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Weather observation data is mostly used for the following purposes:
METAR reports are provided at regular intervals (usually 30 minutes) and provide essential weather information about an aerodrome. Data should be representative for the whole aerodrome operating area.
Special reports (SPECI) are be produced as dictated by the weather conditions (when there is significant deterioration or improvement in airport weather conditions, such as significant changes of surface winds, visibility, cloud base height and occurrence of severe weather). The criteria for the production of a special report and information dissemination are laid down in relevant local documents. The format of the SPECI report is similar to that of the METAR and the elements used have the same meaning. The identifier METAR or SPECI at the beginning of the weather report differentiates them.
TAF (terminal area forecast) - the aerodrome forecast consists of a concise statement of the expected meteorological conditions at an aerodrome for a specified period.
Automatic Terminal Information Service (ATIS) - is a continuous broadcast of recorded non-ATC aeronautical information.
VOLMET - a worldwide network of radio stations that broadcast TAF, SIGMET and METAR reports.
Weather reports to ATS. Weather reports to Air Traffic Services are usually issued half-hourly and are used by the ATS unit to provide weather information to operators, aerodrome users and pilots at or in the vicinity of the aerodrome. Whilst these reports are very similar to the METAR, there are slight differences in content and coding.
Provision Architecture
The aerodrome weather observations are defined as a the responsibility of the designated Aerodrome Meteorological Station.
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An Aerodrome Meteorological Observation Information Service will be used primarily by:
Air Traffic Service Providers
Airspace Users including General Aviation and Business Aviation industries.
Airports
Aerodrome Meteorological Stations
Consumer Usage
METARs are disseminated both to operators at the aerodrome concerned and where required internationally to all those who may need to use the airfield concerned. Meteorological information for international scheduled air traffic normally consists of documentation and if necessary briefing/consultation. The documentation is supplied to the pilot-in-command via self-briefing terminal or via airport operators.Air Traffic Service Providers
Updates to ATIS and VOLMET
Issuance of NOTAMS or SNOWTAMS
Local operating decisions such as runway changes or halting operations during adverse weather.
Airspace Users including General Aviation and Business Aviation industries.
Operators, flight dispatchers, flight crew members and flight operations centres
Both in the pre flight planning phases and also updates enroute
Airports
Local operating decisions for safety and efficiency i.e. snow clearance, de-icing, grass-cutting, re-fueling etc.
Aerodrome Meteorological Stations
Sharing of observations to improve the accuracy and quality of forecasts.