How does Convective SIGMET differ from a general SIGMET?

• A. Convective SIGMET specifically warns of convective weather such as severe thunderstorms.
• B. Convective SIGMET warns of volcanic ash clouds.
• C. Convective SIGMET applies to icing conditions.
• D. Convective SIGMET is a forecast issued every six hours.

Answer: (D)

The main idea is that convective SIGMETs are issued for weather produced by convection—thunderstorms and their hazards—whereas general SIGMETs cover significant weather phenomena not tied to convection, such as icing, turbulence, volcanic ash, or dust.

This is why the statement that convective SIGMET specifically warns of convective weather like severe thunderstorms best captures the difference. Convective SIGMETs are issued as needed when convective activity is present or expected, and they typically have a shorter valid period, reflecting the rapid changes often seen with thunderstorms. General SIGMETs, on the other hand, cover non-convective hazards and are issued on a broader, less frequent schedule with longer validity. The option that mentions a fixed six-hour issuance schedule does not describe how convective SIGMETs are produced.