Alert archive / Iowa / Severe Thunderstorm Warnings in 2026

Severe Thunderstorm Warning 237, NWS Des Moines, IA

June 17, 2026Marshall County, Poweshiek County, Tama County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Jun 17, 2026, 5:49 AM CDT for Marshall County, Poweshiek County, Tama County, Iowa. It was in force for 56 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Jun 17, 2026, 5:49 AM CDT (10:49 UTC)
Expired: Jun 17, 2026, 6:45 AM CDT
In force: 56 min
Issued by: NWS Des Moines, IA
Area: Storm-based polygon
Damage threat: Destructive
Hail: 0.75 in
Wind: 90.0 mph

Counties Marshall County, IA, Poweshiek County, IA, Tama County, IA

The radar

The Des Moines radar (KDMX), 89 km from the middle of the area, began a volume at 10:53 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Jun 17, 3:55 AM CDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 10.8 hours before the alert went out and 314 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 2278 m above ground
0-6 km bulk shear: 45 kt
0-1 km storm-relative helicity: 55 m²/s²
0-3 km storm-relative helicity: 220 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Des Moines, IA wrote its last area forecast discussion before this severe thunderstorm warning went out at Jun 17, 1:34 AM CDT, 4 hours 15 minutes earlier.

Area forecast discussion, Jun 17, 1:34 AM CDT, 4 hours 15 minutes before

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Hazardous weather outlook, Jun 16, 3:15 PM CDT, 14 hours 34 minutes before

Hazardous Weather Outlook
National Weather Service Des Moines IA
315 PM CDT Tue Jun 16 2026

IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-
081>086-092>097-172015-
Emmet-Kossuth-Winnebago-Worth-Palo Alto-Hancock-Cerro Gordo-
Pocahontas-Humboldt-Wright-Franklin-Butler-Bremer-Sac-Calhoun-
Webster-Hamilton-Hardin-Grundy-Black Hawk-Crawford-Carroll-Greene-
Boone-Story-Marshall-Tama-Audubon-Guthrie-Dallas-Polk-Jasper-
Poweshiek-Cass-Adair-Madison-Warren-Marion-Mahaska-Adams-Union-
Clarke-Lucas-Monroe-Wapello-Taylor-Ringgold-Decatur-Wayne-
Appanoose-Davis-
315 PM CDT Tue Jun 16 2026

This Hazardous Weather Outlook is for portions of central Iowa.

.DAY ONE...This afternoon and tonight

Thunderstorms are expected late tonight (early Wednesday
morning) in north central Iowa moving into eastern Iowa through
the morning Wednesday. These storms may become severe with large
hail and damaging winds the main threats.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

Thunderstorms may redevelop Wednesday afternoon across the eastern
half of Iowa. Very large hail, damaging winds, and a few tornadoes
are possible.

Strong winds are expected on Wednesday ahead of the storms in
southern Iowa and behind the storms in northern to portions of
central and eastern Iowa with gusts to 30-40 mph or more at
times.

.SPOTTER INFORMATION STATEMENT...

Any storm reports Wednesday are appreciated.

In the hours before

Local storm report, Jun 17, 4:58 AM CDT, 51 minutes before

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Local storm report, Jun 17, 5:03 AM CDT, 46 minutes before

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Local storm report, Jun 17, 5:11 AM CDT, 38 minutes before

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Local storm report, Jun 17, 5:27 AM CDT, 22 minutes before

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Local storm report, Jun 17, 5:32 AM CDT, 17 minutes before

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Local storm report, Jun 17, 5:36 AM CDT, 13 minutes before

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The office that day

Everything else NWS Des Moines, IA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 17, 12:19 AM CDT	Wind Advisory	DMX	Appanoose, Calhoun, Crawford, Davis, Decatur, Emmet and 6 more	20 hr
Jun 17, 3:53 AM CDT	Severe Thunderstorm Warning	DMX	Calhoun, Pocahontas, Sac	52 min
Jun 17, 4:31 AM CDT	Severe Thunderstorm Warning	DMX	Boone, Calhoun, Greene, Hamilton, Webster	44 min
Jun 17, 4:52 AM CDT	Severe Thunderstorm Warning Considerable damage threat	DMX	Boone, Hamilton, Hardin, Marshall, Story	53 min
Jun 17, 5:13 AM CDT	Severe Thunderstorm Warning	DMX	Boone, Greene, Hamilton, Webster	32 min
Jun 17, 5:32 AM CDT	Severe Thunderstorm Warning Considerable damage threat	DMX	Jasper, Marshall, Story, Tama	43 min
Jun 17, 5:34 AM CDT	Severe Thunderstorm Warning	DMX	Boone, Jasper, Marshall, Polk, Story	41 min
Jun 17, 5:43 AM CDT	Severe Thunderstorm Warning	DMX	Grundy, Marshall, Tama	47 min
Jun 17, 6:08 AM CDT	Severe Thunderstorm Warning	DMX	Jasper, Mahaska, Marshall, Poweshiek	67 min
Jun 17, 6:50 AM CDT	Severe Thunderstorm Warning	DMX	Jasper, Mahaska, Marion, Poweshiek	55 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2026 Every severe thunderstorm warning in 2026

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.