Alert archive / Iowa / Severe Thunderstorm Warnings in 2026
Severe Thunderstorm Warning 329, NWS Des Moines, IA
NWS Des Moines, IA issued this severe thunderstorm warning at Sep 6, 2026, 2:37 PM CDT for Sac County, Iowa. It was in force for 38 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
- Sep 6, 2026, 2:37 PM CDT (19:37 UTC)
- Expired
- Sep 6, 2026, 3:15 PM CDT
- In force
- 38 min
- Issued by
- NWS Des Moines, IA
- Area
- Storm-based polygon
- Hail
- 1.0 in
- Wind
- 60.0 mph
County Sac County, IA
The radar
The Des Moines radar (KDMX), 135 km from the middle of the area, began a volume at 19:38 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, 7.6 hours before the alert went out and 300 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.
- Mixed-layer CAPE
- 257 J/kg
- Mixed-layer CIN
- -330 J/kg
- Mixed-layer LCL
- 1056 m above ground
- 0-6 km bulk shear
- 23 kt
- 0-1 km storm-relative helicity
- 24 m²/s²
- 0-3 km storm-relative helicity
- 55 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
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 Sep 6, 12:49 PM CDT, 1 hour 48 minutes earlier.
Area forecast discussion, Sep 6, 12:49 PM CDT, 1 hour 48 minutes before
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</html>Hazardous weather outlook, Sep 6, 1:07 PM CDT, 1 hour 30 minutes before
Hazardous Weather Outlook National Weather Service Des Moines IA 107 PM CDT Sun Sep 6 2026 IAZ005>007-016-017-024>028-035>039-045>050-057>062-070>075- 081>086-092>097-071815- Kossuth-Winnebago-Worth-Hancock-Cerro Gordo-Humboldt-Wright- Franklin-Butler-Bremer-Webster-Hamilton-Hardin-Grundy-Black Hawk- 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- 107 PM CDT Sun Sep 6 2026 This Hazardous Weather Outlook is for portions of central Iowa. .DAY ONE...This afternoon and tonight Thunderstorms are possible through tonight, particularly in western Iowa. A strong storm with damaging wind, heavy rain, or large hail cannot be ruled out. .DAYS TWO THROUGH SEVEN...Monday through Saturday Thunderstorms are possible again Monday night to Tuesday night across a large part of the state. An isolated severe storm is possible. Heat returns Tuesday afternoon with heat indices near 100 degrees currently being forecast. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected. && NWS Des Moines will discontinue the Hazardous Weather Outlook product (HWO) on September 30th, 2026. Weather hazards and outlooks will continue to be provided through the standard forecast channels, including weather briefing packets, forecast discussions, weather story graphics, the experimental graphical hazardous weather outlook, and updated hazard messaging. All local products and visual tools are accessible directly at weather.gov/desmoines. IAZ004-015-023-033-034-044-071815- Emmet-Palo Alto-Pocahontas-Sac-Calhoun-Crawford- 107 PM CDT Sun Sep 6 2026 This Hazardous Weather Outlook is for portions of central Iowa. .DAY ONE...This afternoon and tonight A Flood Watch for Flash Flooding is in effect for the area. Please refer to the National Weather Service website at weather.gov/desmoines for further details. In addition to the heavy rain potential, a few strong storms with damaging winds are also possible. .DAYS TWO THROUGH SEVEN...Monday through Saturday Thunderstorms are possible again Monday night to Tuesday night across a large part of the state. An isolated severe storm is possible. Heat returns Tuesday afternoon with heat indices near 100 degrees currently being forecast. .SPOTTER INFORMATION STATEMENT... Spotter activation is possible and rainfall and severe weather reports are appreciated. && NWS Des Moines will discontinue the Hazardous Weather Outlook product (HWO) on September 30th, 2026. Weather hazards and outlooks will continue to be provided through the standard forecast channels, including weather briefing packets, forecast discussions, weather story graphics, the experimental graphical hazardous weather outlook, and updated hazard messaging. All local products and visual tools are accessible directly at weather.gov/desmoines.
In the hours before
Local storm report, Sep 6, 2:02 PM CDT, 35 minutes before
Preliminary Local Storm Report
National Weather Service Des Moines IA
202 PM CDT Sun Sep 6 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0155 PM Flash Flood 1 NNE Graettinger 43.24N 94.75W
09/06/2026 Palo Alto IA Emergency Mngr
Significant ponding several feet deep with
bundles of wood floating at EPS Buildings
location on the north side of town. Water is
also over the road on North Van Gordon Ave.
&&
RDThe office that day
Everything else NWS Des Moines, IA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 6, 10:45 AM CDT | Severe Thunderstorm Warning | DMX | Emmet | 24 min |
| Sep 6, 12:02 PM CDT | Flash Flood Warning | DMX | Emmet, Palo Alto | 6 hr |
| Sep 6, 12:12 PM CDT | Flood Watch | DMX | Calhoun, Crawford, Emmet, Palo Alto, Pocahontas, Sac | 10 hr |
| Sep 6, 3:45 PM CDT | Severe Thunderstorm Warning | DMX | Adams, Union | 45 min |
| Sep 6, 3:47 PM CDT | Severe Thunderstorm Warning | DMX | Calhoun, Carroll, Crawford, Sac | 43 min |
| Sep 6, 4:13 PM CDT | Severe Thunderstorm Warning | DMX | Calhoun, Carroll, Greene, Webster | 47 min |
| Sep 6, 4:19 PM CDT | Flash Flood Warning | DMX | Crawford | 3 hr |
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.