⚠️ Severe Thunderstorm Warning – Black Hawk, IA; Grundy, IA; Hardin, IA; Marshall, IA; Tama, IA – Monday, July 20, 2026

Severe Thunderstorm Warning issued July 20 at 3:56PM CDT until July 20 at 5:00PM CDT by NWS Des Moines IA

Details

SVRDMX

The National Weather Service in Des Moines has issued a

* Severe Thunderstorm Warning for…
Southeastern Hardin County in central Iowa…
Marshall County in central Iowa…
Southwestern Black Hawk County in northeastern Iowa…
Tama County in central Iowa…
Grundy County in central Iowa…

* Until 500 PM CDT.

* At 355 PM CDT, a severe thunderstorm was located over Ackley
Municipal Airport, or 13 miles northeast of Eldora, moving
southeast at 55 mph.

HAZARD…70 mph wind gusts and quarter size hail.

SOURCE…Emergency management.

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, Marshalltown, Eldora, Grundy Center, Toledo,
La Porte City, Hudson, Traer, Reinbeck, Dysart, Dike, Conrad,
Meskwaki Casino, Uni-Dome And McLeod Center, Gladbrook, Le Grand,
Melbourne, Wellsburg, and Garwin.

Instructions

Remain alert for a possible tornado! Tornadoes can develop quickly
from severe thunderstorms. If you spot a tornado go at once into the
basement or small central room in a sturdy structure.

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.