Alert archive / Iowa / Severe Thunderstorm Warnings in 2025

Severe Thunderstorm Warning 252, NWS Des Moines, IA

September 22, 20255 counties in Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Sep 22, 2025, 9:02 PM CDT for 5 counties in Iowa. It was in force for 43 min. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Sep 22, 2025, 9:02 PM CDT (02:02 UTC)
Expired: Sep 22, 2025, 9:45 PM CDT
In force: 43 min
Issued by: NWS Des Moines, IA
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Boone County, IA, Hamilton County, IA, Hardin County, IA, Marshall County, IA, Story County, IA

The radar

The Des Moines radar (KDMX), 38 km from the middle of the area, began a volume at 02:01 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.

What was reported inside it

Time	Report	Where	Remark
Sep 22, 9:20 PM CDT	TSTM WND DMG	Ames, IA	Several large tree branches greater than 3 inches in diameter down around the city.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 2.0 hours before the alert went out and 251 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: 2545 J/kg
Mixed-layer CIN: -9 J/kg
Mixed-layer LCL: 1653 m above ground
0-6 km bulk shear: 35 kt
0-1 km storm-relative helicity: 71 m²/s²
0-3 km storm-relative helicity: 127 m²/s²
Significant tornado parameter: 0.4
Supercell composite: 6.5

Open this sounding in Storm Lab

The text

As transmitted.

734 
WUUS53 KDMX 230202
SVRDMX
IAC015-079-083-127-169-230245-
/O.NEW.KDMX.SV.W.0252.250923T0202Z-250923T0245Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Des Moines IA
902 PM CDT Mon Sep 22 2025

The National Weather Service in Des Moines has issued a

* Severe Thunderstorm Warning for...
  Story County in central Iowa...
  Southwestern Hardin County in central Iowa...
  Southwestern Marshall County in central Iowa...
  Southern Hamilton County in central Iowa...
  Eastern Boone County in central Iowa...

* Until 945 PM CDT.

* At 901 PM CDT, a severe thunderstorm was located over Story City,
  or 11 miles north of Ames, moving south at 30 mph.

  HAZARD...60 mph wind gusts and quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Hail damage to vehicles is expected. Expect wind damage 
           to roofs, siding, and trees.

* Locations impacted include...
  Ames, Nevada, Story City, Huxley, Slater, Roland, Jewell Junction,
  Gilbert, Iowa State Center, Maxwell, Colo, Cambridge, Zearing,
  Radcliffe, Ellsworth, Collins, Stanhope, McCallsburg, Sheldahl, and
  Kelley.

This includes Interstate 35 between mile markers 102 and 138.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4186 9343 4186 9376 4237 9386 4240 9338
      4187 9317
TIME...MOT...LOC 0201Z 344DEG 27KT 4218 9358 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Hagenhoff

1 follow-up statement

727 
WWUS53 KDMX 230227
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
927 PM CDT Mon Sep 22 2025

IAC079-083-230236-
/O.CAN.KDMX.SV.W.0252.000000T0000Z-250923T0245Z/
Hardin IA-Hamilton IA-
927 PM CDT Mon Sep 22 2025

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN HARDIN AND
SOUTHERN HAMILTON COUNTIES IS CANCELLED...

The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

LAT...LON 4186 9339 4186 9376 4221 9383 4221 9331
      4187 9317
TIME...MOT...LOC 0226Z 344DEG 27KT 4200 9351 

$$

IAC015-127-169-230245-
/O.CON.KDMX.SV.W.0252.000000T0000Z-250923T0245Z/
Story IA-Marshall IA-Boone IA-
927 PM CDT Mon Sep 22 2025

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 945 PM CDT
FOR STORY...SOUTHWESTERN MARSHALL AND EASTERN BOONE COUNTIES...

At 926 PM CDT, a severe thunderstorm was located over Nevada, moving
south at 30 mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect wind damage to 
         roofs, siding, and trees.

Locations impacted include...
Ames, Nevada, Story City, Huxley, Slater, Roland, Gilbert, Iowa State
Center, Maxwell, Colo, Cambridge, Zearing, Collins, McCallsburg,
Sheldahl, Kelley, Rhodes, and Ames Municipal Airport.

This includes Interstate 35 between mile markers 103 and 126.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4186 9339 4186 9376 4221 9383 4221 9331
      4187 9317
TIME...MOT...LOC 0226Z 344DEG 27KT 4200 9351 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Hagenhoff

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 22, 7:40 PM CDT	Severe Thunderstorm Warning	DMX	Black Hawk	29 min
Sep 22, 7:55 PM CDT	Severe Thunderstorm Warning	DMX	Humboldt, Webster, Wright	50 min
Sep 22, 7:59 PM CDT	Severe Thunderstorm Warning	DMX	Wright	46 min
Sep 22, 8:22 PM CDT	Severe Thunderstorm Warning	DMX	Hamilton, Webster, Wright	38 min
Sep 22, 8:35 PM CDT	Severe Thunderstorm Warning	DMX	Calhoun, Webster	40 min
Sep 22, 9:05 PM CDT	Severe Thunderstorm Warning	DMX	Boone, Hamilton, Story, Webster	40 min
Sep 22, 10:23 PM CDT	Severe Thunderstorm Warning	DMX	Boone, Greene	52 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2025 Every 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.