 199* 1 Visibility: M 0000 – 0750 50 M 0800 – 4 900 100 M 5 000 – 9 000 1 000 M 10 000 – 0 (fixed value: 9 999) Runway visual range: M 0000 – 0375 25 M 0400 – 0750 50 M 0800 – 2 000 100 Vertical visibility: 30’s M (100’s FT) 000 – 020 1 Clouds: height of cloud base: 30’s M (100’s FT) 000 – 100 1Air temperature; Dew-point temperature: °C –80 – +60 1 QNH: hPa 0850 – 1 100 1 Sea-surface temperature: °C –10 – +40 1 State of the sea: (no units) 0 – 9 1 Significant wave height: M 0 – 999 0.1 State of the runway Runway designator: (no units) 01 – 36; 88; 99 1 [Until 3 November 2021] Runway deposits: (no units) 0 – 9 1 Extent of runway contamination: (no units) 1; 2; 5; 9 — Depth of deposit: (no units) 00 – 90; 92 – 99 1 Friction coefficient/braking action: (no units) 00 – 95; 99 1 * There is no aeronautical requirement to report surface wind speeds of 50 m/s (100 kt) or more; however, provision has been made for reporting wind speeds up to 99 m/s (199 kt) for non-aeronautical purposes, as necessary. Example A3-1. Routine report a) Local routine report (same location and weather conditions as METAR): MET REPORT YUDO 221630Z WIND 240/4MPS VIS 600M RVR RWY 12 TDZ 1000M MOD DZ FG CLD SCT 300M OVC 600M T17 DP16 QNH 1018HPA TREND BECMG TL1700 VIS 800M FG BECMG AT1800 VIS 10KM NSW b) METAR for YUDO (Donlon/International) *: METAR YUDO 221630Z 24004MPS 0600 R12/1000U DZ FG SCT010 OVC020 17/16 Q1018 BECMG TL1700 0800 FG BECMG AT1800 9999 NSW Meaning of both reports: Routine report for Donlon/International* issued on the 22nd of the month at 1630 UTC; surface wind direction 240 degrees; wind speed 4 metres per second; visibility (along the runway(s) in the local routine report; prevailing visibility in METAR) 600 metres; runway visual range representative of the touchdown zone for runway 12 is 1 000 metres and the runway visual range values have shown an upward tendency during previous 10 minutes (runway visual range tendency to be included inMETAR only); and moderate drizzle and fog; scattered cloud at 300 metres; overcast at 600 metres; air temperature 17 degrees Celsius; dew-point temperature 16 degrees Celsius; QNH 1 018 hectopascals; trend during next 2 hours, visibility (along the runway(s) in the local routine report; prevailing visibility in METAR) becoming 800 metres in fog by 1700 UTC; at 1800 UTC visibility (along the runway(s) in the local routine report; prevailing visibility in METAR) becoming 10 kilometres or more and nil significant weather. * Fictitious location Note. — In this example, the primary units “metre per second” and “metre” were used for wind speed and height of cloud base, respectively. However, in accordance with Annex 5, the corresponding non-SI alternative units “knot” and “foot” may be used instead. Example A3-2. Special report a) Local special report (same location and weather conditions as SPECI): SPECIAL YUDO 151115Z WIND 050/25KT MAX37 MNM10 VIS 1200M RVR RWY 05 ABV 1800M HVY TSRA CLD BKN CB 500FT T25 DP22 QNH 1008HPA TREND TEMPO TL1200 VIS 600M BECMG AT1200 VIS 8KM NSW NSC b) SPECI for YUDO (Donlon/International)*: SPECI YUDO 151115Z 05025G37KT 3000 1200NE+TSRA BKN005CB 25/22 Q1008 TEMPO TL1200 0600 BECMG AT1200 8000 NSW NSC Meaning of both reports: Special report for Donlon/International* issued on the 15th of the month at 1115 UTC; surface wind direction 050 degrees; wind speed 25 knots gusting between 10 and 37 knots (minimum wind speed not to be included in SPECI) visibility 1 200 metres (along the runway(s) in the local special report); prevailing visibility 3 000 metres (in SPECI) with minimum visibility 1 200 metres to north east (directional variations to be included in SPECI only); runway visual range above 1 800 metreson runway 05 (runway visual range not required in SPECI with prevailing visibility of 3 000 metres); thunderstorm with heavy rain; broken cumulonimbus cloud at 500 feet; air temperature 25 degrees Celsius; dew-point temperature 22 degrees Celsius; QNH 1 008 hectopascals; trend during next 2 hours, visibility (along the runway(s) in the local special report; prevailing visibility in SPECI) temporarily 600 metres from 1115 to 1200, becoming at 1200 UTC visibility (along the runway(s) in the local special report; prevailing visibility in SPECI) 8 kilometres, thunderstorm ceases and nil significant weather and nil significant cloud. * Fictitious location Note.— In this example, the non-SI alternative units “knot” and “foot” were used for wind speed and height of cloud base, respectively. However, in accordance with Annex 5, the corresponding primary units “metres per second” and “metre” may be used instead. Example A3-3. Volcanic activity report VOLCANIC ACTIVITY REPORT YUSB* 231500 MT TROJEEN* VOLCANO N5605 W12652 ERUPTED 231445 LARGE ASH CLOUD EXTENDING TO APPROX 30000 FEET MOVING SW Meaning: Volcanic activity report issued by Siby/Bistock meteorological station at 1500 UTC on the 23rd of the month. Mt. Trojeen volcano 56 degrees 5 minutes north 126 degrees 52 minutes west erupted at 1445 UTC on the 23rd; a large ash cloud was observed extending to approximately 30 000 feet and moving in a south-westerly direction. * Fictitious location APPENDIX 4. TECHNICAL SPECIFICATIONS RELATED TO AIRCRAFT OBSERVATIONS AND REPORTS (See Para 5 of this CAR) 1. Contents of Air-Reports 1.1 Routine air-reports by air-ground data link 1.1.1 When air-ground data link is used and automatic dependent surveillance (ADS- c) or SSR Mode S is being applied, the elements contained in routine air-reports shall be: Message type designator Aircraft identification Data block 1 LatitudeLongitude Level Time Data block 2 Wind direction Wind speed Wind quality flag Air temperature Turbulence (if available) Humidity (if available) Note. — When ADS-C or SSR Mode S is being applied, the requirements of routine air- reports may be met by the combination of the basic ADS-C/SSR Mode S data block (data block 1) and the meteorological information data block (data block 2), available from ADS- C or SSR Mode S reports. The ADS-C message format is specified in the PANS-ATM (Doc 4444), 4.11.4 and Para 13 and the SSR Mode S message format is specified in Annex 10, Volume III, Part I, Para 5. 1.1.2 When air-ground data link is used while ADS-C and SSR Mode S are not being applied, the elements contained in routine reports shall be: Message type designator Section 1 (Position information) Aircraft identification Position or latitude and longitude Time Flight level or altitude Next position and time over Ensuing significant point Section 2 (Operational information) Estimated time of arrival Endurance Section 3 (Meteorological information) Air temperature Wind direction Wind speed Turbulence Aircraft icing Humidity (if available) Note. — When air-ground data link is used while ADS-C and SSR Mode S are not beingapplied, the requirements of routine air-reports may be met by the controller-pilot data link communication (CPDLC) application entitled “Position report”. The details of this data link application are specified in the Manual of Air Traffic Services Data Link Applications (Doc 9694) and in Annex 10, Volume III, Part I. 1.2 Special air-reports by air-ground data link When air-ground data link is used, the elements contained in special air-reports shall be: Message type designator Aircraft identification Data block 1 Latitude Longitude Level Time Data block 2 Wind direction Wind speed Wind quality flag Air temperature Turbulence (if available) Humidity (if available) Data block 3 Condition prompting the issuance of a special air-report (one condition to be selected from the list presented in Table A4-1). Note 1. — The requirements of special air-reports may be met by the data link flight information service (D-FIS) application entitled “Special air-report service”. The details of this data link application are specified in Doc 9694. Note 2. — In the case of a special air-report of pre-eruption volcanic activity, Volcanic eruption or volcanic ash cloud, additional requirements are indicated in 4.2. 1.3 Special air-reports by voice communications When voice communications are used, the elements contained in special air- reports shall be: Message type designator Section 1 (Position information) Aircraft identification Position or latitude and longitude Time Level or range of levelsSection 3 (Meteorological information) Condition prompting the issuance of a special air-report, to be selected from the list presented in Table A4-1. Note 1. — Air-reports are considered routine by default. The message type designator for special air-reports is specified in the PANS-ATM (Doc 4444), Appendix 1. Note 2. — In the case of a special air-report of pre-eruption volcanic activity, volcanic eruption or volcanic ash cloud, additional requirements are indicated in 4.2. 2. Criteria for Reporting 2.1 General When air-ground data link is used, the wind direction, wind speed, wind quality flag, air temperature, turbulence and humidity included in air-reports shall be reported in accordance with the following criteria. 2.2 Wind Direction The wind direction shall be reported in terms degrees true, rounded to the nearest whole degree. 2.3 Wind speed The wind speed shall be reported in metres per second or knots, rounded to the nearest 1 m/s (1 knot). The units of measurement used for the wind speed shall be indicated. 2.4 Wind quality flag The wind quality flag shall be reported as 0 when the roll angle is less than 5 degrees and as 1 when the roll angle is 5 degrees or more. 2.5 Air temperature The air temperature shall be reported to the nearest tenth of a degree Celsius. 2.6 Turbulence The turbulence shall be reported in terms of the cube root of the eddy dissipation rate (EDR). Note. — The EDR is an aircraft-independent measure of turbulence. However, the relationship between the EDR value and the perception of turbulence is a function of aircraft type, and the mass, altitude, configuration and airspeed of the aircraft. The EDR values given below describe the severity levels for a medium-sized transport aircraft undertypical en-route conditions (i.e. altitude, airspeed and weight). 2.6.1 Routine air-reports The turbulence shall be reported during the en-route phase of the flight and shall refer to the 15-minute period immediately preceding the observation. Both the average and peak value of turbulence, together with the time of occurrence of the peak value to the nearest minute, shall be observed. The average and peak values shall be reported in terms of the cube root of EDR. The time of occurrence of the peak value shall be reported as indicated in Table A4-2. The turbulence shall be reported during the climb-out phase for the first 10 minutes of the flight and shall refer to the 30-second period immediately preceding the observation. The peak value of turbulence shall be observed. 2.6.2 Interpretation of the turbulence report Turbulence shall be considered: a) severe when the peak value of EDR equal or exceeds 0.45; b) moderate when the peak value root of EDR is equal to or above 0.20 and below 0.45 c) light when the peak value of the cube root of EDR is above 0.10 and below 0.20 and d) Nil when the peak value of the cube root of EDR is below or equal to 0.10. 2.6.3 Special air-reports Special air-reports on turbulence shall be made during any phase of the flight whenever the peak value of the cube root of EDR equal or exceeds 0.20. The special air-report on turbulence shall be made with reference to the 1-minute period immediately preceding the observation. Both the average and peak value of turbulence shall be observed. The average and peak values shall be reported in terms of the cube root of EDR Special air-reports shall be issued every minute until such time as the peak values of the cube root of EDR fall below 0.20. 2.7 Humidity The humidity shall be reported as the relative humidity, rounded to the nearest whole per cent. Note. — The ranges and resolutions for the meteorological elements included in air-reports are shown in Table A4-3. 3. Exchange of Air-Reports 3.1 Responsibilities of the meteorological watch offices 3.1.1 The meteorological watch office shall transmit without delay the special air- reportsreceived by voice communications to WAFCs and the Centre’s designated by regional air navigation agreement for the operation of aeronautical fixed service Internet-based services. 3.1.2 The meteorological watch office shall transmit without delay special air-reports of pre- eruption volcanic activity, a volcanic eruption or volcanic ash cloud received to the associated VAACs. 3.1.3 When a special air-report is received at the meteorological watch office but the forecaster considers that the phenomenon causing the report is not expected to persist and, therefore, does not warrant issuance of a SIGMET, the special air-report shall be disseminated in the same way that SIGMET messages are disseminated in accordance with Appendix 6, 1.2.1, i.e. to meteorological watch offices, WAFCs, and other meteorological offices in accordance with regional air navigation agreement. Note: -- The template used for special air-reports which are uplinked to aircraft in flights is in Appendix 6, Table A6-1B. 3.2 Responsibilities of world area forecast centres Intentionally left blank 3.3 Supplementary dissemination of air-reports Where supplementary dissemination of air-reports is required to satisfy special aeronautical or meteorological requirements, such dissemination should be arranged and agreed between the meteorological authorities concerned. 3.4 Format of air-reports Air-reports shall be exchanged in the format in which they are received. 4. Specific provisions related to reporting Wind Shear and Volcanic Ash 4.1 Reporting of wind shear 4.1.1 When reporting aircraft observations of wind shear encountered during the climb-out and approach phases of flight, the aircraft type should be included. 4.1.2 Where wind shear conditions in the climb-out or approach phases of flight were reported or forecast but not encountered, the pilot-in-command should advise the appropriate air traffic services unit as soon as practicable unless the pilot- in-command is aware that the appropriate air traffic services unit has already been so advised by a preceding aircraft. 4.2 Post-flight reporting of volcanic activityNote. — The detailed instructions for recording and reporting volcanic activity observations are given in the PANS-ATM (Doc 4444), Appendix 1. 4.2.1 On arrival of a flight at an aerodrome, the completed report of volcanic activity shall be delivered by the operator or a flight crew member, without delay, to the aerodrome meteorological office, or if such office is not easily accessible to arriving flight crew members, the completed form shall be dealt with in accordance with local arrangements made by the meteorological authority and the operator. 4.2.2 The completed report of volcanic activity received by an aerodrome meteorological office shall be transmitted without delay to the meteorological watch office responsible for the provision of meteorological watch for the flight information region in which the volcanic activity was observed. Table A4-1. Template for the special air-report (downlink) Key: M = inclusion mandatory, part of every message; C = inclusion conditional; included whenever available. Note. — Message to be prompted by the pilot-in-command. Currently only the condition “SEV TURB” can be automated (see 2.6.3). Element as specified in Chapter 5 Detailed content Template(s) Examples Message type designator (M) Type of air-report (M) ARS ARS Aircraft identification (M) Aircraft radiotelephony call sign (M) nnnnnn VA812 DATA BLOCK 1 Latitude (M) Latitude in degrees and minutes (M) Nnnnn or Snnnn S4506 Longitude (M) Longitude in degrees and minutes (M) Wnnnnn or Ennnnn E01056 Level (M) Flight level (M) FLnnn or FLnnn to FLnnn FL330 FL280 to FL310 Time (M) Time of occurrence in hours and minutes (M) OBS AT nnnnZ OBS AT 1216ZDATA BLOCK 2 Wind direction (M) Wind direction in degrees true (M) nnn/ 262/ Wind speed (M) Wind speed in metres per second (or knots) (M) nnnMPS (or nnnKT) 040MPS (080KT) Wind quality flag (M) Wind quality flag (M) n 1 Air temperature (M) Air temperature in tenths of degrees C (M) T[M]nnn T127 TM455 Turbulence (C) Turbulence in hundredths of m2/3 s-1 and the EDRnnn/nn EDR064/08 time of occurrence of the peak value (C)1 Humidity (C) Relative humidity in per cent (C) RHnnn RH054 Element as specified in Chapter 5 Detailed content Template(s) Examples DATA BLOCK 3 Condition prompting the issuance of a special SEV TURB [EDRnnn]2 or SEV TURB EDR076 air-report (M) SEV ICE or VA CLD FL050/100 SEV MTW or TS GR3 or TS3 or HVY DS4 or HVY SS4 or VA CLD [FLnnn/nnn] or VA5 [MT nnnnnnnnnnnnnnnnnnnn] or MOD TURB [EDRnnn]2 or MOD ICE Notes. — 1. The time of occurrence to be reported in accordance with Table A4-2. 