Final answer:
A Convective SIGMET (WST) is a weather advisory that warns pilots of hazardous thunderstorm conditions.
Step-by-step explanation:
A Convective SIGMET (WST) is a weather advisory issued to warn pilots of hazardous weather conditions related to thunderstorms. It is used to provide information on severe thunderstorms, tornadoes, and large hail that can pose a threat to aviation safety.
The WST acronym stands for 'Weather Significant to Aviation'. Convective SIGMETs are issued for the entire United States and are valid for two hours. They provide details on the location, movement, and severity of convective weather phenomena.
For example, a Convective SIGMET might state that severe thunderstorms are producing large hail and damaging winds in a specific area, with a description of the storm's movement and expected impacts on aviation.