Alert archive / Iowa / Severe Thunderstorm Warnings in 2026

Severe Thunderstorm Warning 129, NWS Des Moines, IA

May 15, 2026Calhoun County, Pocahontas County, Sac County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at May 15, 2026, 6:29 PM CDT for Calhoun County, Pocahontas County, Sac County, Iowa. It was in force for 46 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: May 15, 2026, 6:29 PM CDT (23:29 UTC)
Expired: May 15, 2026, 7:15 PM CDT
In force: 46 min
Issued by: NWS Des Moines, IA
Area: Storm-based polygon
Hail: 1.25 in
Wind: 60.0 mph

Counties Calhoun County, IA, Pocahontas County, IA, Sac County, IA

The radar

The Des Moines radar (KDMX), 124 km from the middle of the area, began a volume at 23:30 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
May 15, 5:16 PM CDT	Severe Thunderstorm Watch	SPC	8 hr

The nearest sounding before it

Minneapolis, MN (KMPX), launched 12:00Z, 11.5 hours before the alert went out and 279 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: 2176 m above ground
0-6 km bulk shear: 61 kt
0-1 km storm-relative helicity: 233 m²/s²
0-3 km storm-relative helicity: 291 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 May 15, 3:01 PM CDT, 3 hours 28 minutes earlier.

Area forecast discussion, May 15, 3:01 PM CDT, 3 hours 28 minutes before

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Hazardous weather outlook, May 15, 4:53 AM CDT, 13 hours 36 minutes before

Hazardous Weather Outlook
National Weather Service Des Moines IA
453 AM CDT Fri May 15 2026

IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-
081>086-092>097-161000-
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-
453 AM CDT Fri May 15 2026

This Hazardous Weather Outlook is for portions of central Iowa.

.DAY ONE...Today and tonight

There is an Enhanced Risk (level 3 of 5) for severe storms today.
All modes of severe storms are possible. Storms are expected to
develop in northern and western Iowa early this evening, moving
across central to eastern Iowa late overnight.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

An active weather pattern will be in place through at least
Monday, with chances for strong to severe thunderstorms at times
each day. However the details of timing, location, and hazard
types will be better determined in the coming days.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is possible at times Friday through Monday.

Hagenhoff

In the hours before

Local storm report, May 15, 6:03 PM CDT, 26 minutes before

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Local storm report, May 15, 6:05 PM CDT, 24 minutes before

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Local storm report, May 15, 6:09 PM CDT, 20 minutes before

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Local storm report, May 15, 6:28 PM CDT, 1 minute 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
May 15, 5:27 PM CDT	Severe Thunderstorm Warning	DMX	Emmet, Palo Alto	48 min
May 15, 5:54 PM CDT	Severe Thunderstorm Warning	DMX	Emmet, Kossuth	51 min
May 15, 6:14 PM CDT	Severe Thunderstorm Warning	DMX	Humboldt, Kossuth, Palo Alto, Pocahontas	24 min
May 15, 6:33 PM CDT	Severe Thunderstorm Warning Considerable damage threat	DMX	Hancock, Kossuth, Winnebago	57 min
May 15, 6:46 PM CDT	Severe Thunderstorm Warning Considerable damage threat	DMX	Calhoun, Humboldt, Pocahontas, Webster	44 min
May 15, 6:52 PM CDT	Severe Thunderstorm Warning Considerable damage threat	DMX	Adair, Adams, Cass, Ringgold, Taylor, Union	53 min
May 15, 6:55 PM CDT	Severe Thunderstorm Warning	DMX	Sac	50 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.