Plain English Meaning
Official warnings sent out during flight to tell pilots about weather that could be dangerous or important to know about right now.
Full Definition
In-flight messages issued by the National Weather Service to alert pilots of actual or forecast weather conditions that may affect the safety of flight. They include products such as AIRMETs, SIGMETs, Convective SIGMETs, and Center Weather Advisories, each covering specific hazards like turbulence, icing, thunderstorms, low visibility, or strong surface .