2. The turbulence to be reported in accordance with 2.6.3. 3. Obscured, embedded or widespread thunderstorms or thunderstorms in squall lines. 4. Dust storm or sandstorm. 5. Pre-eruption volcanic activity or a volcanic eruption. Table A4-2. Time of occurrence of the peak value to be reported Peak value of turbulence occurring during the one-minute period ....... minutes prior to the observation Value to be reported 0 – 1 0 1 – 2 1 2 – 3 2 . . . . . . 13 – 14 13 14 – 15 14 No timing information available 15 Table A4-3. Ranges and resolutions for the meteorological elements included in air- reportsElement as specified in Chapter 5 Range Resolution Wind direction: °true 000 – 360 1 Wind speed: MPS 00 – 125 1 KT 00 – 250 1 Wind quality flag: (index)* 0 – 1 1 Air temperature: °C –80 – +60 0.1 Turbulence: routine air-report: m2/3 s-1 0 – 2 0.01 (time of occurrence)* 0 – 15 1 Turbulence: special air-report: m2/3 s-1 0 – 2 0.01 Humidity: % 0 – 100 1 * Non-dimensional APPENDIX 5. TECHNICAL SPECIFICATIONS RELATED TO FORECASTS (See Para 6 of this CAR) 1. Criteria related to TAF 1.1 TAF format 1.1.1 TAF shall be issued in accordance with the template shown in Table A5-1 and disseminated in the TAF code form prescribed by the World Meteorological Organization (WMO). Note. — The TAF code form is contained in, Manual on Codes, WMO No. 306, Volume I.1, Part A —Alphanumeric Codes. 1.1.2 Until 4 November 2020, TAF should be disseminated in IWXXM GML form in addition to the dissemination of the TAF in accordance with 1.1.1.1.1.3 As of 5 November 2020, TAF shall be disseminated in IWXXM GML form in addition to the dissemination of the TAF in accordance with 1.1.1. Note. — The technical specifications for IWXXM are contained in the Manual on Codes (WMO-No. 306), Volume I.3, Part D — Representation Derived from Data Models. Guidance on the implementation of IWXXM is provided in the Manual on the ICAO Meteorological Information Exchange Model (IWXXM) (Doc 10003). 1.2 Inclusion of meteorological elements in TAF Note. — Guidance on operationally desirable accuracy of forecasts is given in Attachment B. 1.2.1 Surface wind In forecasting surface wind, the expected prevailing direction shall be given. When it is not possible to forecast a prevailing surface wind direction due to its expected variability, for example, during light wind conditions (less than 1.5 m/s (3 kt)) or thunderstorms, the forecast wind direction shall be indicated as variable using “VRB”. When the wind is forecast to be less than 0.5 m/s (1 kt), the forecast wind speed shall be indicated as calm. When the forecast maximum speed (gust) exceeds the forecast mean wind speed by 5 m/s (10 kt) or more, the forecast maximum wind speed shall be indicated. When a wind speed of 50 m/s (100 kt) or more is forecast, it shall be indicated to be more than 49 m/s (99 kt). 1.2.2 Visibility When the visibility is forecast to be less than 800 m, it shall be expressed in steps of 50 m; when it is forecast to be 800 m or more but less than 5 km, in steps of 100 m; 5 km or more but less than 10 km, in kilometre steps; and when it is forecast to be 10 km or more, it should be expressed as 10 km, except when conditions of CAVOK are forecast to apply. The prevailing visibility should be forecast. When visibility is forecast to vary in different directions and the prevailing visibility cannot be forecast, the lowest forecast visibility should be given. 1.2.3 Weather phenomena One or more, up to a maximum of three, of the following weather phenomena or combinations thereof, together with their characteristics and, where appropriate, intensity, shall be forecast if they are expected to occur at the aerodrome: — freezing precipitation — freezing fog — moderate or heavy precipitation (including showers thereof) — low drifting dust, sand or snow — blowing dust, sand or snow— dust storm — sandstorm — thunderstorm (with or without precipitation) — squall — funnel cloud (tornado or waterspout) — Other weather phenomena given in Appendix 3, 4.4.2.3, as agreed between the meteorological authority the appropriate ATS authority and operators concerned. The expected end of occurrence of those phenomena shall be indicated by the abbreviation “NSW”. 1.2.4 Cloud Cloud amount should be forecast using the abbreviations “FEW”, “SCT”, “BKN” or “OVC” as necessary. When it is expected that the sky will remain or become obscured and clouds cannot be forecast and information on vertical visibility is available at the aerodrome, the vertical visibility shall be forecast in the form “VV” followed by the forecast value of the vertical visibility. When several layers or masses of cloud are forecast, their amount and height of base shall be included in the following order: a) the lowest layer or mass regardless of amount, to be forecast as FEW, SCT, BKN or OVC as appropriate; b) the next layer or mass covering more than 2/8, to be forecast as SCT, BKN or OVC as appropriate; c) the next higher layer or mass covering more than 4/8, to be forecast as BKN or OVC as appropriate; and d) Cumulonimbus clouds and/or towering cumulus clouds, whenever forecast and not already included under a) to c). Cloud information should be limited to cloud of operational significance; when no cloud of operational significance is forecast, and “CAVOK” is not appropriate, the abbreviation “NSC” shall be used. 1.2.5 Temperature When forecast temperatures are included in accordance with regional air navigation agreement, the maximum and minimum temperatures expected to occur during the period of validity of the TAF should be given, together with their corresponding times of occurrence. 1.3 Use of change groups Note. ― Guidance on the use of change and time indicators in TAF is given in Table A5- 2.1.3.1 The criteria used for the inclusion of change groups in TAF or for the amendment of TAF shall be based on any of the following weather phenomena or combinations thereof being forecast to begin or end or change in intensity: — Freezing fog — freezing precipitation — moderate or heavy precipitation (including showers) — thunderstorm — dust storm — sandstorm 1.3.2 The criteria used for the inclusion of change groups in TAF or for the amendment of TAF should be based on the following: a) when the mean surface wind direction is forecast to change by 60º or more, the mean speed before and/or after the change being 5 m/s (10 kt) or more; b) when the mean surface wind speed is forecast to change by 5 m/s (10 kt) or more; c) when the variation from the mean surface wind speed (gusts) is forecast to change by 5 m/s (10 kt) or more, the mean speed before and/or after the change being 7.5 m/s (15 kt) or more; d) When the surface wind is forecast to change through values of operational significance. The threshold values should be established by the meteorological authority in consultation with the appropriate ATS authority and operators concerned, taking into account changes in the wind which would: 1) require a change in runway(s) in use; and 2) indicate that the runway tailwind and crosswind components will change through values representing the main operating limits for typical aircraft operating at the aerodrome; e) when the visibility is forecast to improve and change to or pass through one or more of the following values, or when the visibility is forecast to deteriorate and pass through one or more of the following values: 1) 150, 350, 600, 800, 1500 or 3000m; or 2) 5000m in cases where significant numbers of flights are operated in accordance with the visual flight rules. f) when any of the following weather phenomena or combinations thereof are forecast to begin or end: – low drifting dust, sand or snow – blowing dust, sand or snow– squall – funnel cloud (tornado or waterspout); g) when the height of base of the lowest layer or mass of cloud of BKN or OVC extent is forecast to lift and change to or pass through one or more of the following values, or when the height of the lowest layer or mass of cloud of BKN or OVC extent is forecast to lower and pass through one or more of the following values: 1) 30, 60, 150 or 300 m (100, 200, 500 or 1000 ft); or 2) 450 m (1500 ft) in cases where significant numbers of flights are operated in accordance with the visual flight rules; h) when the amount of a layer or mass of cloud below 450 m (1500 ft) is forecast to change: 1) from NSC, FEW or SCT to BKN or OVC; or 2) from BKN or OVC to NSC, FEW or SCT; i) when the vertical visibility is forecast to improve and change to or pass through one or more of the following values, or when the vertical visibility is forecast to deteriorate and pass through one or more of the following values: 30, 60, 150 or 300 m (100, 200, 500 or 1000 ft); and j) Any other criteria based on local aerodrome operating minima, as agreed between the meteorological authority and the operators concerned. Note. — Other criteria based on local aerodrome operating minima are to be considered in parallel with similar criteria for the issuance of SPECI developed in response to Appendix 3, 2.3.3 h). 1.3.3 When a change in any of the elements given in Para 6, 6.2.3 is required to be indicated in accordance with the criteria given in 1.3.2, the change indicators “BECMG” or “TEMPO” shall be used followed by the time period during which the change is expected to occur. The time period should be indicated as the beginning and end of the period in whole hours UTC. Only those elements for which a significant change is expected should be included following a change indicator. However, in the case of significant changes in respect of cloud, all cloud groups, including layers or masses not expected to change, should be indicated. 1.3.4 The change indicator “BECMG” and the associated time group should be used to describe changes where the meteorological conditions are expected to reach or pass through specified threshold values at a regular or irregular rate and at an unspecified time during the time period. The time period shall normally not exceed 2 hours but in any case, should not exceed 4 hours. 1.3.5 The change indicator “TEMPO” and the associated time group should be used to describe expected frequent or infrequent temporary fluctuations in the meteorological conditionswhich reach or pass specified threshold values and last for a period of less than one hour in each instance and, in the aggregate, cover less than one-half of the forecast period during which the fluctuations are expected to occur. If the temporary fluctuation is expected to last one hour or longer, the change group “BECMG” should be used in accordance with 1.3.4 or the validity period should be subdivided in accordance with 1.3.6. 1.3.6 Where one set of prevailing weather conditions is expected to change significantly and more or less completely to a different set of conditions, the period of validity shall be subdivided into self-contained periods using the abbreviation “FM” followed immediately by a four-figure time group in whole hours and minutes UTC indicating the time the change is expected to occur. The subdivided period following the abbreviation “FM” should be self-contained and all forecast conditions given before the abbreviation should be superseded by those following the abbreviation. 1.4 Use of probability groups The probability of occurrence of an alternative value of a forecast element or elements should be indicated, as necessary, by use of the abbreviation “PROB” followed by the probability in tens of per cent and the time period during which the alternative value(s) is (are) expected to apply. The probability information shall be placed after the element or elements forecast and be followed by the alternative value of the element or elements. The probability of a forecast of temporary fluctuations in meteorological conditions should be indicated, as necessary, by use of the abbreviation “PROB” followed by the probability in tens of per cent, placed before the change indicator “TEMPO” and associated time group. A probability of an alternative value or change of less than 30 per cent should not be considered sufficiently significant to be indicated. A probability of an alternative value or change of 50 per cent or more, for aviation purposes, should not be considered a probability but instead should be indicated, as necessary, by use of the change indicators “BECMG” or “TEMPO” or by subdivision of the validity period using the abbreviation “FM”. The probability group should not be used to qualify the change indicator “BECMG” nor the time indicator “FM”. 1.5 Number of change and probability groups The number of change and probability groups should be kept to a minimum and should not normally exceed five groups. 1.6 Dissemination of TAF TAF and amendments there to shall be disseminated to international OPMET databanks and the centres designated by regional air navigation agreement for the operation of aeronautical fixed service Internet-based services, in accordance with regional air navigation agreement. 2. Criteria related to Trend Forecasts2.1 Format of trend forecasts Trend forecasts shall be issued in accordance with the templates shown in Appendix 3, Tables A3-1 and A3-2. The units and scales used in the trend forecast shall be the same as those used in the report to which it is appended. Note. — Examples of trend forecasts are given in Appendix 3. 2.2 Inclusion of meteorological elements in trend forecasts 2.2.1 General provisions The trend forecast shall indicate significant changes in respect of one or more of the elements: surface wind, visibility, weather and clouds. Only those elements shall be included for which a significant change is expected. However, in the case of significant changes in respect of cloud, all cloud groups, including layers or masses not expected to change, shall be indicated. In the case of a significant change in visibility, the phenomenon causing the reduction of visibility shall also be indicated. When no change is expected to occur, this shall be indicated by the term “NOSIG”. 2.2.2 Surface wind The trend forecast shall indicate changes in the surface wind which involve: a) a change in the mean wind direction of 60° or more, the mean speed before and/or after the change being 5 m/s (10 kt) or more; b) a change in mean wind speed of 5 m/s (10 kt) or more; and c) Changes in the wind through values of operational significance. The threshold values shall be established by the meteorological authority in consultation with the appropriate ATS authority and operators concerned, taking into account changes in the wind which would: 1) require a change in runway(s) in use; and 2) Indicate that the runway tailwind and crosswind components will change through values representing the main operating limits for typical aircraft operating at the aerodrome. 