Definition
A continuous recorded broadcast of hazardous weather information transmitted over selected VOR frequencies, alerting pilots in flight to conditions such as severe thunderstorms, turbulence, icing, low ceilings, and other significant weather hazards within the broadcast area.
Plain English
A recorded weather warning that pilots can listen to over a navigation radio while flying, telling them about dangerous weather nearby.
Context Anchor
Seen in FAA acronym lists, weather briefing material, and aviation weather discussions when hazardous weather information is being identified or passed to pilots.
Derivation
The name is descriptive: it advises pilots, in flight, about hazardous weather. The 'service' the acronym implies is the continuous broadcast system that delivers it.
Why Pilots Care
Gives pilots immediate information needed to divert or change altitude before encountering weather that could lead to loss of aircraft control.
Intuition Check
Do not read advisory as casual advice here. In aviation weather use, an advisory is an official notice that deserves immediate attention because it may affect safety.
Example Sentence 1
Before pressing on toward the building cloud line, she tuned the VOR and listened to the HWAS broadcast for any active thunderstorm advisories.
Example Sentence 2
After hearing an HWAS report of moderate icing, the crew climbed to a higher altitude to remain in clear air.