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Inmeteorology andaviation,terminal aerodrome forecast (TAF) is a format for reportingweather forecast information,[1] particularly as it relates to aviation.
TAFs complement and use similar encoding toMETAR reports. They are produced by a human forecaster based on the ground. For this reason, there are considerably fewer TAF locations than there are airports for which METARs are available. TAFs can be more accurate thannumerical weather forecasts, since they take into account local, small-scale, geographic effects.
Today, according to the advancement of technology in civil aviation, the TAF is sent asIWXXM model.[2]
In the United States, TAFs are issued for nearly 700 airports. Most of them provide a 24-hour forecast for the airport, with some major airports forecasting for 30 hours into the future.[3] TAFs are issued at least four times a day, every six hours, for major civil airfields: 0000, 0600, 1200 and 1800 UTC,[4] and generally apply to a 24- or 30-hour period, and an area within approximately fivestatute miles (8.0 km) (or 5 nautical miles (9.3 km) in Canada) from the center of an airport runway complex. TAFs are issued every three hours for military airfields and some civil airfields and cover a period ranging from 3 hours to 30 hours.
Different countries use different change criteria for their weather groups. In the United Kingdom, TAFs for military airfields usecolour states as one of the change criteria. Civil airfields in the UK use slightly different criteria.
If information sources, such as surface observations, are missing, unreliable, or not complete, forecasterswillappend AMD NOT SKED to the end of a TAF. This code indicates the forecasterhas enough data, using the total observation concept, to issue a forecast, but will not provide updates. Thisallows airport operations to continue using a valid TAF. In rare situations where observations have been missing for extended periods of time (i.e., more than one TAF cycle of 6 hours) and the total observation concept cannot provide sufficient information, the TAF may be suspended by the use ofNIL TAF.[5]
In the United States, the weather forecasters responsible for the TAFs in their respective areas are located within one of the122 Weather Forecast Offices operated by the United States'National Weather Service. In contrast, atrend type forecast (TTF), which is similar to a TAF, is always produced by a person on-site where the TTF applies. In the United Kingdom, most TAFs for military airfields are produced locally, however TAFs for civil airfields are produced at theMet Office headquarters inExeter.
TheUnited States Air Force employs active duty enlisted personnel as TAF writers. Air Force weather personnel are responsible for providing weather support for all Air Force and Army operations.
This TAF example of a 30-hour TAF was released on November 5, 2008, at 1730UTC:
TAF KXYZ 051730Z 0518/0624 31008KT 3SM -SHRA BKN020 FM052300 30006KT 5SM -SHRA OVC030 PROB30 0604/0606 VRB20G35KT 1SM TSRA BKN015CB FM060600 25010KT 4SM -SHRA OVC050 TEMPO 0608/0611 2SM -SHRA OVC030 RMK NXT FCST BY 00Z=
The first line contains identification and validity times.
TAF AMD) or a corrected forecast (TAF COR)[3]The remainder of the first line contain the initial forecast conditions. Variations of the codes used for various weather conditions are many.[6]
Each line beginning withFM indicates a rapid change in the weather over a period of less than an hour.
The final line is for errata, comments, and remarks.
This article incorporates text from this source, which is in thepublic domain.