When is a TAF considered to be amended?

A Terminal Aerodrome Forecast (TAF) is a statement of expected weather conditions at an airport over a specified period of time, usually covering 24 or 30 hours. It is considered amended when significant changes in weather conditions warrant an update to the forecast. This may include changes in parameters such as wind direction and speed, visibility, cloud cover, or other relevant phenomena that could impact flight operations. Amending a TAF ensures that pilots and crews have the most current and accurate information to make informed decisions regarding their flight plans and safety.

The need for updates arises specifically due to changing weather conditions, which can occur due to various atmospheric shifts, developments in fronts, or other weather systems. By amending the TAF, aviation authorities provide vital information that could affect operations, enhancing safety and efficiency in air travel. This makes the choice concerning updates due to changing weather the correct context for when a TAF is considered amended.