2.2.3 Visibility When the visibility is expected to improve and change to or pass through one or more of the following values, or when the visibility is expected to deteriorate and pass through one or more of the following values: 150, 350, 600, 800, 1500or 3000 m, the trend forecast shall indicate the change. When significant numbers of flights are conducted in accordance withthe visual flight rules, the forecast shall additionally indicate changes to or passing through 5000 m. Note. — In trend forecasts appended to local routine and special reports, visibility refers to the forecast visibility along the runway(s); in trend forecasts appended to METAR and SPECI, visibility refers to the forecast prevailing visibility. 2.2.4 Weather phenomena 2.2.4.1 The trend forecast shall indicate the expected onset, cessation or change in intensity of one or more of the following weather phenomena or combinations thereof: — freezing precipitation — moderate or heavy precipitation (including showers) — thunderstorm (with precipitation) — dust storm — sandstorm — Other weather phenomena given in Appendix 3, 4.4.2.3, as agreed by the meteorological authority, the appropriate ATS authority and operators concerned. 2.2.4.2 The trend forecast shall indicate the expected onset or cessation of one or more of the following weather phenomena or combinations thereof: — freezing fog — low drifting dust, sand or snow — blowing dust, sand or snow — thunderstorm (without precipitation) — squall — Funnel cloud (tornado or waterspout). 2.2.4.3 The total number of phenomena reported in 2.2.4.1 and 2.2.4.2 shall not exceed three. 2.2.4.4 The expected end of occurrence of the weather phenomena shall be indicated by the abbreviation “NSW”. 2.2.5 Clouds When the height of the base of a cloud layer of BKN or OVC extent is expected to lift and change to or pass through one or more of the following values, or when the height of the base of a cloud layer of BKN or OVC extent is expected to lower and pass through one or more of the following values: 30, 60, 150, 300 and 450 m (100, 200, 500, 1000 and 1500 ft), the trend forecast shall indicate the change. When the height of the base of a cloud layeris below or is expected to fall below or rise above 450 m (1500 ft), the trend forecast shall also indicate changes in cloud amount from FEW, or SCT increasing to BKN or OVC, or changes from BKN or OVC decreasing to FEW or SCT. When no cloud of operational significance is forecast and “CAVOK” is not appropriate, the abbreviation “NSC” shall be used. 2.2.6 Vertical stability When the sky is expected to remain or become obscured and vertical visibility observations are available at the aerodrome, and the vertical visibility is forecast to improve and change to or pass through one or more of the following values, or when the vertical visibility is forecast to deteriorate and pass through one or more of the following values: 30, 60, 150 or 300 m (100, 200, 500 or 1000 ft), the trend forecast shall indicate the change. 2.2.7 Additional criteria Criteria for the indication of changes based on local aerodrome operating minima, additional to those specified in 2.2.2 to 2.2.6, shall be used as agreed between the meteorological authority and the operator concerned. 2.3 Use of change groups Note. ― Guidance on the use of change indicators in trend forecasts is given in Appendix3, Table A3-3. 2.3.1 When a change is expected to occur, the trend forecast shall begin with one of the change indicators “BECMG” or “TEMPO”. 2.3.2 The change indicator “BECMG” shall be used to describe forecast changes where the meteorological conditions are expected to reach or pass through specified values at a regular or irregular rate. The period during which, or the time at which, the change is forecast to occur shall be indicated, using the abbreviations “FM”, “TL” or “AT”, as appropriate, each followed by a time group in hours and minutes. When the change is forecast to begin and end wholly within the trend forecast period, the beginning and end of the change shall be indicated by using the abbreviations “FM” and “TL”, respectively, with their associated time groups. When the change is forecast to commence at the beginning of the trend forecast period but be completed before the end of that period, the abbreviation “FM” and its associated time group shall be omitted and only “TL” and its associated time group shall be used. When the change is forecast to begin during the trend forecast period and be completed at the end of that period, the abbreviation “TL” and its associated time group shall be omitted and only “FM” and its associated time group shall be used. When the change is forecast to occur at a specified time during the trend forecast period, the abbreviation “AT” followed by its associated time group shall be used. When the change is forecast to commence at the beginning of the trend forecast period and be completed by the end of that period or when the change is forecast to occur within the trend forecast periodbut the time is uncertain, the abbreviations “FM”, “TL” or “AT” and their associated time groups shall be omitted and the change indicator “BECMG” shall be used alone. 2.3.3 The change indicator “TEMPO” shall be used to describe forecast temporary fluctuations in the meteorological conditions which reach or pass specified values and last for a period of less than one hour in each instance and, in the aggregate, cover less than one-half of the period during which the fluctuations are forecast to occur. The period during which the temporary fluctuations are forecast to occur shall be indicated, using the abbreviations “FM” and/or “TL”, as appropriate, each followed by a time group in hours and minutes. When the period of temporary fluctuations in the meteorological conditions is forecast to begin and end wholly within the trend forecast period, the beginning and end of the period of temporary fluctuations shall be indicated by using the abbreviations “FM” and “TL”, respectively, with their associated time groups. When the period of temporary fluctuations is forecast to commence at the beginning of the trend forecast period but cease before the end of that period, the abbreviation “FM” and its associated time group shall be omitted and only “TL” and its associated time group shall be used. When the period of temporary fluctuations is forecast to begin during the trend forecast period and cease by the end of that period, the abbreviation “TL” and its associated time group shall be omitted and only “FM” and its associated time group shall be used. When the period of temporary fluctuations is forecast to commence at the beginning of the trend forecast period and cease by the end of that period, both abbreviations “FM” and “TL” and their associated time groups shall be omitted and the change indicator “TEMPO” shall be used alone. 2.4 Use of the probability indicator The indicator “PROB” shall not be used in trend forecasts. 3. Criteria related to forecast for Take-off 3.1 Format of forecasts for take-off The format of the forecast should be as agreed between the meteorological authority and the operator concerned. The order of the elements and the terminology, units and scales used in forecasts for take-off should be the same as those used in reports for the same aerodrome. 3.2 Amendments to forecasts for take-off The criteria for the issuance of amendments for forecasts for take-off for surface wind direction and speed, temperature and pressure and any other elements agreed locally should be agreed between the meteorological authority and the operators concerned. The criteriashould be consistent with the corresponding criteria for special reports established for the aerodrome in accordance with Appendix 3, 2.3.1. 4. Criteria related to Area Forecast for Low-level flights 4.1 Format and content of GAMET area forecasts Intentionally left blank 4.2 Amendments to GAMET area forecasts Intentionally left blank 4.3 Exchange of area forecasts for low-level flights 4.3.1 When chart form is used for area forecasts for low-level flights, the forecast of upper wind and upper-air temperature shall be issued for points separated by no more than 500 km (300 NM) and for at least the following altitudes: 600, 1 500 and 3 000 m (2 000, 5 000 and 10 000 ft), and 4 500 m (15 000 ft) in mountainous areas. 4.3.2 When chart form is used for area forecasts for low-level flights, the forecast of SIGWX phenomena shall be issued as low-level SIGWX forecast for flight levels up to 100 (or up to flight level 150 in mountainous areas, or higher, where necessary). Low-level SIGWX forecasts shall include the following items: a) the phenomena warranting the issuance of a SIGMET as given in Appendix 6 and which are expected to affect low-level flights; and b) the elements in area forecasts for low-level flights as given in Table A5-3 except elements concerning: 1) upper wind and upper-air temperature; and 2) Forecast QNH. 4.4 Exchange and dissemination of area forecasts for low-level flights 4.4.1 Area forecasts for low-level flights prepared in support of the issuance of AIRMET information shall be exchanged between aerodrome meteorological offices and/or meteorological watch offices responsible for the issuance of flight documentation for low- level flights in the flight information regions concerned. 4.4.2 Area forecasts for low-level flights, in support of international air navigation, prepared in accordance with regional air navigation agreement and in support of the issuance of AIRMET information should be disseminated to the aeronautical fixed service Internet- based Services.Table A5-1. Template for TAF Key: M = inclusion mandatory, part of every message; C = inclusion conditional, dependent on meteorological conditions or method of observation; O = inclusion optional. Note 1.— The ranges and resolutions for the numerical elements included in TAF are shown in Table A5-4 of this appendix. Note 2.— The explanations for the abbreviations can be found in the Procedures for Air Navigation Services — ICAO Abbreviations and Codes (PANS-ABC, Doc 8400). Element as specified in Chapter 6 Detailed content Template(s) Examples Identification of the type Type of forecast (M) TAF or TAF AMD or TAF COR TAF of forecast (M) TAF AMD Location indicator (M) ICAO location indicator (M) nnnn YUDO1 Time of issue of forecast Day and time of issue of the nnnnnnZ 160000Z (M) forecast in UTC (M) Identification of a Missing forecast identifier (C) NIL NIL missing forecast (C) END OF TAF IF THE FORECAST IS MISSING.Element as specified in Chapter 6 Detailed content Template(s) Examples Days and period of Days and period of the validity of nnnn/nnnn 0812/0918 validity of forecast (M) the forecast in UTC (M) Identification of a Cancelled forecast identifier (C) CNL CNL cancelled forecast (C) END OF TAF IF THE FORECAST IS CANCELLED. Surface wind (M) Wind direction (M) nnn or VRB2 24004MPS; VRB01MPS (24008KT); (VRB02KT) Wind speed (M) [P]nn[n] 19005MPS Significant speed variations (C)3 G[P]nn[n] (19010KT) Units of measurement (M) MPS (or KT) 00000MPS (00000KT) 140P49MPS (140P99KT) 12003G09MPS (12006G18KT) 24008G14MPS (24016G28KT) Visibility (M) Prevailing visibility (M) nnnn C 0350 CAVOK A 7000 V 9000 O 9999 K Weather (C)4, 5 Intensity of weather – or + — RA HZ phenomena (C)6 +TSRA FG –FZDZ PRFG Characteristics and type of weather DZ or RA or FG or BR or phenomena (C)7 SN or SG or SA or DU or +TSRASN PL or DS or HZ or FU or SS or FZDZ or VA or SQ or SNRA FG FZRA or SHGR or PO or FC or SHGS or SHRA or TS or SHSN or TSGR or BCFG or TSGS or TSRA or BLDU or TSSN BLSA or BLSN or DRDU or DRSA or DRSN or FZFG or MIFG or PRFG Cloud (M)8 Cloud amount and FEWnnn or VVnnn or NSC FEW010 VV005 height of base or SCTnnn or VV/// OVC020 VV/// vertical visibility (M) BKNnnn or NSC OVCnnn SCT005 BKN012 SCT008 BKN025CB Cloud type (C)4 CB or TCU — Temperature (O)9 Name of the element (M) TX TX25/1013Z TN09/1005Z TX05/2112Z TNM02/2103Z Maximum temperature (M) [M]nn/ Day and time of occurrence of the nnnnZ maximum temperature (M) Name of the element (M) TN Minimum temperature (M) [M]nn/ Day and time of occurrence of the nnnnZ minimum temperature (M)Expected significant Change or probability indicator (M) PROB30 [TEMPO] or PROB40 [TEMPO] or TEMPO 0815/0818 25017G25MPS changes to one or more BECMG or TEMPO or FM (TEMPO 0815/0818 25034G50KT) of the above elements Period of occurrence or change (M) nnnn/nnnn or nnnnnn11 during the period of TEMPO 2212/2214 17006G13MPS 1000 validity (C)4, 10 Wind (C)4 nnn[P]nn[n][G[P]nn[n]]MPS or VRBnnMPS TSRA SCT010CB BKN020 (or nnn[P]nn[G[P]nn]KT or VRBnnKT) (TEMPO 2212/2214 17012G26KT 1000 Prevailing visibility (C)4 nnnn C TSRA SCT010CB BKN020) A Weather phenomenon: – or + — NSW V BECMG 3010/3011 00000MPS 2400 intensity (C)6 O OVC010 Weather phenomenon: DZ or RA or FG or K (BECMG 3010/3011 00000KT 2400 characteristics and type (C)4, 7 SN or SG or BR or SA or OVC010) PL or DS or DU or HZ or SS or FU or VA or PROB30 1412/1414 0800 FG FZDZ or SQ or PO or BECMG 1412/1414 RA FZRA or FC or TS or TEMPO 2503/2504 FZRA SHGR or BCFG or TEMPO 0612/0615 BLSN SHGS or BLDU or PROB40 TEMPO 2923/3001 0500 FG SHRA or BLSA or SHSN or BLSN or TSGR or DRDU or TSGS or DRSA or TSRA or DRSN or TSSN FZFG or MIFG or PRFG Cloud amount and height of base FEWnnn or VVnnn or NSC FM051230 15015KMH 9999 BKN020 or vertical visibility (C)4 SCTnnn or VV/// (FM051230 15008KT 9999 BKN020) BKNnnn or OVCnnn BECMG 1618/1620 8000 NSW NSC BECMG 2306/2308 SCT015CB BKN020 Cloud type (C)4 CB or TCU — Notes. — 1. Fictitious location. 2. To be used in accordance with 1.2.1. 3. To be included in accordance with 1.2.1. 4. To be included whenever applicable. 5. One or more, up to a maximum of three, groups in accordance with 1.2.3. 6. To be included whenever applicable in accordance with 1.2.3. No qualifier for moderate intensity. 7. Weather phenomena to be included in accordance with 1.2.3. 8. Up to four cloud layers in accordance with 1.2.4. 9. To be included in accordance with 1.2.5, consisting of up to a maximum of four temperatures (two maximum temperatures and two minimum temperatures). 10. To be included in accordance with 1.3, 1.4 and 1.5. 