What does a convective SIGMET indicate?

A convective SIGMET is specifically designed to provide information about significant weather phenomena associated with convective activity, which includes thunderstorms. The key features of a convective SIGMET include the presence of severe thunderstorms, which can bring hazards such as hail larger than ¾ inch, tornadoes, surface winds of 50 knots or more, as well as areas of turbulence or severe non-thunderstorm turbulence. This concentrated focus on severe weather conditions makes option B the most accurate description of what a convective SIGMET indicates.

The other options, in contrast, do not reflect the nature of a convective SIGMET. Heavy rain without lightning does not capture the severe weather aspect that convective SIGMETs address. Clear weather with no significant events is fundamentally outside the scope of a SIGMET, as these are issued specifically when there are significant weather events to report. A low-level wind shear advisory pertains to wind conditions that may affect performance during takeoff or landing, which is unrelated to the severe thunderstorm conditions that convective SIGMETs provide information about.