Description

SIGMET information is information issued by a meteorological watch office concerning the occurrence or expected occurrence of specified en-route weather phenomena which may affect the safety of aircraft operations. (ICAO Annex 3: Meteorology)

A SIGMET gives a concise description of the phenomena in abbreviated plain language.

The following are examples of weather phenomena that may be described in a SIGMET:

• Thunderstorms
• Cyclones (Tropical Revolving Storms)
• Severe turbulence
• Severe icing
• Severe Mountain Waves
• Dust or Sand Storms
• Volcanic Ash

Further Reading

• ICAO Annex 3 Chapter 7
• Doc 8896 - Manual of Aeronautical Meteorological Practice, 9th edition, 2011
• AC 00-45H - Aviation Weather Services, FAA, 14 Nov 2016.