5/19/22
AIM
boundaries. Bulletins are issued hourly at H+55.
Special bulletins are issued at any time as required
and updated at H+55. If no criteria meeting
convective SIGMET requirements are observed or
forecasted, the message “CONVECTIVE SIGMET...
NONE” will be issued for each area at H+55.
Individual convective SIGMETs for each area (W, C,
E) are numbered sequentially from number one each
day, beginning at 00Z. A convective SIGMET for a
continuing phenomenon will be reissued every hour
at H+55 with a new number. The text of the bulletin
consists of either an observation and a forecast or just
a forecast. The forecast is valid for up to 2 hours.
EXAMPLE
−
CONVECTIVE SIGMET 44C
VALID UNTIL 1455Z
AR TX OK
FROM 40NE ADM-40ESE MLC-10W TXK-50WNW
LFK-40ENE SJT-40NE ADM
AREA TS MOV FROM 26025KT. TOPS ABV FL450.
OUTLOOK VALID 061455-061855
FROM 60WSW OKC-MLC-40N TXK-40WSW
IGB-VUZ-MGM-HRV-60S BTR-40N
IAH-60SW SJT-40ENE LBB-60WSW OKC
WST ISSUANCES EXPD. REFER TO MOST RECENT
ACUS01 KWNS FROM STORM PREDICTION CENTER
FOR SYNOPSIS AND METEOROLOGICAL DETAILS
FIG 7
−
1
−
4
SIGMET and AIRMET Locations
−
Conterminous United States
Meteorology
7
−
1
−
13