What is the primary distinction between a SIGMET and an AIRMET?
Why →
AIRMETs cover conditions primarily hazardous to light aircraft and limited-capability aircraft. SIGMETs cover severe or extreme conditions hazardous to ALL aircraft, including heavy jets. SIGMET conditions include severe/extreme turbulence, severe icing, dust/sandstorms reducing visibility below 3 miles, and volcanic ash.The trap →
Convective SIGMETs (WST) are a separate product for convective weather. Standard SIGMETs cover non-convective severe hazards. The AIRMET/SIGMET distinction is about severity, not the issuing authority (both come from the NWS Aviation Weather Center).SOURCE → FAA Aviation Weather Services / PHAK Chapter 13CHECKED APR 21ACS III.A.K1MED