11. To be used with FM only.Table A5-2. Use of change and time indicators in TAF Change or time indicator Time period Meaning FM ndndnhnhnmnm used to indicate a significant change in most weather elements occurring at ndnd day, nhnh hours and nmnm minutes (UTC); all the elements given before “FM” are to be included following “FM” (i.e. they are all superseded by those following the abbreviation) BECMG nd1nd1nh1nh1/nd2nd2nh2nh2 the change is forecast to commence at nd1nd1 day and nh1nh1 hours (UTC) and be completed by nd2nd2 day and nh2nh2 hours (UTC); only those elements for which a change is forecast are to be given following “BECMG”; the time period nd1nd1nh1nh1/nd2nd2nh2nh2 should normally be less than 2 hours and in any case should not exceed 4 hours TEMPO nd1nd1nh1nh1/nd2nd2nh2nh2 temporary fluctuations are forecast to commence at nd1nd1 day and nh1nh1 hours (UTC) and cease by nd2nd2 day and nh2nh2 hours (UTC); only those elements for which fluctuations are forecast are to be given following “TEMPO”; temporary fluctuations should not last more than one hour in each instance, and in the aggregate, cover less than half of the period nd1nd1nh1nh1/nd2nd2nh2nh2 PROBnn — nd1nd1nh1nh1/nd2nd2nh2nh2 probability of occurrence (in %) of an alternative value — of a forecast element or elements; TEMPO nd1nd1nh1nh1/nd2nd2nh2nh2 nn = 30 or nn = 40 only; probability of occurrence of temporary fluctuations to be placed after the element(s) concerned Table A5-3. Template for GAMET Key: M = inclusion mandatory, part of every message; C = inclusion conditional, dependent on meteorological conditions; O = inclusion optional; = = a double line indicates that the text following it should be placed on the subsequent line. Element Detailed content Template(s) Examples Location indicator of ICAO location indicator of the nnnn YUCC1 FIR/CTA (M) ATS unit serving the FIR or CTA to which the GAMET refers (M) Identification (M) Message identification (M) GAMET GAMET Validity period (M) Day-time groups indicating VALID nnnnnn/nnnnnn VALID 220600/221200 the period of validity in UTC (M) Location indicator of Location indicator of nnnn– YUDO–1 aerodrome meteorological aerodrome meteorological office or meteorological watch office or meteorological watch office (M) office originating the message with a separating hyphen (M) Name of the FIR/CTA or part Location indicator and name nnnn nnnnnnnnnn FIR[/n] [BLW FLnnn] YUCC AMSWELL FIR/2 BLW FL120 thereof (M) of the FIR/CTA, or part or thereof for which the GAMET nnnn nnnnnnnnnn CTA[/n] [BLW FLnnn] YUCC AMSWELL FIR is issued (M)Template(s) Identifier and Element Detailed content time Location Content Examples Indicator for the beginning of Indicator to identify the Section I (M) beginning of Section I (M) SECN I SECN I Surface wind (C) Widespread surface wind SFC WIND: [N OF Nnn or Snn] nnn/[n]nnMPS SFC WIND: 10/12 310/16MPS exceeding 15 m/s (30 kt) [nn/nn] or (or nnn/[n]nnKT) [S OF Nnn or Snn] SFC WIND: E OF W110 050/40KT or Surface visibility (C) Widespread surface visibility SFC VIS: [W OF Wnnn or nnnnM FG or BR or SFC VIS: 06/08 N OF N51 3000M BR below 5 000 m including the [nn/nn] Ennn] or SA or DU or weather phenomena causing [E OF Wnnn or HZ or FU or the reduction in visibility Ennn] or VA or PO or [nnnnnnnnnn]2 DS or SS or DZ or RA or SN or SG or FC or GR or GS or PL or SQ Significant weather (C) Significant weather conditions SIGWX: ISOL TS or SIGWX: 11/12 ISOL TS encompassing thunderstorms, [nn/nn] OCNL TS or heavy sandstorm and FRQ TS or SIGWX: 12/14 S OF N35 HVY SS duststorm, and volcanic ash OBSC TS or EMBD TS or HVY DS or HVY SS or SQL TS or ISOL TSGR or OCNL TSGR or FRQ TSGR or OBSC TSGR or EMBD TSGR or SQL TSGR or VA Mountain obscuration (C) Mountain obscuration MT OBSC: nnnnnnnnnn2 MT OBSC: S OF N48 MT PASSES [nn/nn] Cloud (C) Widespread areas of broken SIG CLD: BKN or OVC SIG CLD: 06/09 N OF N51 OVC or overcast cloud with height [nn/nn] [n]nnn/[n]nnnM 800/1100FT AGL 10/12 ISOL TCU of base less than 300 m (or [n]nnn/[n]nnnFT) 1200/8000FT AGL (1 000 ft) above ground level AGL or AMSL (AGL) or above mean sea ISOL or OCNL or level (AMSL) and/or any FRQ or OBSC or occurrence of EMBD cumulonimbus (CB) or CB3 or TCU3 towering cumulus (TCU) [n]nnn/[n]nnnM clouds (or [n]nnn/[n]nnnFT) AGL or AMSL Icing (C) Icing (except for that ICE: [nn/nn] MOD FLnnn/nnn or ICE: MOD FL050/080 occurring in convective clouds MOD ABV FLnnn or and for severe icing for which SEV FLnnn/nnn or a SIGMET message has SEV ABV FLnnn already been issued) Turbulence (C) Turbulence (except for that TURB: [nn/nn] MOD FLnnn/nnn or TURB: MOD ABV FL090 occurring in convective clouds MOD ABV FLnnn or and for severe turbulence for SEV FLnnn/nnn or which a SIGMET message SEV ABV FLnnn has already been issued) Mountain wave (C) Mountain wave (except for MTW: [nn/nn] MOD FLnnn/nnn or MTW: N OF N63 MOD ABV FL080 severe mountain wave for MOD ABV FLnnn or which a SIGMET message SEV FLnnn/nnn or has already been issued) SEV ABV FLnnnTemplate(s) Identifier and Element Detailed content time Location Content Examples SIGMET (C) SIGMET messages SIGMET — [n][n]n4 SIGMET APPLICABLE: 3, A5, B06 applicable to the FIR/CTA APPLICABLE: concerned or a sub-area thereof, for which the area forecast is valid or HAZARDOUS WX NIL (C)5 HAZARDOUS WX NIL HAZARDOUS WX NIL Indicator for the beginning Indicator to identify the of Section II (M) beginning of Section II (M) SECN II SECN II Pressure centres and fronts Pressure centres and fronts PSYS: [nn] Nnnnn or Snnnn L [n]nnnHPA or H PSYS: 06 N5130 E01000 L 1004HPA (M) and their expected Wnnnnn or [n]nnnHPA MOV NE 25KT WKN movements and Ennnnn or or developments Nnnnn or Snnnn FRONT or NIL Wnnnnn or Ennnnn TO Nnnnn or Snnnn Wnnnnn or Ennnnn — MOV N or MOV NE or MOV E or MOV SE or MOV S or MOV SW or MOV W or MOV NW nnKMH (or nnKT) WKN or NC or INTSF Upper winds and Upper wind and upper-air WIND/T: Nnnnn or Snnnn [n]nnnM WIND/T: 2000FT N5500 W01000 temperatures (M) temperature for at least the Wnnnnn or (or [n]nnnFT) 270/18MPS PS03 5000FT N5500 following altitudes: 600, 1 500 Ennnnn nnn/[n]nnMPS W01000 250/20MPS MS02 10000FT and 3 000 m (2 000, 5 000 (or nnn/[n]nnKT) N5500 W01000 240/22MPS MS11 and 10 000 ft) or PSnn or MSnn Cloud (M) Cloud information not CLD: [nn/nn] [N OF Nnn or Snn] FEW or SCT or CLD: BKN SC 2500/8000FT AGL included in Section I giving or BKN or OVC type, height of base and top [S OF Nnn or Snn] ST or SC or CU or CLD: NIL above ground level (AGL) or or AS or AC or NS above mean sea level (AMSL) [W OF Wnnn or [n]nnn/[n]nnnM Ennn] or (or [n]nnn/[n]nnnFT) [E OF Wnnn or AGL or AMSL or NIL Ennn] Freezing level (M) Height indication of 0°C FZLVL: or [ABV] [n]nnnFT FZLVL: 3000FT AGL level(s) above ground level [nnnnnnnnnn]2 AGL or AMSL (AGL) or above mean sea level (AMSL), if lower than the top of the airspace for which the forecast is supplied Forecast QNH (M) Forecast lowest QNH during MNM QNH: [n]nnnHPA MNM QNH: 1004HPA the period of validity Sea-surface temperature and Sea-surface temperature and SEA: Tnn HGT [n]nM SEA: T15 HGT 5M state of the sea (O) state of the sea if required by regional air navigation agreement Volcanic eruptions (M) Name of volcano VA: nnnnnnnnnn or NIL VA: ETNA VA: NIL Notes. — 1. Fictitious location. 2. Free text describing well-known geographical locations should be kept to a minimum.3. The location of the CB and/or TCU should be specified in addition to any widespread areas of broken or overcast cloud as given in the example. 4. List as necessary, with comma separating. 5. When no elements are included in Section I. Table A5-4. Ranges and resolutions for the numerical elements included in TAF Element as specified in Chapter 6 Range Resolution Wind direction: ° true 000 – 360 10 Wind speed: MPS 00 – 99* 1 KT 00 – 199* 1 Visibility: M 0000 – 0750 50 M 0800 – 4 900 100 M 5 000 – 9 000 1 000 M 10 000 – 0 (fixed value: 9 999) Vertical visibility: 30’s M (100’s FT) 000 – 020 1 Cloud: height of cloud base: 30’s M (100’s FT) 000 – 100 1 Air temperature (maximum and minimum): °C –80 – +60 1 * There is no aeronautical requirement to report surface wind speeds of 50 m/s (100 kt) or more; however, provision has been made for reporting wind speeds up to 99 m/s (199 kt) for non-aeronautical purposes, as necessary.Example A5-1. TAF TAF for YUDO (Donlon/International) *: TAF YUDO 151800Z 1600/1618 13005MPS 9000 BKN020 BECMG 1606/1608 SCT015CB BKN020 TEMPO 1608/1612 17006G12MPS 1000 TSRA SCT010CB BKN020 FM161230 15004MPS 9999 BKN020 Meaning of the forecast: TAF for Donlon/International* issued on the 15th of the month at 1800 UTC valid from 0000 UTC to 1800 UTC on the 16th of the month; surface wind direction 130 degrees; wind speed 5 metres per second; visibility 9 kilometres, broken cloud at 600 metres; becoming between 0600 UTC and 0800 UTC on the 16th of the month, scattered cumulonimbus cloud at 450 metres and broken cloud at 600 metres; temporarily between 0800 UTC and 1200 UTC on the 16th of the month surface wind direction 170 degrees; wind speed 6 metres per second gusting to 12 metres per second; visibility 1 000 metres in a thunderstorm with moderate rain, scattered cumulonimbus cloud at 300 metres and broken cloud at 600 metres; from 1230 UTC on the 16th of the month surface wind direction 150 degrees; wind speed 4 metres per second; visibility 10 kilometres or more; and broken cloud at 600 metres. Fictitious location * Note. — In this example, the primary units “metre per second” and “metre” were used for wind speed and height of cloud base, respectively. However, in accordance with Annex 5, the corresponding non-SI alternative units “knot” and “foot” may be used instead.Example A5-2. Cancellation of TAF Cancellation of TAF for YUDO (Donlon/International) *: TAF AMD YUDO 161500Z 1600/1618 CNL Meaning of the forecast: Amended TAF for Donlon/International* issued on the 16th of the month at 1500 UTC cancelling the previously issued TAF valid from 0000 UTC to 1800 UTC on the 16th of the month. Fictitious location * Example A5-3. GAMET area forecast YUCC GAMET VALID 220600/221200 YUDO – YUCC AMSWELL FIR/2 BLW FL120 SECN I SFC WIND: 10/12 310/16MPS SFC VIS: 06/08 N OF N51 3000M BR SIGWX: 11/12 ISOL TS SIG CLD: 06/09 N OF N51 OVC 800/1100FT AGL 10/12 ISOL TCU 1200/8000FT AGL ICE: MOD FL050/080 TURB: MOD ABV FL090 SIGMET APPLICABLE: 3, 5 SECN II PSYS: 06 N5130 E01000 L 1004HPA MOV NE 25KT WKN WIND/T: 2000FT N5500 W01000 270/18MPS PS03 5000FT N5500 W01000 250/20MPS MS02 10000FT N5500 W01000 240/22MPS MS11 CLD: BKN SC 2500/8000FT AGL FZLVL: 3000FT AGL MNM QNH: 1004HPA SEA: T15 HGT 5M VA: NILMeaning: An area forecast for low-level flights (GAMET) issued for sub- area two of the Amswell* flight information region (identified by YUCC Amswell area control centre) for below flight level 120 by the Donlon/International* aerodrome meteorological office (YUDO); the message is valid from 0600 UTC to 1200 UTC on the 22nd of the month. Section I: surface wind speed and direction: between 1000 UTC and 1200 UTC surface wind direction 310 degrees; wind speed 16 metres per second; surface visibility: between 0600 UTC and 0800 UTC north of 51 degrees north 3 000 metres (due to mist); significant weather phenomena: between 1100 UTC and 1200 UTC isolated thunderstorms without hail; significant clouds: between 0600 UTC and 0900 UTC north of 51 degrees north overcast base 800, top 1 100 feet above ground level; between 1000 UTC and 1200 UTC isolated towering cumulus base 1 200, top 8 000 feet above ground level; icing: moderate between flight level 050 and 080; turbulence: moderate above flight level 090 (at least up to flight level 120); SIGMET messages: 3 and 5 applicable to the validity period and sub-area concerned. Section II: pressure systems: at 0600 UTC low pressure of 1 004 hectopascals at 51.5 degrees north 10.0 degrees east, expected to move north-eastwards at 25 knots and to weaken; winds and temperatures: at 2 000 feet above ground level at 55 degrees north 10 degrees west wind direction 270 degrees, wind speed 18 metres per second, temperature plus 3 degrees Celsius; at 5 000 feet above ground level at 55 degrees north 10 degrees west wind direction 250 degrees, wind speed 20 metres per second, temperature minus 2 degrees Celsius; at 10 000 feet above ground level at 55 degrees north 10 degrees west wind direction 240 degrees, wind speed 22 metres per second, temperature minus 11 degrees Celsius; clouds: broken stratocumulus, base 2 500 feet, top 8 000 feet above ground level; freezing level: 3 000 feet above ground level; minimum QNH: 1 004 hectopascals; sea: surface temperature 15 degrees Celsius; and state of the sea 5 metres; volcanic ash: nil. * Fictitious locationAPPENDIX 6. TECHNICAL SPECIFICATIONS RELATED TO SIGMET AND AIRMET INFORMATION, AERODROME WARNINGS AND WIND SHEAR WARNINGS AND ALERTS (See Para 7 of this CAR) Note. — Data type designators to be used in abbreviated headings for SIGMET, AIRMET, tropical cyclone and volcanic ash advisory messages are given in Manual on the Global Telecommunication System (WMO-No. 386). 1. Specifications related to SIGMET information 1.1 Format of SIGMET messages 1.1.1 The content and order of elements in a SIGMET message shall be in accordance with the template shown in Table A6-1A. 1.1.2 Messages containing SIGMET information shall be identified as: “SIGMET”. 1.1.3 The sequence number referred to in the template in Table A6-1A shall correspond with the number of SIGMET messages issued for the flight information region (FIR) since 0001 UTC on the day concerned. The meteorological watch offices whose area of responsibility encompasses more than one FIR and/or control area (CTA) shall issue separate SIGMET messages for each FIR and/or CTA within their area of responsibility. 1.1.4 In accordance with the template in Table A6-1A, only one of the following phenomena shall be included in a SIGMET message, using the abbreviations as indicated below: At cruising levels (irrespective of altitude): thunderstorm — obscured OBSC TS — embedded EMBD TS — frequent FRQ TS — squall line SQL TS — obscured with hail OBSC TSGR — embedded with hail EMBD TSGR — frequent, with hail FRQ TSGR — squall line with hail SQL TSGR tropical cyclone — tropical cyclone with 10-minute mean TC (+ cyclone name) surface wind speed of 17 m/s (34 kt) or more turbulence — severe turbulence SEV TURB icing— severe icing SEV ICE — severe icing due to SEV ICE (FZRA) freezing rain mountain wave — severe mountain wave SEV MTW duststorm — heavy duststorm HVY DS sandstorm — heavy sandstorm HVY SS volcanic ash — volcanic ash VA (+ volcano name, if known) radioactive cloud RDOACT CLD 1.1.5 Until SIGMET information shall not contain unnecessary descriptive material. In describing the weather phenomena for which the SIGMET is issued, no descriptive material additional to that given in 1.1.4 shall be included. SIGMET information concerning thunderstorms or a tropical cyclone shall not include references to associated turbulence and icing. 1.1.6 Until 4 November 20202, SIGMET information should be disseminated in IWXXM GML form, in addition to the dissemination of SIGMET information in accordance with 1.1.1. 1.1.7 As of 5 November 2020, SIGMET information shall be disseminate in IWXXM GML form in addition to the dissemination of SIGMET information in accordance with 1.1.1. Note. — The technical specifications for IWXXM are contained in the Manual on Codes (WMO-No. 306), Volume I.3, and Part D— Representation Derived from Data Models. Guidance on the implementation of IWXXM is provided in the Manual on the ICAO Meteorological Information Exchange Model (IWXXM) (Doc 10003). 1.1.8 SIGMET, when issued in graphical format, should be as specified in Appendix 1, including the use of applicable symbols and/or abbreviations. 1.2 Dissemination of SIGMET messages 1.2.1 SIGMET messages shall be disseminated to meteorological watch offices, WAFCs and to other meteorological offices in accordance with regional air navigation agreement. SIGMET messages for volcanic ash shall also be disseminated to VAACs. 1.2.2 SIGMET messages shall be disseminated to international OPMET databanks and the centers designated by regional air navigation agreement for the operation of aeronautical fixed service satellite distribution systems, in accordance with regional air navigation agreement.2. Specification related to AIRMET Information 2.1 Format of AIRMET messages Intentionally left blank 2.2 Dissemination of AIRMET messages Intentionally left blank 3. SPECIFICATIONS RELATED TO SPECIAL AIR-REPORTS Intentionally left blank 3.1 Intentionally left blank 3.2 Intentionally left blank 4. Detailed criteria related to SIGMET, AIRMET messages and Special Air- Reports (Uplink) 4.1 Identification of the flight information region (FIR) In cases where the airspace is divided into a flight information region (FIR) and an upper flight information region (UIR), the SIGMET should be identified by the location indicator of the air traffic services unit serving the FIR. Note. — The SIGMET message applies to the whole airspace within the lateral limits of the FIR, i.e. to the FIR and to the UIR. The particular areas and/or flight levels affected by the meteorological phenomena causing the issuance of the SIGMET are given in the text of the message. 4.2 Criteria related to phenomena included in SIGMET, AIRMET messages and special air-reports (uplink) 4.2.1 An area of thunderstorms and cumulonimbus clouds should be considered: a) obscured (OBSC) if it is obscured by haze or smoke or cannot be readily seen due to darkness; and b) Embedded (EMBD) if it is embedded within cloud layers and cannot be readily recognized. c) isolated (ISOL) if it consists of individual features which affect, or are forecast to affect, an area with a maximum spatial coverage less than 50 per cent of the area concerned (at a fixed time or during the period of validity); andd) occasional (OCNL) if it consists of well-separated features which affect, or are forecast to affect, an area with a maximum spatial coverage between 50 and 75 per cent of the area concerned (at a fixed time or during the period of validity). 