What are CWAs? These advisories give warnings to ATC and pilots about hazardous weather over very large areas. CWAs are valid for up to 2 hours and may include forecasts of conditions expected to begin within 2 hours.
A CWA is issued when any of the following conditions occur:
Conditions meeting Convective SIGMET criteria
Icing – moderate or greater
Turbulence – moderate or greater
Heavy and extreme precipitation
Conditions at or approaching low IFR (LIFR)
Surface wind gust at or above 30kts
LLWS (low-level wind shear, surface to 2,000’agl)
Volcanic ash, duststorms, or sandstorms
When a hazard has grown significantly outside of the boundary defined by the AWC (aviation weather center) or AAWU (Alaska aviation weather unit) advisory
To upgrade a thunderstorm advisory to include severe thunderstorms
To upgrade an AIRMET to include isolated severe turbulence or icing
To define a line of thunderstorms within a larger area covered by the AWC or AAWU advisory
Anything that in the judgment of the CWSU forecaster will add value to an existing advisory
You are flying along getting flight following from approach. You hear the audio clip below on frequency (click below to listen). This prompts you to request a frequency change momentarily to contact flight service and receive an updated weather briefing in flight to ensure the severe weather described is not moving towards your route of flight.