⚠️ Severe Thunderstorm Watch – 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 – Tuesday, August 18, 2026

Severe Thunderstorm Watch issued August 18 at 6:50PM CDT until August 19 at 12:00AM CDT by NWS Des Moines IA

Details

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 : <05%
PROB OF 1 OR MORE STRONG /EF2-EF5/ TORNADOES : <02%
PROB OF 10 OR MORE SEVERE WIND EVENTS : 40%
PROB OF 1 OR MORE WIND EVENTS >= 75 MPH : 20%
PROB OF 10 OR MORE SEVERE HAIL EVENTS : 40%
PROB OF 1 OR MORE HAIL EVENTS >= 2 INCHES : 30%
PROB OF 6 OR MORE COMBINED SEVERE HAIL/WIND EVENTS : 70%
MEAN STORM MOTION /MPH/ : SE 30

This alert was automatically posted by SkyGuard, MWSC’s severe weather alerting system. Source: National Weather Service.