Definition
An unscheduled in-flight weather advisory issued by an Air Route Traffic Control Center (ARTCC) meteorologist to alert pilots and controllers to existing or anticipated adverse weather conditions within the next two hours that may affect the safety of flight. A Center Weather Advisory (CWA) supplements the broader, scheduled weather products such as AIRMETs and SIGMETs by addressing conditions specific to that Center's airspace.
Plain English
A short-notice weather warning issued by the meteorologist working at an Air Traffic Control Center, describing bad weather happening now or expected within the next couple of hours in that Center's area.
Context Anchor
Seen in aviation weather information and air traffic control weather updates when conditions such as thunderstorms, rough air, ice buildup, or very low visibility may affect flight operations soon.
Derivation
Center' refers to the Air Route Traffic Control Center, the ATC facility that handles enroute traffic over a large region. 'Advisory' comes from the Latin advisare, 'to consider or give counsel.' Together, the term names a piece of weather counsel issued by, and tailored to, that Center's airspace.
Why Pilots Care
These advisories directly affect route selection, altitude choice, and go/no-go decisions to avoid hazardous weather.
Grounding Statement
If one of these advisories applies to your route, treat it as a current operating concern rather than background weather information.
Intuition Check
Do not read “advisory” as casual or optional advice. Here it means an official aviation weather alert that should be considered in flight decisions.
Example Sentence 1
Center issued a CWA for a line of thunderstorms building west of our route, so we requested a deviation thirty miles south.
Example Sentence 2
A Weather Advisory for moderate icing was in effect, so the crew decided to remain below the freezing level.