Iowa Severe Severe Thunderstorm Watch | Effective 08/18/2026 16:50

Headline: 
Severe Thunderstorm Watch issued August 18 at 6:50PM CDT until August 19 at 12:00AM CDT by NWS Des Moines IA
Event: 
Severe Thunderstorm Watch
Urgency: 
Future
Effective: 
August 18, 2026 - 4:50pm
Expires: 
August 18, 2026 - 10:00pm
Description: 
THE NATIONAL WEATHER SERVICE HAS ISSUED SEVERE THUNDERSTORM WATCH 597 IN EFFECT UNTIL MIDNIGHT CDT TONIGHT FOR THE FOLLOWING AREAS IN IOWA THIS WATCH INCLUDES 17 COUNTIES IN CENTRAL IOWA GRUNDY HAMILTON HARDIN WEBSTER IN NORTH CENTRAL IOWA BUTLER CERRO GORDO FRANKLIN HANCOCK HUMBOLDT KOSSUTH WRIGHT IN NORTHEAST IOWA BLACK HAWK BREMER IN NORTHWEST IOWA EMMET PALO ALTO POCAHONTAS IN WEST CENTRAL IOWA CALHOUN THIS INCLUDES THE CITIES OF ACKLEY, ALGONA, ALLISON, APLINGTON, BELMOND, BRITT, CEDAR FALLS, CLARION, CLARKSVILLE, CLEAR LAKE, CONRAD, DIKE, DUMONT, EAGLE GROVE, ELDORA, EMMETSBURG, ESTHERVILLE, FONDA, FORT DODGE, GARNER, GILMORE CITY, GREENE, GRUNDY CENTER, HAMPTON, HUMBOLDT, IOWA FALLS, KANAWHA, LAKE CITY, LAURENS, MANSON, MASON CITY, PARKERSBURG, POCAHONTAS, POMEROY, REINBECK, ROCKWELL CITY, ROLFE, SHELL ROCK, WATERLOO, WAVERLY, WEBSTER CITY, AND WELLSBURG. * PRIMARY THREATS INCLUDE... SCATTERED LARGE HAIL AND ISOLATED VERY LARGE HAIL EVENTS TO 2 INCHES IN DIAMETER POSSIBLE. SCATTERED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE. PROBABILITY TABLE: PROB OF 2 OR MORE TORNADOES : = 2 INCHES : 30% PROB OF 6 OR MORE COMBINED SEVERE HAIL/WIND EVENTS : 70% MEAN STORM MOTION /MPH/ : SE 30
Area Description: 
Black Hawk, IA; Bremer, IA; Butler, IA; Calhoun, IA; Cerro Gordo, IA; Emmet, IA; Franklin, IA; Grundy, IA; Hamilton, IA; Hancock, IA; Hardin, IA; Humboldt, IA; Kossuth, IA; Palo Alto, IA; Pocahontas, IA; Webster, IA; Wright, IA
Forcast Office: 
NWS Des Moines IA
Sender: 
w-nws.webmaster@noaa.gov