Definition
An in-flight weather message issued by air traffic control or a flight service station to alert pilots to actual or forecast weather conditions that may affect the safety of flight, such as thunderstorms, turbulence, icing, low ceilings, or reduced visibility.
Plain English
A heads-up about weather that could be a problem for your flight, passed along by ATC or Flight Service.
Context Anchor
Pilots encounter Weather Advisories during preflight weather checks, in weather briefings, and sometimes through updates passed by a controller while a flight is in progress.
Derivation
From Latin 'advisare,' to consider or take counsel. An advisory is information offered to help you decide — not an order. The word signals that the weather information is being given so the pilot can act on it, but the decision remains the pilot's.
Why Pilots Care
Allows pilots to anticipate and respond to conditions that could compromise safety, such as by altering route or altitude.
Intuition Check
Do not read “advisory” as casual advice that can be ignored. In this context, it is an official aviation weather notice about conditions that may affect safety.
Example Sentence 1
Center issued a weather advisory for a line of thunderstorms forming along our route fifty miles ahead.
Example Sentence 2
ATC relayed a weather advisory for icing in the area, so the crew activated the anti-ice systems early.