Which weather advisory is issued for significant weather phenomena not related to thunderstorms?

• A. SIGMET
• B. AIRMET
• C. PIREP
• D. SPECI

Answer: (A)

The idea here is recognizing which advisory covers significant weather events that aren’t tied to thunderstorms. SIGMETs are issued for non-convective, substantial weather phenomena that can affect flight safety, such as severe icing not related to thunderstorms, severe turbulence not associated with convective storms, dust or sand storms reducing visibility to hazardous levels, volcanic ash clouds, and other conditions that could pose a risk to aircraft en route. They are intended for all aircraft and cover relatively large areas for several hours of validity.

In contrast, AIRMETs describe lighter, more widespread weather that remains a concern for smaller aircraft or longer overcast routes—things like moderate icing or turbulence, continuous but less intense conditions, or visibility and mountain obscuration at a lower severity. PIREPs are pilot reports of actual weather conditions, not advisory products issued to cover flight planning. SPECI is a special weather observation issued when a significant change is observed at a weather station, not a broad advisory product for ongoing significant weather phenomena.