What is a Center Weather Advisory?
A Center Weather Advisory (CWA) is a weather warning given to pilots and air traffic controllers, advising hazardous weather conditions meeting or approaching national advisory criteria over a large area. Keep in mind that CWA's are a product of a "center". You can find information on any Center Weather Advisories issued on aviationweather.gov.
Now you are probably wondering what a "center" is?
An Air Route Traffic Control Center (ARTCC), also referred to as "Center", which are large areas of controlled airspace. A couple of examples are:
Los Angeles Center (ZLA)
Denver Center (ZDV)
Boston Center (ZBW)
Center Weather Advisories are valid for up to 2 hours and may include forecasts of conditions to be expected within 2 hours. Since, CWA's are short lived they should not be used for flight planning.
CWA for Miami Center (ZMA)
A CWA is issued when any of the following weather conditions occur:
Conditions meeting convective SIGMET criteria
Icing - moderate or greater
Turbulence - moderate or greater
Conditions at or approaching Low IFR (LIFR)
Surface winds/gusts greater than 30 knots
Low Level Wind Shear (LLWS) surface - 2,000 feet
Volcanic ash, dust storms, or sandstorms
An upgrade to an AIRMET, SIGMET or Convective SIGMET
Upgrade a thunderstorm advisory, including severe thunderstorms
When a hazard has grown significantly outside of the boundary defined by the Aviation Weather Center (AWC) or Alaska Aviation Weather Unit (AAWU) advisory.
Another thing you may find on the CWA page of aviationweather.gov, is an MIS (Meteorological Impact Statement). This are used for ATC planning purposes more for airliners, which travel across multi states or the country, and not so much for general aviation pilots. MIS's are still good information.
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