4.2.2 An area of thunderstorms should be considered frequent (FRQ) if within that area there is little or no separation between adjacent thunderstorms with a maximum spatial coverage greater than 75 per cent of the area affected, or forecast to be affected, by the phenomenon (at a fixed time or during the period of validity). 4.2.3 Squall line (SQL) should indicate a thunderstorm along a line with little or no space between individual clouds. 4.2.4 Hail (GR) should be used as a further description of the thunderstorm, as necessary. 4.2.5 Severe and moderate turbulence (TURB) should refer only to: low-level turbulence associated with strong surface winds; rotor streaming; or turbulence whether in cloud or not in cloud (CAT). Turbulence should not be used in connection with convective clouds. 4.2.6 Turbulence shall be considered: a) severe whenever the peak value of EDR equals or exceeds 0.45; and b) Moderate whenever the peak value of EDR is equals to or above 0.20 and below 0.4. 4.2.7 Severe and moderate icing (ICE) should refer to icing in other than convective clouds. Freezing rain (FZRA) should refer to severe icing conditions caused by freezing rain. 4.2.8 A mountain wave (MTW) should be considered: a) severe whenever an accompanying downdraft of 3.0 m/s (600 ft/min) or more and/or severe turbulence is observed or forecast; and b) Moderate whenever an accompanying downdraft of 1.75–3.0 m/s (350– 600 ft./min) and/or moderate turbulence is observed or forecast. 4.2.9 Sandstorm/dust storm should be considered: a) heavy whenever the visibility is below 200 m and the sky is obscured; and b) moderate whenever the visibility is: 1) below 200 m and the sky is not obscured; or 2) Between 200 m and 600 m. 5. Specifications related to Aerodrome Warnings 5.1 Format and dissemination of aerodrome warnings 5.1.1 When The aerodrome warnings shall be issued in accordance with the template in Table A6-2 where required by operators or aerodrome services, and shall be disseminated inaccordance with local arrangements to those concerned. 5.1.2 The sequence number referred to in the template in Table A6-2 shall correspond with the number of aerodrome warnings issued for the aerodrome since 0001 UTC on the day concerned. 5.1.3 In accordance with the template in Table A6-2, aerodrome warnings should relate to the occurrence or expected occurrence of one or more of the following phenomena: – tropical cyclone (to be included if the 10-minute mean surface wind speed at the aerodrome is expected to be 17 m/s (34 kt) or more) – thunderstorm – hail – snow (including the expected or observed snow accumulation) – freezing precipitation – hoar frost or rime – sandstorm – duststorm – rising sand or dust – strong surface wind and gusts – squall – frost – volcanic ash – tsunami – volcanic ash deposition – toxic chemicals – other phenomena as agreed locally. Note. — Aerodrome warnings related to the occurrence or expected occurrence of tsunami are not required where a national public safety plan for tsunami is integrated with the “at risk” aerodrome concerned. 5.1.4 The use of text additional to the abbreviations listed in the template in Table A6- 2 should be kept to a minimum. The additional text should be prepared in abbreviated plain language using approved ICAO abbreviations and numerical values. If no ICAO approved abbreviations are available, English plain language text should be used. 5.2 Quantitative criteria for aerodrome warnings When quantitative criteria are necessary for the issue of aerodrome warnings covering, for example, the expected maximum wind speed or the expected total snowfall, the criteriaused should be as agreed between the aerodrome meteorological office and the users concerned. 6. Specifications related to Wind Shear Warnings 6.1 Detection of wind shear Evidence of the existence of wind shear should be derived from: a) ground-based, wind shear remote-sensing equipment, for example, Doppler radar; b) ground-based, wind shear detection equipment, for example, a system of surface wind and/or pressure sensors located in an array monitoring a specific runway or runways and associated approach and departure paths; c) aircraft observations during the climb-out or approach phases of flight to be made in accordance with Para 5; or d) other meteorological information, for example, from appropriate sensors located on existing masts or towers in the vicinity of the aerodrome or nearby areas of high ground. Note. — Wind shear conditions are normally associated with the following phenomena: — thunderstorms, microbursts, funnel cloud (tornado or waterspout), and gust fronts — strong surface winds coupled with local topography — sea breeze fronts — mountain waves (including low-level rotors in the terminal area) — low-level temperature inversions. 6.2 Format and dissemination of wind shear warnings and alerts Note. — Information on wind shear is also to be included as supplementary information in local routine reports, local special reports, METAR and SPECI in accordance with the templates in Tables A3-1 and A3-2. 6.2.1 The wind shear warnings shall be issued in accordance with the template in Table A6-3 and shall be disseminated in accordance with local arrangements to those concerned. 6.2.2 The sequence number referred to in the template in Table A6-3 shall correspond with the number of wind shear warnings issued for the aerodrome since 0001 UTC on the day concerned. 6.2.3 The use of text additional to the abbreviations listed in the template in Table A6- 3 should be kept to a minimum. The additional text should be prepared in abbreviated plain language using approved ICAO abbreviations and numerical values. If no ICAO approved abbreviations are available, English plain language text should be used.6.2.4 When an aircraft report is used to prepare a wind shear warning, or to confirm a warning previously issued, the corresponding aircraft report, including the aircraft type, should be disseminated unchanged in accordance with local arrangements to those concerned. Note 1. — Following reported encounters by both arriving and departing aircraft, two different wind shear warnings may exist: one for arriving aircraft and one for departing aircraft. Note 2. — Specifications for reporting the intensity of wind shear are still undergoing development. It is recognized, however, that pilots, when reporting wind shear, may use the qualifying terms “moderate”, “strong” or “severe”, based to a large extent on their subjective assessment of the intensity of the wind shear encountered. 6.2.5 The wind shear alerts shall be disseminated from automated, ground-based; wind shear remote-sensing or detection equipment in accordance with local arrangements to those concerned. 6.2.6 Where microbursts are observed, reported by pilots or detected by ground- based, wind shear detection or remote-sensing equipment, the wind shear warning and wind shear alert should include a specific reference to microburst. 6.2.7 Where information from ground-based, wind shear detection or remote-sensing equipment is used to prepare a wind shear alert, the alert shall, if practicable, relate to specific sections of the runway and distances along the approach path or take-off path as agreed between the meteorological authority, the appropriate ATS authority and the operators concerned.Table A6-1A. Template for SIGMET and AIRMET messages Key: M = inclusion mandatory, part of every message; C = inclusion conditional, included whenever applicable; = = a double line indicates that the text following it should be placed on the subsequent line. Note 1.— The ranges and resolutions for the numerical elements included in SIGMET/AIRMET messages are shown in Table A6-4 of this appendix. Note 2. — In accordance with 1.1.5 and 2.1.5, severe or moderate icing and severe or moderate turbulence (SEV ICE, MOD ICE, SEV TURB, MOD TURB) associated with thunderstorms, cumulonimbus clouds or tropical cyclones should not be included. SIGMET message AIRMET message Element Detailed content SIGMET template AIRMET template examples examples Location indicator of FIR/CTA ICAO location indicator of nnnn YUCC2 (M)1 the ATS unit serving the YUDD2 FIR or CTA to which the SIGMET/AIRMET refers Identification (M) Message identification and SIGMET [n][n]n AIRMET [n][n]n SIGMET 1 AIRMET 9 sequence number3 SIGMET 01 AIRMET 19 SIGMET A01 AIRMET B19 Validity period (M) Day-time groups indicating VALID nnnnnn/nnnnnn VALID 010000/010400 the period of validity in VALID 221215/221600 UTC VALID 101520/101800 VALID 251600/252200 VALID 152000/160000 VALID 192300/200300 Location indicator of MWO (M) Location indicator of MWO nnnn– YUDO–2 originating the message YUSO–2 with a separating hyphen Name of the FIR/CTA (M) Location indicator and nnnn nnnnnnnnnn nnnn nnnnnnnnnn YUCC AMSWELL FIR2 YUCC AMSWELL FIR/22 name of the FIR/CTA4 for FIR FIR[/n] YUDD SHANLON2 YUDD SHANLON FIR2 which the or FIR/UIR2 SIGMET/AIRMET is issued UIR UIR or FIR/UIR FIR/UIR YUDD SHANLON CTA2 or nnnn nnnnnnnnnn CTA IF THE SIGMET OR AIRMET MESSAGE IS TO BE CANCELLED, SEE DETAILS AT THE END OF THE TEMPLATE. Status indicator (C)5 Indicator of test or exercise TEST or EXER TEST or EXER TEST TEST EXER EXERSIGMET message AIRMET message Element Detailed content SIGMET template AIRMET template examples examples Phenomenon (M)6 Description of OBSC7 TS[GR8] SFC WIND nnn/nn[n]MPS OBSC TS SFC WIND 040/40MPS phenomenon causing the EMBD9 TS[GR8] (or OBSC TSGR SFC WIND 310/20KT issuance of FRQ10 TS[GR8] SFC WIND nnn/nn[n]KT) EMBD TS SIGMET/AIRMET SQL11 TS[GR8] EMBD TSGR SFC VIS 1500M (BR) SFC VIS [n][n]nnM (nn)16 FRQ TS TC nnnnnnnnnn PSN FRQ TSGR ISOL TS Nnn[nn] or Snn[nn] ISOL17 TS[GR8] SQL TS ISOL TSGR Wnnn[nn] or Ennn[nn] CB OCNL18 TS[GR8] SQL TSGR OCNL TS or TC NN12 PSN Nnn[nn] OCNL TSGR or Snn[nn] Wnnn[nn] MT OBSC TC GLORIA PSN N10 or Ennn[nn] CB W060 CB MT OBSC BKN CLD TC NN PSN S2030 SEV TURB13 nnn/[ABV][n]nnnM E06030 CB BKN CLD 120/900M SEV ICE14 (or BKN CLD BKN CLD 400/3000FT SEV ICE (FZRA)14 [n]nnn/[ABV][n]nnnnFT) SEV TURB BKN CLD 1000/5000FT SEV MTW15 or BKN CLD SEV ICE BKN CLD SFC/3000M SFC/[ABV][n]nnnM SEV ICE (FZRA) BKN CLD SFC/ABV10000FT HVY DS (or BKN CLD SEV MTW HVY SS SFC/[ABV][n]nnnnFT) HVY DS OVC CLD 270/ABV3000M OVC CLD HVY SS OVC CLD 900/ABV10000FT [VA ERUPTION] nnn/[ABV][n]nnnM OVC CLD1000/5000FT [MT nnnnnnnnnn] (or OVC CLD VA ERUPTION MT OVC CLD SFC/3000M [PSN Nnn[nn] or Snn[nn] [n]nnn/[ABV][n]nnnnFT) ASHVAL2 PSN S15 E073 OVC CLD SFC/ABV10000FT Ennn[nn] or Wnnn[nn]] or OVC CLD VA CLD VA CLD SFC/[ABV][n]nnnM ISOL CB (or OVC CLD RDOACT CLD OCNL CB RDOACT CLD SFC/[ABV][n]nnnnFT) FRQ CB ISOL17 CB19 ISOL TCU OCNL18 CB19 OCNL TCU FRQ10 CB19 FRQ TCU ISOL17 TCU19 MOD TURB OCNL18 TCU19 MOD ICE FRQ10 TCU19 MOD MTW MOD TURB13 MOD ICE14 MOD MTW15 Observed or forecast Indication whether the OBS [AT nnnnZ] or OBS phenomenon (M)20, 21 information is observed FCST [AT nnnnZ] OBS AT 1210Z and expected to continue, FCST or forecast FCST AT 1815ZSIGMET message AIRMET message Element Detailed content SIGMET template AIRMET template examples examples Location (C)20, 21, 33 Location (referring to Nnn[nn] Wnnn[nn] or Nnn[nn] Ennn[nn] or N2020 W07005 latitude and longitude (in Snn[nn] Wnnn[nn] or Snn[nn] Ennn[nn] N48 E010 degrees and minutes)) S60 W160 or S0530 E16530 N OF Nnn[nn] or S OF Nnn[nn] or N OF Snn[nn] or S OF Snn[nn] [AND] N OF N50 W OF Wnnn[nn] or E OF Wnnn[nn] or W OF Ennn[nn] or S OF N5430 E OF Ennn[nn] N OF S10 S OF S4530 or W OF W155 N OF Nnn[nn] or N OF Snn[nn] AND S OF Nnn[nn] or E OF W45 S OF Snn[nn] W OF E15540 E OF E09015 or W OF Wnnn[nn] or W OF Ennn[nn] AND N OF N1515 AND W OF E13530 E OF Wnnn[nn] or E OF Ennn[nn] S OF N45 AND N OF N40 or N OF LINE S2520 W11510 – S2520 W12010 N OF LINE22 or NE OF LINE22 or E OF LINE22 or SE OF SW OF LINE N50 W005 – N60 W020 LINE22 or S OF LINE22 or SW OF LINE22 or W OF LINE22 SW OF LINE N50 W020 – N45 E010 AND NE OF LINE or NW OF LINE22 Nnn[nn] or Snn[nn] Wnnn[nn] or N45 W020 – N40 E010 Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] [– Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]] [– Nnn[nn] WI N6030 E02550 – N6055 E02500 – or Snn[nn] Wnnn[nn] or Ennn[nn]] N6050 E02630 – N6030 E02550 [AND N OF LINE22 or NE OF LINE22 or E OF LINE22 or SE OF LINE22 or S OF LINE22 or SW OF LINE22 or W OF APRX 50KM WID LINE BTN N64 W017 – N60 W010 – LINE22 or NW OF LINE22 Nnn[nn] or Snn[nn] Wnnn[nn] or N57 E010 Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] [– Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]] [– Nnn[nn] ENTIRE FIR or Snn[nn] Wnnn[nn] or Ennn[nn]]] ENTIRE UIR or ENTIRE FIR/UIR WI22, 23 Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – ENTIRE CTA Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – WI 400KM OF TC CENTRE [Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – WI 250NM OF TC CENTRE Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]] † or APRX nnKM WID LINE22 BTN (or nnNM WID LINE22 BTN) Nnn[nn] or Snn[1nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] [– Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]] [– Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]] or ENTIRE UIR or ENTIRE FIR or ENTIRE FIR/UIR or ENTIRE CTA or24 WI nnnKM (or nnnNM) OF TC CENTRE or25 WI nnKM (or nnNM) OF Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]SIGMET message AIRMET message Element Detailed content SIGMET template AIRMET template examples examples Level (C)20, 21 Flight level or altitude [SFC/]FLnnn or FL180 [SFC/]nnnnM (or [SFC/][n]nnnnFT) or SFC/FL070 FLnnn/nnn or SFC/3000M TOP FLnnn or SFC/10000FT [TOP] ABV FLnnn (or [TOP] ABV [n]nnnnFT) FL050/080 [nnnn/]nnnnM (or [[n]nnnn/][n]nnnnFT) or [nnnnM/]FLnnn TOP FL390 (or [[n]nnnnFT/]FLnnn) ABV FL250 TOP ABV FL100 or 24 ABV 7000FT TOP [ABV or BLW] FLnnn TOP ABV 9000FT TOP ABV 10000FT 3000M 2000/3000M 8000FT 6000/12000FT 2000M/FL150 10000FT/FL250 TOP FL500 TOP ABV FL500 TOP BLW FL450 Movement or expected Movement or expected MOV N [nnKMH] or MOV NNE [nnKMH] or MOV SE movement (C)20, 26, 34 movement (direction and MOV NE [nnKMH] or MOV ENE [nnKMH] or MOV NNW speed) with reference to MOV E [nnKMH] or MOV ESE [nnKMH] or one of the sixteen points MOV SE [nnKMH] or MOV SSE [nnKMH] or MOV E 40KMH of compass, or stationary MOV S [nnKMH] or MOV SSW [nnKMH] or MOV E 20KT MOV SW [nnKMH] or MOV WSW [nnKMH] or MOV WSW 20KT MOV W [nnKMH] or MOV WNW [nnKMH] or MOV NW [nnKMH] or MOV NNW [nnKMH] STNR (or MOV N [nnKT] or MOV NNE [nnKT] or MOV NE [nnKT] or MOV ENE [nnKT] or MOV E [nnKT] or MOV ESE [nnKT] or MOV SE [nnKT] or MOV SSE [nnKT] or MOV S [nnKT] or MOV SSW [nnKT] or MOV SW [nnKT] or MOV WSW [nnKT] or MOV W [nnKT] or MOV WNW [nnKT] or MOV NW [nnKT] or MOV NNW [nnKT]) or STNR Changes in intensity (C)20 Expected changes in INTSF or INTSF intensity WKN or WKN NC NC Forecast time (C)20, 21, 26 Indication of the forecast FCST AT nnnnZ — FCST AT 2200Z — time of phenomenon TC forecast position (C)24 Forecast position of TC TC CENTRE PSN Nnn[nn] — TC CENTRE PSN N1030 — centre at the end of the or Snn[nn] Wnnn[nn] E16015 validity period of the or Ennn[nn] or31 TC CENTRE PSN N1015 SIGMET message TC CENTRE PSN Nnn[nn] E15030 CB or Snn[nn] Wnnn[nn] or Ennn[nn] CBSIGMET message AIRMET message Element Detailed content SIGMET template AIRMET template examples examples Forecast position (C)20, 21, 26, 27, 33 Forecast position of Nnn[nn] Wnnn[nn] or — N30 W170 — phenomenon at the end of Nnn[nn] Ennn[nn] or the validity period of the Snn[nn] Wnnn[nn] or N OF N30 SIGMET message32 Snn[nn] Ennn[nn] S OF S50 AND W OF or E170 N OF Nnn[nn] or S OF Nnn[nn] or S OF N46 AND N OF N39 N OF Snn[nn] or S OF Snn[nn] [AND] NE OF LINE N35 W020 – W OF Wnnn[nn] or N45 W040 E OF Wnnn[nn] or W OF Ennn[nn] or SW OF LINE N48 W020 – E OF Ennn[nn] N43 E010 AND NE OF LINE N43 W020 – N38 or E010 N OF Nnn[nn] or N OF Snn[nn] AND S OF WI N20 W090 – Nnn[nn] or S OF Snn[nn] N05 W090 – N10 W100 – N20 W100 – N20 W090 or W OF Wnnn[nn] or APRX 50KM WID LINE W OF Ennn[nn] AND E OF BTN N64 W017 – Wnnn[nn] or E OF Ennn[nn] N57 W005 – N55 E010 – N55 E030 or N OF LINE22 or ENTIRE FIR NE OF LINE22 or ENTIRE UIR E OF LINE22 or ENTIRE FIR/UIR SE OF LINE22 or S OF LINE22 or ENTIRE CTA SW OF LINE22 or W OF LINE22 or NO VA EXP NW OF LINE22 Nnn[nn] or Snn[nn] Wnnn[nn] or WI 30KM OF N6030 Ennn[nn] – Nnn[nn] or E02550† Snn[nn] Wnnn[nn] or Ennn[nn] WI 150NM OF TC [– Nnn[nn] or Snn[nn] CENTRE Wnnn[nn] or Ennn[nn]] [AND N OF LINE22 or NE OF LINE22 or E OF LINE22 or SE OF LINE22 or S OF LINE22 or SW OF LINE22 or W OF LINE22 or NW OF LINE22 Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] [– Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]]]SIGMET message AIRMET message Element Detailed content SIGMET template AIRMET template examples examples or WI22, 23 Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] or APRX nnKM WID LINE22 BTN (nnNM WID LINE22 BTN) Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] [– Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]] [ – Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn]] or ENTIRE FIR or ENTIRE UIR or ENTIRE FIR/UIR or ENTIRE CTA or28 NO VA EXP or25 WI nnKM (or nnNM) OF Nnn[nn] or Snn[nn] Wnnn[nn] or Ennn[nn] or24 WI nnnKM (nnnNM) OF TC CENTRE Repetition of elements (C)29 Repetition of elements [AND]29 — AND — included in a SIGMET message for volcanic ash cloud or tropical cyclone OR Cancellation of SIGMET/ Cancellation of CNL SIGMET [n][n]n CNL AIRMET [n][n]n CNL SIGMET 2 CNL AIRMET 05 AIRMET (C)30 SIGMET/AIRMET referring nnnnnn/nnnnnn nnnnnn/nnnnnn 101200/101600 151520/151800 to its identification or28 CNL SIGMET A13 CNL SIGMET 251030/251430 VA MOV [n][n]n nnnnnn/nnnnnn TO YUDO FIR2 VA MOV TO nnnn FIRNotes. — 1. See 4.1. 