Alert archive / Iowa / Severe Thunderstorm Warnings in 2025

Severe Thunderstorm Warning 211, NWS Des Moines, IA

August 15, 2025Calhoun County, Pocahontas County, Sac County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Aug 15, 2025, 12:21 PM CDT for Calhoun County, Pocahontas County, Sac County, Iowa. It was in force for 39 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
Aug 15, 2025, 12:21 PM CDT (17:21 UTC)
Expired
Aug 15, 2025, 1:00 PM CDT
In force
39 min
Issued by
NWS Des Moines, IA
Area
Storm-based polygon
Damage threat
Considerable
Hail
1.75 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 17:23 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 nearest sounding before it

Minneapolis, MN (KMPX), launched 12:00Z, 5.4 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-pSkew-T log-p diagram, Minneapolis, MN at 12:00Z on 2025-08-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1154 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Minneapolis, MN at 12:00Z on 2025-08-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 349 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
1154 J/kg
Mixed-layer CIN
-170 J/kg
Mixed-layer LCL
833 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
349 m²/s²
0-3 km storm-relative helicity
265 m²/s²
Significant tornado parameter
0.0
Supercell composite
8.4

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 Aug 15, 6:13 AM CDT, 6 hours 8 minutes earlier.

Area forecast discussion, Aug 15, 6:13 AM CDT, 6 hours 8 minutes before
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Hazardous weather outlook, Aug 15, 6:21 AM CDT, 6 hours before
Hazardous Weather Outlook
National Weather Service Des Moines IA
621 AM CDT Fri Aug 15 2025

IAZ004>007-015>017-023>028-033>039-044>050-057>062-072>075-086-
161130-
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-Madison-Warren-Marion-Mahaska-Wapello-
621 AM CDT Fri Aug 15 2025

This Hazardous Weather Outlook is for portions of central Iowa.

.DAY ONE...Today and tonight

Scattered showers and storms possible throughout the day Friday,
especially in the afternoon and evening. There is a Marginal Risk
for severe weather across northern Iowa. Damaging winds will be
the primary threat.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

Intermittent storm chances continue through the weekend, mainly
over northern Iowa along the Iowa/Minnesota border.

The weekend will be hot with heat indices over 100 degrees
possible.

.SPOTTER INFORMATION STATEMENT...

Spotters may be needed in northern Iowa Today.

IAZ070-071-081>085-092>097-161130-
Cass-Adair-Adams-Union-Clarke-Lucas-Monroe-Taylor-Ringgold-
Decatur-Wayne-Appanoose-Davis-
621 AM CDT Fri Aug 15 2025

This Hazardous Weather Outlook is for portions of central Iowa.

.DAY ONE...Today and tonight

A Heat Advisory is in effect for the area. Please refer to the
National Weather Service website at weather.gov/desmoines for
further details.

Scattered showers and non-severe storms southwest in the morning.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

The weekend will be hot with heat indices over 100 degrees
possible.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated.

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 15, 12:50 PM CDTSevere Thunderstorm WarningDMXCalhoun, Hamilton, Hancock, Humboldt, Kossuth, Palo Alto and 5 more40 min
Aug 15, 2:00 PM CDTSevere Thunderstorm WarningDMXCerro Gordo, Franklin, Hancock, Wright45 min
Aug 15, 2:27 PM CDTSevere Thunderstorm WarningDMXCerro Gordo33 min
Aug 15, 2:32 PM CDTSevere Thunderstorm WarningDMXButler28 min
Aug 15, 2:51 PM CDTHeat AdvisoryDMXAdair, Adams, Appanoose, Audubon, Black Hawk, Boone and 45 more29 hr
Aug 15, 2:59 PM CDTSevere Thunderstorm WarningDMXBremer, Butler61 min
Aug 15, 3:36 PM CDTSevere Thunderstorm WarningDMXButler, Franklin, Grundy, Hamilton, Hardin, Marshall and 2 more39 min
Aug 15, 4:15 PM CDTSevere Thunderstorm WarningDMXGrundy, Hardin, Marshall, Tama45 min
Aug 15, 4:54 PM CDTSevere Thunderstorm WarningDMXBlack Hawk, Grundy, Marshall, Poweshiek, Tama51 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2025Every severe thunderstorm warning in 2025

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.