Question

What will a convective SIGMET be issued for?

1) Squall line thunderstorms
2) Visibility less than 3 miles
3) Surface winds greater than 40 knots

Answer 1

A convective SIGMET is issued for hazardous weather conditions including squall line thunderstorms, embedded thunderstorms, and tornadoes, which affect aviation flight safety.

Step-by-step explanation:

A convective SIGMET, or Significant Meteorological Information, is issued to warn pilots of certain hazardous weather conditions that affect flight safety. Among the conditions for which a convective SIGMET will be issued are:

1. Squall line thunderstorms which are intense, narrow bands of severe thunderstorms that can be accompanied by heavy precipitation, high winds, and dangerous lightning.
2. Embedded thunderstorms which are severe thunderstorms that are surrounded by heavy cloud cover, making them harder to detect visually.
3. Tornadoes which are violently rotating columns of air that are in contact with both the cloud base and the surface.

Note that although reduced visibility and high surface winds can be associated with severe weather conditions, they are not in themselves reasons for the issuance of a convective SIGMET unless related to the convective phenomena like thunderstorms or tornadoes.