What are issued for thunderstorms , tornadoes , and hail 3/4 inch or larger , but do not include references to all weather associated with thunderstorms ?

• A. TAF
• B. PIREP
• C. WST
• D. SIGMET

Answer: (C)

Hazardous convective weather is what this product communicates. WST, or Convective SIGMET, is issued to warn pilots and ATC about significant convective activity that could affect flight safety—specifically thunderstorms, tornadoes, and hail at least 3/4 inch in diameter. It focuses on the severe, travel-impacting aspects of storms, not every weather feature that might accompany thunderstorms like light rain or minor winds.

Other products serve different purposes: a forecast for conditions at a specific airport is provided by a TAF; a PIREP is a pilot’s live observation of weather encountered en route; and SIGMETs cover significant weather phenomena that aren’t tied to convection. So the convective SIGMET product is the correct choice for the hazards described.