⚠️ Severe Thunderstorm Warning – Boone, IA; Jasper, IA; Polk, IA; Story, IA – Monday, July 20, 2026

Severe Thunderstorm Warning issued July 20 at 6:47PM CDT until July 20 at 7:30PM CDT by NWS Des Moines IA

Details

SVRDMX

The National Weather Service in Des Moines has issued a

* Severe Thunderstorm Warning for…
Northern Polk County in central Iowa…
Southern Story County in central Iowa…
Northwestern Jasper County in central Iowa…
Southeastern Boone County in central Iowa…

* Until 730 PM CDT.

* At 646 PM CDT, severe thunderstorms were located along a line
extending from near Colo to Huxley to 4 miles northeast of Berkley,
moving southeast at 30 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…
Ames, Ankeny, Johnston, Altoona, Grimes, Nevada, Bondurant, Polk
City, Huxley, Saylorville, Madrid, Mitchellville, Slater, Granger,
Baxter, Saylorville Lake, Big Creek Lake, Maxwell, Cambridge, and
Elkhart.

This includes the following highways…
Interstate 35 between mile markers 90 and 111.
Interstate 80 between mile markers 145 and 149.

Instructions

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

A Tornado Watch remains in effect until 1000 PM CDT for central Iowa.

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