Aero Academic
Aero Academic
A scheduled forecast of expected surface weather conditions at an airport, valid for a set period and covering a five-statute-mile radius.
A Terminal Aerodrome Forecast (TAF) is a concise forecast of the weather expected at an airport, typically covering a 24-to-30-hour period and issued four times a day. It uses the same coding conventions as a METAR (wind, visibility, weather, cloud layers) so a pilot who can decode one can decode the other.
A TAF covers a five-statute-mile radius of the center of the airport's runway complex — this is a frequently tested detail, since it is easy to assume it covers the whole local area. Change groups within a TAF, such as FM (from a specific time), TEMPO (temporary, expected for less than an hour at a time), and PROB30/PROB40 (probability of occurrence), describe how conditions are expected to evolve.
Because a TAF is a forecast, not an observation, it can be wrong, and pilots are expected to cross-check it against current METARs, AIRMETs, and SIGMETs before and during a flight rather than relying on it alone.