Alert archive / Iowa / Severe Thunderstorm Warnings in 2026

Severe Thunderstorm Warning 324, NWS Des Moines, IA

August 13, 2026Mahaska County, Wapello County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Aug 13, 2026, 8:48 AM CDT for Mahaska County, Wapello County, Iowa. It was in force for 42 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 13, 2026, 8:48 AM CDT (13:48 UTC)
Expired
Aug 13, 2026, 9:30 AM CDT
In force
42 min
Issued by
NWS Des Moines, IA
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Mahaska County, IA, Wapello County, IA

The radar

The Des Moines radar (KDMX), 117 km from the middle of the area, began a volume at 13:49 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.

IssuedProductOfficeLasted
Aug 13, 5:47 AM CDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 1.8 hours before the alert went out and 350 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, Lincoln, IL at 12:00Z on 2026-08-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 882 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, Lincoln, IL at 12:00Z on 2026-08-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 60 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
882 J/kg
Mixed-layer CIN
-129 J/kg
Mixed-layer LCL
746 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
60 m²/s²
0-3 km storm-relative helicity
144 m²/s²
Significant tornado parameter
0.0
Supercell composite
3.7

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 13, 6:52 AM CDT, 1 hour 56 minutes earlier.

Area forecast discussion, Aug 13, 6:52 AM CDT, 1 hour 56 minutes before
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Hazardous weather outlook, Aug 13, 7:46 AM CDT, 1 hour 2 minutes before
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In the hours before

Local storm report, Aug 13, 5:25 AM CDT, 3 hours 23 minutes before
Preliminary Local Storm Report
National Weather Service Des Moines IA
525 AM CDT Thu Aug 13 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0519 AM     Tstm Wnd Gst     7 SW Gray               41.77N 95.08W
08/13/2026  M66 MPH          Audubon            IA   Mesonet

            Measured from personal weather station.

&&

67
Local storm report, Aug 13, 5:33 AM CDT, 3 hours 15 minutes before
Preliminary Local Storm Report
National Weather Service Des Moines IA
533 AM CDT Thu Aug 13 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0529 AM     Tstm Wnd Gst     1 NW Audubon            41.73N 94.94W
08/13/2026  M64 MPH          Audubon            IA   Mesonet

            Measured from personal weather station.

&&

67
Local storm report, Aug 13, 6:49 AM CDT, 1 hour 59 minutes before
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<body>
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    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
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Local storm report, Aug 13, 6:58 AM CDT, 1 hour 50 minutes before
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<body>
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    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
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        The site you requested is temporarily down for maintenance or an unexpected outage.
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        Please try again in a few minutes.
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The office that day

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

IssuedProductOfficeCountiesLasted
Aug 13, 2:53 AM CDTFlood WatchDMXAdair, Adams, Appanoose, Audubon, Black Hawk, Boone and 38 more55 hr
Aug 13, 4:29 AM CDTSevere Thunderstorm WarningDMXCrawford46 min
Aug 13, 4:44 AM CDTTornado WarningDMXCarroll, Crawford31 min
Aug 13, 5:09 AM CDTSevere Thunderstorm WarningDMXAudubon, Carroll, Crawford, Greene, Guthrie51 min
Aug 13, 5:30 AM CDTTornado WarningDMXCarroll30 min
Aug 13, 5:46 AM CDTTornado WarningDMXGreene29 min
Aug 13, 5:51 AM CDTSevere Thunderstorm WarningDMXBoone, Carroll, Dallas, Greene, Guthrie, Polk39 min
Aug 13, 6:27 AM CDTSevere Thunderstorm WarningDMXBoone, Dallas, Jasper, Marshall, Polk, Story48 min
Aug 13, 6:44 AM CDTTornado WarningDMXMarshall, Story20 min
Aug 13, 6:48 AM CDTTornado Warning Tornado observedDMXJasper, Marshall, Polk, Story27 min
Aug 13, 7:11 AM CDTSevere Thunderstorm WarningDMXJasper, Marshall, Poweshiek, Story, Tama49 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2026Every 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.