What conditions warrant the issuance of a Convective SIGMET?

The issuance of a Convective SIGMET is specifically linked to severe convective weather phenomena. This includes situations where thunderstorms are present, especially those capable of producing tornadoes and large hail, specifically hail that is greater than 3/4 of an inch. These conditions indicate significant instability in the atmosphere and potential for severe weather that can affect flight safety.

When thunderstorms are associated with severe turbulence, wind shear, or conditions likely to cause hazardous conditions for aircraft, it prompts the issuance of a Convective SIGMET. This advisory is crucial for pilots as it serves to warn them about potentially dangerous weather that is specifically related to convective activity.

Other options listed do not meet the criteria for a Convective SIGMET. Conditions like clear weather with low visibility and calm winds or high temperatures with fog and light rain do not indicate severe convection and therefore would not warrant a Convective SIGMET. Additionally, while snowstorms and icy conditions are serious, they fall under different types of advisories and not within the realm of convective weather phenomena, which is the primary focus of a Convective SIGMET.