Plain English Meaning

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.

Full 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.

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.