What is a Convective SIGMET?

• A. A SIGMET specifically warning of convective weather such as severe thunderstorms.
• B. A SIGMET for volcanic ash clouds.
• C. A SIGMET for low visibility due to fog.
• D. A SIGMET for general weather advisories not tied to convection.

Answer: (A)

Convective SIGMETs are alerts issued for weather phenomena produced by convection, mainly thunderstorms, that can pose hazards to flight. They specifically warn about convective activity such as severe thunderstorms capable of producing damaging surface winds (typically 50 knots or more), large hail (0.75 inches or larger), or tornadoes, and they cover a defined area for a limited time to help pilots avoid dangerous convection. This is distinct from other SIGMETs, which address non-convective hazards like volcanic ash clouds or weather caused by fog or general weather phenomena not tied to convection. So the statement that a Convective SIGMET is a SIGMET specifically warning of convective weather such as severe thunderstorms is the right description.