Definition
A Terminal Aerodrome Forecast (TAF) is an official weather forecast issued by the National Weather Service for the airspace within a five statute mile radius of an airport. It describes expected surface wind, visibility, weather phenomena, and cloud conditions over a 24- or 30-hour period, and is updated four times daily (typically 0000Z, 0600Z, 1200Z, and 1800Z).
Plain English
A short weather forecast for the area right around a specific airport, telling pilots what wind, visibility, weather, and clouds to expect there over roughly the next day.
Context Anchor
Pilots use TAFs during preflight planning to judge expected weather at the departure airport, destination airport, and possible alternate airports.
Derivation
Terminal' here refers to the airport area (the terminal end of a flight, not a building). 'Aerodrome' is an older British-origin word for an airport, still used internationally. 'Forecast' simply means a prediction. So the name describes exactly what it is: a weather prediction for an airport area.
Why Pilots Care
TAFs help pilots decide whether conditions will allow a safe landing, whether an alternate airport is required, and how much extra fuel to carry.
Grounding Statement
Think of a TAF as the airport-specific weather prediction a pilot checks before deciding how the next part of the flight is likely to go.
Intuition Check
Do not read terminal as the passenger terminal building. In TAF, terminal means the airport area, and forecast means expected future weather rather than current weather.
Example Sentence 1
During preflight planning, she pulled up the TAF for her destination and saw that visibility was forecast to drop below three miles around her planned arrival time.
Example Sentence 2
The updated TAF showed improving visibility after 1800Z, allowing the flight to proceed as scheduled.