2. Fictitious location. 3. In accordance with 1.1.3 and 2.1.2. 4. See 2.1.3. 5. Used only when the message issued to indicate that a test or an exercise is taking place. When the word “TEST” or the abbreviation “EXER” is included, the message may contain information that should not be used operationally or will otherwise end immediately after the word "TEST". [Applicable 7 November 2019] 6. In accordance with 1.1.4 and 2.1.4. 7. In accordance with 4.2.1 a). 8. In accordance with 4.2.4. 9. In accordance with 4.2.1 b). 10. In accordance with 4.2.2. 11. In accordance with 4.2.3. 12. Used for unnamed tropical cyclones. 13. In accordance with 4.2.5 and 4.2.6. 14. In accordance with 4.2.7. 15. In accordance with 4.2.8. 16. In accordance with 2.1.4. 17. In accordance with 4.2.1 c). 18. In accordance with 4.2.1 d). 19. The use of cumulonimbus (CB) and towering cumulus (TCU) is restricted to AIRMETs in accordance with 2.1.4. 20. In the case of volcanic ash cloud covering more than one area within the FIR, these elements can be repeated, as necessary. Each location and forecast position is to be preceded by an observed or forecast time. 21. In the case of cumulonimbus clouds associated with a tropical cyclone covering more than one area within the FIR, these elements can be repeated as necessary. Each location and forecast position must be preceded by an observed or forecast time. 22. A straight line is to be used between two points drawn on a map in the Mercator projection or between two points which crosses lines of longitude at a constant angle. 23. The number of coordinates are to be kept to a minimum and should not normally exceed seven. 24. Only for SIGMET messages for tropical cyclones. 25. Only for SIGMET messages for radioactive cloud. When detailed information on the release is not available, a radius of up to 30 kilometres (or 16 nautical miles) from the source can be applied; and a vertical extent from surface (SFC) to the upper limit of the flight information region/upper flight information region (FIR/UIR) or control area (CTA) is to be applied. [Applicable from 7 November 2019 until 4 November 2020] 26. Only for SIGMET messages for radioactive cloud. A radius of up to 30 kilometres (or 16 nautical miles) from the source and a vertical extent from surface (SFC) to the upperlimit of the flight information region/upper flight information region (FIR/UIR) or control area (CTA) is to be applied. [Applicable 5 November 2020] 25. The elements “forecast time” and “forecast position” are not to be used in conjunction with the element “movement or expected movement”. 26. The levels of the phenomena remain fixed throughout the forecast period. 27. Only for SIGMET messages for volcanic ash. 28. To be used for more than one volcanic ash clouds or cumulonimbus clouds associated with a tropical cyclone simultaneously affecting the FIR concerned. 29. End of the message (as the SIGMET/AIRMET message is being cancelled). 30. The term CB is to be used when the forecast position for the cumulonimbus cloud is included. 31. The forecast position for cumulonimbus (CB) cloud occurring in connection with tropical cyclones relate to the forecast time of the tropical cyclone centre position, not to the end of the validity period of the SIGMET message. 32. For SIGMET messages for radioactive cloud, only within (WI) is to be used for the elements “location” and “forecast position”. 33. For SIGMET messages for radioactive cloud, only stationary (STNR) is to be used for the element “movement or expected movement”.Table A6-1B. Template for special air-reports (uplink) Key: M = inclusion mandatory, part of every message; C = inclusion conditional, included whenever applicable; = = a double line indicates that the text following it should be placed on the subsequent line. Note. — The ranges and resolutions for the numerical elements included in special air- reports are shown in Table A6-4 of this appendix. Element Detailed content Template1,2 Examples Identification (M) Message identification ARS ARS Aircraft identification (M) Aircraft radiotelephony call sign nnnnnn VA8123 Observed phenomenon (M) Description of observed TS TS phenomenon causing the TSGR TSGR issuance of the special air- report4 SEV TURB SEV TURB SEV ICE SEV ICE SEV MTW SEV MTW HVY DS HVY DS HVY SS HVY SS VA CLD VA CLD VA [MT nnnnnnnnnn] VA VA MT ASHVAL5 MOD TURB MOD ICE MOD TURB MOD ICE Observation time (M) Time of observation of OBS AT nnnnZ OBS AT 1210Z observed phenomenon Observed location (C) Location (referring to latitude NnnnnWnnnnn or N2020W07005 and longitude (in degrees and NnnnnEnnnnn or S4812E01036 minutes)) of observed SnnnnWnnnnn or phenomenon SnnnnEnnnnn Observed level (C) Flight level or altitude of FLnnn or FL390 observed phenomenon FLnnn/nnn or FL180/210 nnnnM (or [n]nnnnFT) 3000M 12000FT Notes. — 1. No wind and temperature to be uplinked to other aircraft in flight in accordance with 3.2. 2. 2. See 3.1. 3. Fictitious call sign. 4. In the case of special air-report for volcanic ash cloud, the vertical extent (if observed) and name of the volcano (if known) can be used. 5. Fictitious location.Table A6-2. Template for aerodrome warnings Key: M = inclusion mandatory, part of every message; C = inclusion conditional, included whenever applicable; Note 1.— The ranges and resolutions for the numerical elements included in aerodrome warnings are shown in Table A6-4 of this appendix. Note 2.— The explanations for the abbreviations can be found in the Procedures for Air Navigation Services — ICAO Abbreviations and Codes (PANS-ABC, Doc 8400). Element Detailed content Templates Examples Location indicator of the Location indicator of the aerodrome nnnn YUCC1 aerodrome (M) Identification of the type of Type of message and sequence number AD WRNG [n]n AD WRNG 2 message (M) Validity period (M) Day and time of validity period in UTC VALID nnnnnn/nnnnnn VALID 211230/211530 IF THE AERODROME WARNING IS TO BE CANCELLED, SEE DETAILS AT THE END OF THE TEMPLATE. Phenomenon (M)2 Description of phenomenon causing the TC3 nnnnnnnnnn or TC ANDREW issuance of the aerodrome warning [HVY] TS or HVY SN 25CM GR or SFC WSPD 20MPS MAX 30 [HVY] SN [nnCM]3 or VA [HVY] FZRA or [HVY] FZDZ or TSUNAMI RIME4 or [HVY] SS or [HVY] DS or SA or DU or SFC WSPD nn[n]MPS MAX nn[n] (SFC WSPD nn[n]KT MAX nn[n]) or SFC WIND nnn/nn[n]MPS MAX nn[n] (SFC WIND nnn/nn[n]KT MAX nn[n]) or SQ or FROST or TSUNAMI or VA[DEPO] or TOX CHEM or Free text up to 32 characters5 Observed or forecast Indication whether the information is OBS [AT nnnnZ] or OBS AT 1200Z phenomenon (M) observed and expected to continue, or FCST OBS forecast Changes in intensity (C) Expected changes in intensity INTSF or WKN WKN or NC OR Cancellation of aerodrome Cancellation of aerodrome warning CNL AD WRNG [n]n nnnnnn/nnnnnn CNL AD WRNG 2 211230/2115306 warning6 referring to its identification Notes. — 1. Fictitious location. 2. One phenomenon or a combination thereof, in accordance with 5.1.3. 3. In accordance with 5.1.3. 4. Hoar frost or rime in accordance with 5.1.3.5. In accordance with 5.1.4. 6. End of the message (as the aerodrome warning is being cancelled). Table A6-3. Template for wind shear warnings Key: M = inclusion mandatory, part of every message; C = inclusion conditional, included whenever applicable; Note 1.— The ranges and resolutions for the numerical elements included in wind shear warnings are shown in Table A6-4 of this appendix. Note 2.— The explanations for the abbreviations can be found in the PANS-ABC (Doc 8400). Element Detailed content Template(s) Examples Location indicator of the Location indicator of the aerodrome nnnn YUCC1 aerodrome (M) Identification of the type of Type of message and sequence WS WRNG [n]n WS WRNG 1 message (M) number Time of origin and validity period (M) Day and time of issue and, where nnnnnn [VALID TL nnnnnn] or 211230 VALID TL 211330 applicable, validity period in UTC [VALID nnnnnn/nnnnnn] 221200 VALID 221215/221315 IF THE WIND SHEAR WARNING IS TO BE CANCELLED, SEE DETAILS AT THE END OF THE TEMPLATE. Phenomenon (M) Identification of the phenomenon and [MOD] or [SEV] WS IN APCH or WS APCH RWY12 its location [MOD] or [SEV] WS [APCH] RWYnnn MOD WS RWY34 or [MOD] or [SEV] WS IN CLIMB-OUT WS IN CLIMB-OUT or [MOD] or [SEV] WS CLIMB-OUT RWYnnn or MBST APCH RWY26 MBST IN APCH or MBST [APCH] RWYnnn MBST IN CLIMB-OUT or MBST IN CLIMB-OUT or MBST CLIMB-OUT RWYnnn Observed, reported or forecast Identification whether the REP AT nnnn nnnnnnnn or REP AT 1510 B747 phenomenon (M) phenomenon is observed or reported OBS [AT nnnn] or OBS AT 1205 and expected to continue, or forecast FCST FCST Details of the phenomenon (C)2 Description of phenomenon causing SFC WIND: nnn/nnMPS (or nnn/nnKT) nnnM SFC WIND: 320/5MPS the issuance of the wind shear (nnnFT)-WIND: nnn/nnMPS (or nnn/nnKT) 60M-WIND: 360/13MPS warning or (SFC WIND: 320/10KT nnKMH (or nnKT) LOSS nnKM (or nnNM) 200FT-WIND: 360/26KT) FNA RWYnn 60KMH LOSS 4KM or FNA RWY13 nnKMH (or nnKT) GAIN nnKM (or nnNM) (30KT LOSS 2NM FNA RWYnn FNA RWY13) OR Cancellation of wind shear warning3 Cancellation of wind shear warning CNL WS WRNG [n]n nnnnnn/nnnnnn CNL WS WRNG 1 211230/2113303 referring to its identification Notes. — 1. Fictitious location. 2. Additional provisions in 6.2.3. 3. End of the message (as the wind shear warning is being cancelled).Example A6-2. SIGMET message for tropical cyclone Example A6-3. SIGMET message for volcanic ash Example A6-4. SIGMET message for radioactive cloudExample A6-5. SIGMET message for severe turbulence Example A6-6. AIRMET message for moderate mountain waveAPPENDIX 7. TECHNICAL SPECIFICATIONS RELATED TO AERONAUTICAL CLIMATOLOGICAL INFORMATION (See Para 8 of this CAR) 1. Processing of Aeronautical Climatological Information Meteorological observations for regular and alternate aerodromes should be collected, processed and stored in a form suitable for the preparation of aerodrome climatological information. 2. Exchange of Aeronautical Climatological Information Aeronautical climatological information should be exchanged on request between meteorological authorities. Operators and other aeronautical users desiring such information should normally apply to the meteorological authority responsible for its preparation. 3. Content of Aeronautical Climatological Information 3.1 Aerodrome climatological tables 3.1.1 An aerodrome climatological table should give as applicable: a) mean values and variations therefrom, including maximum and minimum values, of meteorological elements (for example, of air temperature); and/or b) the frequency of occurrence of present weather phenomena affecting flight operations at the aerodrome (for example, of sandstorms); and/or c) the frequency of occurrence of specified values of one, or of a combination of two or more, elements (for example, of a combination of low visibility and low cloud). 3.1.2 Aerodrome climatological tables should include information required for the preparation of aerodrome climatological summaries in accordance with 3.2. 3.2 Aerodrome climatological summaries Aerodrome climatological summaries should cover: a) frequencies of the occurrence of runway visual range/visibility and/or height of the base of the lowest cloud layer of BKN or OVC extent below specified values at specified times; b) frequencies of visibility below specified values at specified times; c) frequencies of the height of the base of the lowest cloud layer of BKN or OVC extentbelow specified values at specified times; d) frequencies of occurrence of concurrent wind direction and speed within specified ranges; e) frequencies of surface temperature in specified ranges of 5°C at specified times; and f) mean values and variations therefrom, including maximum and minimum values of meteorological elements required for operational planning purposes, including take- off performance calculations. Note. — Models of climatological summaries related to a) to e) are given in Technical Regulations WMO No. 49, Volume II — Meteorological Service for International Air Navigation, Part III.APPENDIX 8. TECHNICAL SPECIFICATIONS RELATED TO SERVICE FOR OPERATORS AND FLIGHT CREW MEMBERS (See Para 8 of this CAR) Note. — Specifications related to flight documentation (including the model charts and forms) are given in Appendix 1. 1. Means of supply and format of Meteorological Information 1.1 Meteorological information shall be supplied to operators and flight crew members by one or more of the following, as agreed between the meteorological authority and the operator concerned, and with the order shown below not implying priorities: a) written or printed material, including specified charts and forms; b) data in digital form; c) briefing; d) consultation; e) display; or f) in lieu of a) to e), by means of an automated pre-flight information system providing self-briefing and flight documentation facilities while retaining access by operators and aircrew members to consultation, as necessary, with the aerodrome meteorological office, in accordance with 5.1. 1.2 The meteorological authority, in consultation with the operator, shall determine: a) the type and format of meteorological information to be supplied; and b) methods and means of supplying that information. 1.3 On request by the operator, the meteorological information supplied for flight planning should include data for the determination of the lowest usable flight level. 2. Specifications related to information for Pre-flight planning and In-flight Re-planning 2.1 Format of upper-air gridded information Upper-air gridded information supplied by WAFCs for pre-flight and in-flight re- planning shall be in the GRIB code form. Note. — The GRIB code form is contained in Manual on Codes WMO No. 306, Volume I.2, Part B — Binary Codes. 