Definition
An unscheduled in-flight aviation weather advisory issued by the National Weather Service to alert pilots of the actual occurrence or imminent development of severe weather phenomena, including severe thunderstorms with surface winds of 50 knots or greater, hail three-quarters of an inch or larger in diameter, or tornadoes. The AWN replaced the former Severe Weather Watch Bulletin (WW) and identifies the area, time period, and type of severe weather expected.
Plain English
A severe-weather alert sent to pilots that says: dangerous thunderstorms, large hail, or tornadoes are happening right now or about to happen in this area, between these times.
Context Anchor
Seen in aviation weather information when severe convective weather is possible or already being watched over a region.
Derivation
"Watch" in weather terminology means conditions are favorable for severe weather to develop — distinct from a "warning," which means severe weather is occurring or imminent at a specific location. The AWN is the aviation-tailored version of that watch product.
Why Pilots Care
It gives early notice of areas where flight conditions may rapidly deteriorate, allowing route adjustments or delays before departure.
Grounding Statement
If a wide area has conditions that could produce severe thunderstorms or tornadoes, this message tells aviation users where and when that risk exists.
Intuition Check
Do not read “watch” as meaning the severe weather is already happening at your exact location. In this use, it means conditions are favorable for severe weather within the watch area.
Example Sentence 1
During preflight, the briefer noted an active Aviation Watch Notification Message covering the planned route, prompting the pilot to delay departure until the line of storms moved east.
Example Sentence 2
Dispatch forwarded the Aviation Watch Notification Message to the crew so they could select an alternate airport outside the watch boundaries.