⚠️ Severe Thunderstorm Watch – Boone, IA; Clarke, IA; Dallas, IA; Grundy, IA; Hamilton, IA; Hardin, IA; Jasper, IA; Lucas, IA; Madison, IA; Mahaska, IA; Marion, IA; Marshall, IA; Monroe, IA; Polk, IA; Poweshiek, IA; Story, IA; Tama, IA; Wapello, IA; Warren, IA; Webster, IA – Thursday, August 13, 2026

Severe Thunderstorm Watch issued August 13 at 5:51AM CDT until August 13 at 11:00AM CDT by NWS Des Moines IA

Details

THE NATIONAL WEATHER SERVICE HAS ISSUED SEVERE THUNDERSTORM WATCH
581 IN EFFECT UNTIL 11 AM CDT THIS MORNING FOR THE FOLLOWING
AREAS

IN IOWA THIS WATCH INCLUDES 20 COUNTIES

IN CENTRAL IOWA

BOONE DALLAS GRUNDY
HAMILTON HARDIN JASPER
MARSHALL POLK POWESHIEK
STORY TAMA WEBSTER

IN SOUTH CENTRAL IOWA

CLARKE LUCAS MADISON
MAHASKA MARION MONROE
WARREN

IN SOUTHEAST IOWA

WAPELLO

THIS INCLUDES THE CITIES OF ACKLEY, ADEL, ALBIA, AMES, BOONE,
CARLISLE, CHARITON, CONRAD, DES MOINES, DIKE, DYSART, EARLHAM,
ELDORA, FORT DODGE, GLADBROOK, GRINNELL, GRUNDY CENTER,
INDIANOLA, IOWA FALLS, KNOXVILLE, MARSHALLTOWN, NEWTON, NORWALK,
OSCEOLA, OSKALOOSA, OTTUMWA, PELLA, PERRY, REINBECK, TAMA,
TOLEDO, TRAER, WAUKEE, WEBSTER CITY, WELLSBURG, AND WINTERSET.

* PRIMARY THREATS INCLUDE…

SCATTERED DAMAGING WINDS LIKELY WITH ISOLATED SIGNIFICANT GUSTS
TO 75 MPH POSSIBLE.
ISOLATED LARGE HAIL EVENTS TO 1 INCH IN DIAMETER POSSIBLE.
A TORNADO OR TWO POSSIBLE.

PROBABILITY TABLE:
PROB OF 2 OR MORE TORNADOES : 20%
PROB OF 1 OR MORE STRONG /EF2-EF5/ TORNADOES : 05%
PROB OF 10 OR MORE SEVERE WIND EVENTS : 60%
PROB OF 1 OR MORE WIND EVENTS >= 75 MPH : 30%
PROB OF 10 OR MORE SEVERE HAIL EVENTS : 20%
PROB OF 1 OR MORE HAIL EVENTS >= 2 INCHES : <05%
PROB OF 6 OR MORE COMBINED SEVERE HAIL/WIND EVENTS : 80%
MEAN STORM MOTION /MPH/ : E 50

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