Definition
A Terminal Aerodrome Forecast that has been officially revised and reissued by the forecasting office because conditions have changed, or are expected to change, significantly enough that the original forecast is no longer accurate. The amended forecast replaces the previous TAF for that airport and remains valid until the end of the original forecast period or until further amended.
Plain English
An updated airport forecast issued when the weather is no longer doing what the earlier forecast said it would. The new version replaces the old one.
Context Anchor
Seen at the beginning of a TAF in aviation weather briefings, flight planning tools, and FAA weather products.
Derivation
AMD is short for 'amended,' from the Latin emendare, meaning 'to correct' or 'to free from fault.' The label signals that the forecast has been corrected because the original no longer reflects expected conditions.
Why Pilots Care
Pilots rely on the most current forecast to make safe go/no-go decisions and adjust arrival planning.
Intuition Check
Do not read AMD as a minor note or optional add-on. It means the forecast was changed, and the amended forecast is the one to use.
Example Sentence 1
During the preflight briefing, the pilot noticed a TAF AMD had been issued for the destination, lowering the forecast ceilings and prompting a review of the planned alternate.
Example Sentence 2
Before departure we reviewed the latest TAF AMD to confirm the expected wind at our estimated arrival time.