⚠️ Severe Thunderstorm Warning – Black Hawk, IA; Bremer, IA; Butler, IA; Franklin, IA; Grundy, IA – Monday, July 20, 2026

Severe Thunderstorm Warning issued July 20 at 3:24PM CDT until July 20 at 4:30PM CDT by NWS Des Moines IA

Details

SVRDMX

The National Weather Service in Des Moines has issued a

* Severe Thunderstorm Warning for…
Northwestern Black Hawk County in northeastern Iowa…
Bremer County in northeastern Iowa…
Northeastern Franklin County in north central Iowa…
Northeastern Grundy County in central Iowa…
Butler County in north central Iowa…

* Until 430 PM CDT.

* At 324 PM CDT, a severe thunderstorm was located near Aredale, or
11 miles northwest of Allison, moving southeast at 40 mph.

HAZARD…70 mph wind gusts and quarter size hail.

SOURCE…Radar indicated.

IMPACT…Hail damage to vehicles is expected. Expect considerable
tree damage. Wind damage is also likely to mobile homes,
roofs, and outbuildings.

* Locations impacted include…
Waterloo, Cedar Falls, Waverly, Allison, Parkersburg, Denver,
Clarksville, Tripoli, Shell Rock, Dike, Greene, Waterloo Municipal
Airport, Uni-Dome And McLeod Center, Janesville, Readlyn, Dumont,
New Hartford, Plainfield, Stout, and Bristow.

Instructions

For your protection move to an interior room on the lowest floor of a
building.

Large hail, damaging wind, and continuous cloud to ground lightning
are occurring with this storm. Move indoors immediately. Lightning is
one of nature’s leading killers. Remember, if you can hear thunder,
you are close enough to be struck by lightning.

A Tornado Watch remains in effect until 1000 PM CDT for central,
north central and northeastern Iowa.

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