SIGMET

[3] There are three main types of internationally recognized SIGMETs per ICAO:[4] This information is usually broadcast on the ATIS at ATC facilities, as well as over VOLMET stations.

helps denote the altitude that the phenomenon will be occurred, and can be expressed as [MOV XXX xx KT/KMH] if it is a moving front, the direction and rate of movement given as a compass direction (XXX, e.g. "N" or "WNW"), and the rate is given in KT (or KMH).

[FCST AT Z ] helps note where the front is expected to be at the end of the SIGMET's validity period.

If when the validity period is due to expire but the phenomenon is expected to persist, a new sequence number is added to the SIGMET to renew it.

[6]: 5 An en-route weather phenomenon in the U.S., issued by the Aviation Weather Center in Kansas City, MO on the 7th of August, at 16:55 UTC[10] This is a convective weather pattern in the central region of the contiguous U.S. with sequence number 83C That is valid until 18:55 UTC That covers Minnesota, Indiana, Wisconsin, Illinois, Iowa, and Lower Michigan flight regions A description of the area of the storm, where GRR (Grand Rapids, MI airport), GIJ (Niles, MI VORTAC), BDF (Bradford, IL VORTAC), IOW (Iowa City, IA airport), and DBQ (Dubuque, IA airport) are ConTrol Areas (CTAs).