2.2 Format of information on significant weather 2.2.1 Information on significant weather supplied by WAFCs for pre-flight p l a n n i n g and in-flight re- planning shall be in the BUFR code form.Note. — The BUFR code form is contained in Manual on Codes WMO No. 306, Volume I.2, Part B — Binary Codes. 2.2.2 Recommendation. — As of 4 November 2021, in addition to 2.2.1, information on significant weather supplied by WAFCs for pre-flight planning and in-flight re planning should be in IWXXM GML form. Note 1. — Guidance on the implementation of IWXXM is provided in the Manual on the ICAO Meteorological Information Exchange Model (IWXXM) (Doc 10003). Note 2. — Geography markup language (GML) is an encoding standard of the Open Geospatial Consortium (OGC). 2.3 Specific needs of helicopter operations Meteorological information for pre-flight planning and in-flight re- planning by operators of helicopters flying to offshore structures should include data covering the layers from sea level to flight level 100. Particular mention should be made of the expected surface visibility, the amount, type (where available), base and tops of cloud below flight level 100, sea state and sea-surface temperature, mean sea-level pressure, and the occurrence and expected occurrence of turbulence and icing, as determined by regional air navigation agreement. 3. Specifications related to briefing and consultation 3.1 Information required to be displayed The material displayed shall be readily accessible to the flight crew members or other flight operations personnel concerned. 4. Specifications related to information flight documentation 4.1 Presentation of information 4.1.1 The flight documentation related to forecasts of upper wind and upper-air temperature and SIGWX phenomena shall be presented in the form of charts. Note. — Models of charts and forms for use in the preparation of flight documentation are given in Appendix 1. These models and methods for their completion are developed by the WMO on the basis of relevant operational requirements stated by ICAO. 4.1.2 The flight documentation related to concatenated route-specific upper wind and upper-air temperature forecasts should be provided as agreed between the meteorological authority and the operator concerned.Note. — Guidance on the design, formulation and use of concatenated charts is given in the Manual of Aeronautical Meteorological Practice (Doc 8896). 4.1.3 METAR and SPECI (including trend forecasts as issued in accordance with regional air navigation agreement), TAF, SIGMET and tropical cyclone advisory information shall be presented in accordance with the templates in Appendices 1, 2, 3, 5 and 6. Such meteorological information received from other meteorological offices shall be included in flight documentation without change. Note. — Examples of the form of presentation of METAR/SPECI and TAF are given in Appendix 1. 4.1.4 The location indicators and the abbreviations used should be explained in the flight documentation. 4.1.5 The forms and the legend of charts included in flight documentation should be printed in English, French, Russian or Spanish. Where appropriate, approved abbreviations should be used. The units employed for each element should be indicated; they should be in accordance with Annex 5. 4.2 Charts in flight documentation 4.2.1 Characteristics of charts 4.2.1.1 Charts included in flight documentation should have a high standard of clarity and legibility and should have the following physical characteristics: a) for convenience, the largest size of charts should be about 42 × 30 cm (standard size A3) and the smallest size should be about 21 × 30 cm (standard size A4). The choice between these sizes should depend on the route lengths and the amount of detail that needs to be given in the charts as agreed between meteorological authority and users concerned; b) major geographical features, such as coastlines, major rivers and lakes should be depicted in a way that makes them easily recognizable; c) for charts prepared by computer, meteorological data should take preference over basic chart information, the former cancelling the latter wherever they overlap; d) major aerodromes should be shown as a dot and identified by the first letter of the name of the city the aerodrome serves as given in Table AOP of the relevant regional air navigation plan; e) a geographical grid should be shown with meridians and parallels represented by dotted lines at each 10° latitude and longitude; dots should be spaced one degree apart;f) latitude and longitude values should be indicated at various points throughout the charts (i.e. not only at the edges); and g) labels on the charts for flight documentation should be clear and simple and should present the name of the world area forecast centre (WAFC) or, for non- world area forecast system (WAFS) products, the originating centre, the type of chart, date and valid time and, if necessary, the types of units used in an unambiguous way. Note. — When plotting shapes, particularly polygons, on maps, appropriate corrections are necessary if plotted on projections different to that used in the production of the original forecast area. 4.2.1.2 Meteorological information included in flight documentation shall be represented as follows: a) winds on charts shall be depicted by arrows with feathers and shaded pennants on a sufficiently dense grid; b) temperatures shall be depicted by figures on a sufficiently dense grid; c) wind and temperature data selected from the data sets received from a world area forecast centre shall be depicted in a sufficiently dense latitude/longitude grid; and d) wind arrows shall take precedence over temperatures and either shall take precedence over chart background. 4.2.1.3 For short-haul flights, charts should be prepared covering limited areas at a scale of 1:15 × 106 as required. 4.2.2 Set of charts to be provided 4.2.2.1 The minimum number of charts for flights between flight level 250 and flight level 630 shall include a high-level SIGWX chart (flight level 250 to flight level 630) and a forecast 250 hPa wind and temperature chart. The actual charts Provided for pre-flight and in-flight planning and for flight documentation shall be as agreed between meteorological authorities and users concerned. 4.2.2.2 Charts to be provided shall be generated from the digital forecast provided by the WAFCs whenever these forecasts cover the intended flight path in respect of time, altitude and geographical extent, unless otherwise agreed between the meteorological authority and the operator concerned.4.2.3 Height indications In flight documentation, height indications shall be given as follows: a) all references to en-route meteorological conditions, such as height indications of upper winds, turbulence or bases and tops of clouds, shall preferably be expressed in flight levels; they may also be expressed in pressure, altitude or, for low-level flights, height above ground level; and b) all references to aerodrome meteorological conditions, such as height indications of the bases of clouds, shall be expressed in height above the aerodrome elevation. 4.3 Specifications related to low-level flights 4.3.1 In chart form Where the forecasts are supplied in chart form, flight documentation for low- level flights, including those in accordance with the visual flight rules, operating up to flight level 100 (or up to flight level 150 in mountainous areas or higher, where necessary), should contain the following as appropriate to the flight: a) information from relevant SIGMET messages; b) upper wind and upper-air temperature charts as given in Appendix 5, 4.3.1; and c) significant weather charts as given in Appendix 5, 4.3.2. 4.3.2 In abbreviated plain language Where the forecasts are not supplied in chart form, flight documentation for low-level flights, including those in accordance with the visual flight rules, operating up to flight level 100 (up to flight level 150 in mountainous areas or higher, where necessary), should contain the following information as appropriate to the flight: a) SIGMET information; and b) GAMET area forecasts. 5. Specifications related to automated pre-flight information system for briefing, consultation, flight planning and flight documentation 5.1 Access to the systems Automated pre-flight information systems providing self-briefing facilities shall provide for access by operators and flight crew members to consultation, as necessary, with anaerodrome meteorological office by telephone or other suitable telecommunications means. 5.2 Detailed specifications of the systems Automated pre-flight information systems for the supply of meteorological information for self-briefing, pre-flight planning and flight documentation should: a) provide for the continuous and timely updating of the system database and monitoring of the validity and integrity of the meteorological information stored; b) permit access to the system by operators and flight crew members and also by other aeronautical users concerned through suitable telecommunications means; c) use access and interrogation procedures based on abbreviated plain language and, as appropriate, ICAO location indicators, and aeronautical meteorological code data-type designators prescribed by the WMO, or based on a menu-driven user interface, or other appropriate mechanisms as agreed between the meteorological authority and operators concerned; and d) provide for rapid response to a user request for information. Note. — ICAO abbreviations and codes and location indicators are given respectively in the Procedures for Air Navigation Services — ICAO Abbreviations and Codes (PANS- ABC, Doc 8400) and Location Indicators (Doc 7910). Aeronautical meteorological code data-type designators are given in the Manual on the Global Telecommunication System (WMO No. 386). 6. Specifications related to Information for aircraft in flight 6.1 Supply of information requested by an aircraft in flight If an aircraft in flight requests meteorological information, the aerodrome meteorological office or meteorological watch office which receives the request should arrange to supply the information with the assistance, if necessary, of another aerodrome meteorological office or meteorological watch office. 6.2 Information for in-flight planning by the operator Meteorological information for planning by the operator for aircraft in flight should be supplied during the period of the flight and should normally consist of any or all of the following: a) METAR and SPECI (including trend forecasts as issued in accordance with regional air navigation agreement);b) TAF and amended TAF; c) SIGMET relevant to the flight, unless the latter have been the subject of a SIGMET message; d) upper wind and upper-air temperature information; e) volcanic ash and tropical cyclone advisory information relevant to the flight; and f) other meteorological information in alphanumeric or graphical form as agreed between the meteorological authority and the operator concerned. Note. — Guidance on the display of graphical information in the cockpit is provided in the Manual of Aeronautical Practice (Doc 8896).APPENDIX 9. TECHNICAL SPECIFICATIONS RELATED TO INFORMATION FOR AIR TRAFFIC SERVICE, SEARCH AND RESCUE SERVICE AND AERONAUTICAL INFORMATION SERVICES (See Para 10 of this CAR) 1. Information to be provided for Air Traffic Services Units 1.1 List of information for the aerodrome control tower The following meteorological information shall be supplied, as necessary, to an aerodrome control tower by its associated aerodrome meteorological office: a) local routine reports, local special reports, METAR, SPECI, TAF, trend forecasts and amendments thereto, for the aerodrome concerned; data in digital form; b) SIGMET information, wind shear warnings and alerts and aerodrome warnings; c) any additional meteorological information agreed upon locally, such as forecasts of surface wind for the determination of possible runway changes; d) information received on volcanic ash cloud, for which a SIGMET has not already been issued; and e) information received on pre-eruption volcanic activity and/or a volcanic eruption as agreed between the meteorological and ATS authorities concerned. 1.2 List of information for the approach control unit The following meteorological information shall be supplied, as necessary, to an approach control unit by its associated aerodrome meteorological office: a) local routine reports, local special reports, METAR, SPECI, TAF, trend forecasts and amendments thereto, for the aerodrome(s) with which the approach control unit is concerned; b) SIGMET information, wind shear warnings and alerts for the airspace with which the approach control unit is concerned and aerodrome warning c) S; d) any additional meteorological information agreed upon locally; e) information received on volcanic ash cloud, for which a SIGMET has not already been issued, as agreed between the meteorological and ATS authorities concerned; and f) information received on pre-eruption volcanic activity and/or a volcanic eruption as agreed between the meteorological and ATS authorities concerned. 1.3 List of information for the area control centre (ACC) and Flight Information centre (FIC) The following meteorological information shall be supplied, as necessary, to an area control centre (ACC) or a flight information centre (FIC) by its associated meteorological watch office: a) METAR and SPECI, including current pressure data for aerodromes and other locations, TAFand trend forecasts and amendments thereto, covering the flight information region ( F I R ) or the control area ( C T A ) and, if required by the flight information centre (FIC) or area control centre (ACC), covering aerodromes in neighbouring FIRs, as determined by regional air navigation agreement; b) forecasts of upper winds, upper-air temperatures and significant en-route weather phenomena and amendments thereto, particularly those which are likely to make operation under visual flight rules impracticable, SIGMET information and appropriate special air-reports for the FIR or CTA and, if determined by regional air navigation agreement and required by the FIC or ACC, for neighbouring FIRs; c) any other meteorological information required by the FIC or ACC to meet requests from aircraft in flight; if the information requested is not available in the associated MWO, that office shall request the assistance of another meteorological office in supplying it; d) information received on volcanic ash cloud, for which a SIGMET has not already been issued as agreed between the meteorological and ATS authorities concerned; e) information received concerning the release of radioactive materials into the atmosphere as agreed between the meteorological and ATS authorities concerned; f) tropical cyclone advisory information issued by a TCAC in its area of responsibility; g) volcanic ash advisory information issued by a VAAC in its area of responsibility; and h) information received on pre-eruption volcanic activity and/or a volcanic eruption. 1.4 Supply of information to aeronautical telecommunications stations Where necessary for flight information purposes, current meteorological reports and forecasts shall be supplied to designated aeronautical telecommunication stations. A copy of such information shall be forwarded, if required, to the FIC or ACC. 1.5 Format of information 1.5.1 Local routine report, local secial reports, METAR, SPECI, TAF, trend forecasts, SIGMET information, upper wind and upper-air temperature forecasts and amendments thereto should be supplied to air traffic services units in the form in which they are prepared, disseminated to other aerodrome meteorological offices or MWOs or received from other aerodrome meteorological offices or MWOs, unless otherwise agreed locally. 1.5.2 When computer-processed upper-air data for grid points are made available to air traffic services units in digital form for use by air traffic services computers, the contents, format and transmission arrangements should be as agreed between the meteorological authority and the appropriate ATS authority. The data should normally be supplied as soon as is practicable after the processing of the forecasts has been completed. 2. Information to be provided for Search and Rescue Services Units 2.1 List of Information Information to be supplied to rescue coordination centres shall include the meteorological conditions that existed in the last known position of a missing aircraft and along the intended routeof that aircraft with particular reference to: a) significant en-route weather phenomena; b) cloud amount and type, particularly cumulonimbus; height indications of bases and tops; c) visibility and phenomena reducing visibility; d) surface wind and upper wind; e) state of ground, in particular, any snow cover or flooding; f) sea-surface temperature, state of the sea, ice cover if any and ocean currents, if relevant to the search area; and g) sea-level pressure data. 2.2 Information to be provided on request 2.2.1 On request from the rescue coordination centre, the designated aerodrome meteorological office or MWO should arrange to obtain details of the flight documentation which was supplied to the missing aircraft, together with any amendments to the forecast which were transmitted to the aircraft in flight. 2.2.2 To facilitate search and rescue operations, the designated aerodrome meteorological office or MWO should, on request, supply: a) complete and detailed information on the current and forecast meteorological conditions in the search area; and b) current and forecast conditions en route, covering flights by search aircraft from and returning to the aerodrome from which the search is being conducted. 2.2.3 On request from the rescue coordination centre, the designated aerodrome meteorological office or MWO should supply or arrange for the supply of meteorological information required by ships undertaking search and rescue operations. 3. Information to be provided for Aeronautical Information Service Units 3.1 List of information The following information shall be supplied, as necessary, to an aeronautical information services unit: a) information on meteorological service for international air navigation, intended for inclusion in the aeronautical information publication(s) concerned; Note.— Details of this information are given in PANS-AIM, Appendix 3, Part 1, GEN 3.5 and Part 3, AD 2.2, 2.11, 3.2 and 3.11. b) information necessary for the preparation of NOTAM or ASHTAM including, in particular, information on: 1) the establishment, withdrawal and significant changes in operation of aeronauticalmeteorological services. This information is required to be provided to the aeronautical information services unit sufficiently in advance of the effective date to permit issuance of NOTAM in compliance with Annex 15, 3.2.2 and 3.2.3; 2) the occurrence of volcanic activity; and Note. — The specific information required is given in Para 3, 3.3.2 and Para 4, 4.8 of this CAR. 3) release of radioactive materials into the atmosphere as agreed between the meteorological and appropriate civil aviation authorities concerned; and Note. — The specific information required is given in Para 3, 3.4.2 g) of this CAR. c) information necessary for the preparation of aeronautical information circulars including, in particular, information on: 1) expected important changes in aeronautical meteorological procedures, services and facilities provided; and 2) effect of certain weather phenomena on aircraft operations.APPENDIX 10. TECHNICAL SPECIFICATIONS RELATED TO REQUIREMENTS FOR AND USE OF COMMUNICATIONS (See Para 11 of this CAR) 1. Specific requirements for communication 1.1 Required transit times of operational meteorological information Messages and bulletins containing operational meteorological information shall achieve transit times of less than 5 minutes, unless otherwise determined to be lower by regional air navigation agreement. 1.2 Grid point data for ATS and operators 1.2.1 When upper-air data for grid points in digital form are made available for use by air traffic services computers, the transmission arrangements should be as agreed between the meteorological authority and the appropriate ATS authority. 1.2.2 When upper-air data for grid points in digital form are made available to operators for flight planning by computer, the transmission arrangements should be as agreed among the WAFC concerned, the meteorological authority and the operators concerned. 2. Use of Aeronautical Fixed Service Communication and Public Internet 2.1 Meteorological bulletins in alphanumeric format 2.1.1 Composition of bulletins Whenever possible, exchanges of operational meteorological information should be made in consolidated bulletins of the same types of meteorological information. 2.1.2 Filing times of bulletins Meteorological bulletins required for scheduled transmissions should be filed regularly and at the prescribed scheduled times. METAR should be filed for transmission not later than 5 minutes after the actual time of observation. TAF should be filed for transmission not earlier than one hour prior to the beginning of their validity period. 2.1.3 Heading of bulletins Meteorological bulletins containing operational meteorological information to be transmitted via the aeronautical fixed service or the public Internet shall contain a heading consisting of: a) an identifier of four letters and two figures;b) the ICAO four-letter location indicator corresponding to the geographical location of the meteorological office originating or compiling the meteorological bulletin; c) a day-time group; and d) if required, a three-letter indicator. Note 1.— Detailed specifications on format and contents of the heading are given in Manual on the Global Telecommunication System, WMO No. 386 and are reproduced in the Manual of Aeronautical Meteorological Practice (Doc 8896). Note 2.— ICAO location indicators are listed in Location Indicators (Doc 7910). 2.1.4 Transmission of bulletins containing operational meteorological information Meteorological bulletins containing operational meteorological information shall be transmitted via the aeronautical fixed service (AFS). 2.2 World area forecast system (WAFS) products 2.2.1 Telecommunications for the supply of WAFS products The telecommunications facilities used for the supply of WAFS productsshould be the aeronautical fixed service or the public Internet.. 2.2.2 Quality requirements for charts Where WAFS products are disseminated in chart form, the quality of the charts received should be such as to permit reproduction in a sufficiently legible form for flight planning and documentation. Charts received should be legible over 95 per cent of their area. 2.2.3 Quality requirements for transmissions Transmissions should be such as to ensure that their interruption should not exceed 10 minutes during any period of 6 hours. 2.2.4 Heading of bulletins containing WAFS products Meteorological bulletins containing WAFS products in digital form to be transmitted via aeronautical fixed service or the public Internet shall contain a heading as given in 2.1.3. 3. Use of Aeronautical Mobile Service Communications 3.1 Content and format of meteorological messages3.1.1 The content and format of reports, forecasts and SIGMET information transmitted to aircraft shall be consistent with the provisions of Para 4, 6 and 7 of this CAR. 3.1.2 The content and format of air-reports transmitted by aircraft shall be consistent with the provisions of Para 5 of this CAR and the Procedures for Air Navigation Services — Air Traffic Management (PANS-ATM, Doc 4444), Appendix 1. 3.2 Content and format of meteorological bulletins The substance of a meteorological bulletin transmitted via the aeronautical mobile service shall remain unchanged from that contained in the bulletin as originated. 4. Intentionally left blank 5. Use of Aeronautical Broadcasting Service — VOLMET Broadcasts 5.1 Detailed content of meteorological information to be included in VOLMET broadcasts 5.1.1 The aerodromes for which METAR, SPECI and TAF are to be included in VOLMET broadcasts, the sequence in which they are to be transmitted and the broadcast time shall be determined by regional air navigation agreement. 5.1.2 The flight information regions for which SIGMET messages are to be included in scheduled VOLMET broadcasts shall be determined by regional air navigation agreement. Where this is done, the SIGMET message shall be transmitted at the beginning of the broadcast or of a five-minute time block. 5.2 Criteria related to information to be included in VOLMET broadcasts 5.2.1 When a report has not arrived from an aerodrome in time for a broadcast, the latest available report should be included in the broadcast, together with the time of observation. 5.2.2 TAF included in scheduled VOLMET broadcasts should be amended as necessary to ensure that a forecast, when transmitted, reflects the latest opinion of the aerodrome meteorological office concerned. 5.2.3 Where SIGMET messages are included in scheduled VOLMET broadcasts, an indication of “NIL SIGMET” should be transmitted if no SIGMET message is valid for the FIRs concerned. 5.3 Format of information to be included in VOLMET broadcasts 5.3.1 The content and format of reports, forecasts and SIGMET information included in VOLMET broadcasts shall be consistent with the provisions of Para 4, 6 and 7 of this CAR. 5.3.2 VOLMET broadcasts should use standard radiotelephony phraseologies.Note.— Guidance on the standard radiotelephony phraseologies to be used in VOLMET broadcasts is given in the Manual on Coordination between Air Traffic Services, Aeronautical Information Services and Aeronautical Meteorological Services (Doc 9377), Appendix 1.ATTACHMENT A. OPERATINALLY DESIRABLE ACCURACY OF MEASUREMENT OR OBSERVATIION Note. — The guidance contained in this table relates to Chapter 2, 2.2, in particular to 2.2.7, and Chapter 4. Note. — Guidance on the uncertainties of measurement or observation can be found in the Guide to Meteorological Instruments and Methods of Observation (WMO-No. 8).ATTACHMENT B. OPERATINALLY DESIRABLE ACCURACY OF FORECASTS Note 1.— The guidance contained in this table relates to Chapter 2, 2.2, in particular to 2.2.8, and Chapter 6. Note 2.— If the accuracy of the forecasts remains within the operationally desirable range shown in the second column, for the percentage of cases indicated in the third column, the effect of forecast errors is not considered serious in comparison with the effects of navigational errors and of other operational uncertainties.ATTACHMENT C. SELECTED CRITERIA APPLICABLE TO AERODROME REPORTS (The guidance in this table relates to Chapter 4 and Appendix 3.) Notes— 1. considered for the past 10 minutes (exception: if the 10-minute period includes a marked discontinuity (i.e. runway visual range changes or passes 175, 300, 550 or 800 m, lasting ≥ 2 minutes), only data after the discontinuity to be used). A simple diagrammatic convention is used to illustrate those parts of the 10- minute period prior to the observation relevant to runway visual range criteria, i.e. AB, BC and AC. 2. Layer composed of CB and TCU with a common base should be reported as “CB”. 3. Considered for the past 10 minutes (exception: if the 10-minute period includes a marked discontinuity (i.e. the direction changes ≥ 30° with a speed ≥ 5 m/s or the speed changes ≥ 5 m/s lasting ≥ 2 minutes), only data after the discontinuity to be used). 4. If several directions, the most operationally significant direction used. 5. Let R 5(AB)= 5-minute mean runway visual range value during period AB and R 5(BC) = 5- minute mean runway visual range value during period BC. 6. CB (cumulonimbus) and TCU (towering cumulus = cumulus congestus of great vertical extent) if not already indicated as one of the other layers. 7. Time averaging, for mean values and, if applicable, referring period for extreme values, indicated in the upper left-hand corner. 8. According to the Manual on Codes (WMO-No. 306), Volume I.1, Part A — Alphanumeric Codes, paragraph 15.5.5, it is recommended that the wind measuring systems should be such that peak gusts should represent a three-second average”. 9. N/A = not applicable. 10. QFE is to be included if required. Reference elevation for QFE should be aerodrome elevation except for precision approach runways, and non-precision approach runways with threshold ≥ 2 m (7 ft) below or above aerodrome elevation, where the reference level should be the relevant threshold elevation. 11. As listed in Appendix 3, 4.8. 12. Also sea-surface temperature, and state of the sea or the significant wave height from offshore structures in accordance with regional air navigation agreement.13. Report if RVR and/or VIS < 1 500 m, limits for assessments 50 and 2 000 m. 14. For landing at aerodromes with precision approach runways and with the threshold elevation ≥ 15 m below the aerodrome elevation, the threshold elevation to be used as a reference. 15. Measured in 0.1 hPaATTACHMENT D. CONVERSION OF INSTRUMENTED READING INTO RUNWAY VISUAL RANGE AND VISIBILTY (See Appendix 3, 4.3.5 of this CAR) 1. The conversion of instrumented readings into runway visual range and visibility is based on Koschmieder’s Law or Allard’s Law, depending on whether the pilot can be expected to obtain main visual guidance from the runway and its markings or from the runway lights. In the interest of standardization in runway visual range assessments, this Attachment provides guidance on the use and application of the main conversionfactors to be used in these computations. 2. In Koschmieder’s Law one of the factors to be taken into account is the pilot contrast threshold. The agreed constant to be used for this is 0.05 (dimensionless). 3. In Allard’s Law the corresponding factor is the illumination threshold. This is not a constant, but a continuous function dependent on the background luminance. Theagreed relationship to be used in instrumented systems with continuous adjustment of the illumination threshold by a background luminance sensor is shown by the curve in Figure D-1. The use of a continuous function which approximates the step function such as displayed in Figure D-1 is preferred, due to its higher accuracy, to the stepped relationship described in paragraph 4. 4. In instrumented systems without continuous adjustment of the illumination threshold, the use of four equally spaced illumination threshold values with agreed corresponding back ground luminance ranges is convenient but will reduce accuracy. The four values are shown in Figure D-1 in the form of a step function; they are tabulated in Table D-1 for greater clarity. Note 1.— Information and guidance material on the runway lights to be used for assessment of runway visual range are contained in the Manual of Runway Visual Range Observing and Reporting Practices (Doc 9328). Note 2.— In accordance with the definition of visibility for aeronautical purposes, theintensity of lights to be used for the assessment of visibility is in the vicinity of 1 000 cd.ATTACHMENT E. SPATIAL RANGES AND RESOLUTIONS FOR SPACE WEATHERADVISORY INFORMATION The technical specifications related to SWXC are stipulates in Chapter 3, Appendix 2 and Attachment E of ICAO Annex 3 for the contracting states which have accepted responsibilities to monitor and provide advisory information on space weather. India is not a SWXC. However, the Service Provider shall have to be familiar with the technical specifications so as to be able to interact with SWXC and use its services effectively.