Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 93, NWS Des Moines, IA

August 24, 2021Butler County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Aug 24, 2021, 1:18 PM CDT for Butler County, Iowa. It was in force for 57 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: Aug 24, 2021, 1:18 PM CDT (18:18 UTC)
Expired: Aug 24, 2021, 2:15 PM CDT
In force: 57 min
Issued by: NWS Des Moines, IA
Area: Storm-based polygon
Damage threat: Considerable
Hail: 1.75 in
Wind: 60.0 mph

County Butler County, IA

The radar

The Des Moines radar (KDMX), 129 km from the middle of the area, began a volume at 18:18 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
Aug 24, 1:42 PM CDT	TSTM WND GST 60	Dumont, IA	ESTIMATED 50-60 MPH. PEA-SIZED HAIL.

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

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 6.3 hours before the alert went out and 226 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: 1809 J/kg
Mixed-layer CIN: -127 J/kg
Mixed-layer LCL: 1284 m above ground
0-6 km bulk shear: 15 kt
0-1 km storm-relative helicity: 35 m²/s²
0-3 km storm-relative helicity: 9 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

888 
WUUS53 KDMX 241818
SVRDMX
IAC023-241915-
/O.NEW.KDMX.SV.W.0093.210824T1818Z-210824T1915Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Des Moines IA
118 PM CDT Tue Aug 24 2021

The National Weather Service in Des Moines  has issued a

* Severe Thunderstorm Warning for...
  Butler County in north central Iowa...

* Until 215 PM CDT.

* At 117 PM CDT, a severe thunderstorm was located near Hampton,
  moving east at 40 mph.

  HAZARD...Golf ball size hail and 60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...People and animals outdoors will be injured. Expect hail 
           damage to roofs, siding, windows, and vehicles. Expect 
           wind damage to roofs, siding, and trees.

* Locations impacted include...
  Allison, Clarksville and Shell Rock.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4256 9303 4290 9302 4287 9255 4256 9255
TIME...MOT...LOC 1817Z 284DEG 35KT 4279 9318 

THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Krull

2 follow-up statements

028 
WWUS53 KDMX 241824
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
124 PM CDT Tue Aug 24 2021

IAC023-241915-
/O.CON.KDMX.SV.W.0093.000000T0000Z-210824T1915Z/
Butler IA-
124 PM CDT Tue Aug 24 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 215 PM CDT
FOR BUTLER COUNTY...

At 124 PM CDT, a severe thunderstorm was located near Hampton, moving
east at 40 mph.

HAZARD...Golf ball size hail and 60 mph wind gusts.

SOURCE...Hampton AWOS reported a 64 MPH wind gust.

IMPACT...People and animals outdoors will be injured. Expect hail 
         damage to roofs, siding, windows, and vehicles. Expect wind 
         damage to roofs, siding, and trees.

Locations impacted include...
Allison, Parkersburg, Clarksville, Shell Rock, Aplington, Dumont, New
Hartford, Bristow, Aredale and Allison Municipal Airport.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4256 9303 4290 9302 4287 9255 4256 9255
TIME...MOT...LOC 1824Z 286DEG 33KT 4276 9314 

THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.75 IN
WIND THREAT...OBSERVED
MAX WIND GUST...60 MPH

$$

Krull

332 
WWUS53 KDMX 241841
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
141 PM CDT Tue Aug 24 2021

IAC023-241915-
/O.CON.KDMX.SV.W.0093.000000T0000Z-210824T1915Z/
Butler IA-
141 PM CDT Tue Aug 24 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 215 PM CDT
FOR BUTLER COUNTY...

At 140 PM CDT, a severe thunderstorm was located near Allison, moving
east at 45 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...
Allison, Clarksville, Shell Rock, Dumont, New Hartford, Bristow,
Aredale and Allison Municipal Airport.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4290 9302 4287 9255 4256 9255 4262 9303
TIME...MOT...LOC 1840Z 281DEG 37KT 4273 9287 

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

$$

Krull

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 24, 11:06 AM CDT	Special Weather Statement	DMX	Emmet	24 min
Aug 24, 11:30 AM CDT	Special Weather Statement	DMX	Kossuth, Winnebago	45 min
Aug 24, 12:07 PM CDT	Special Weather Statement	DMX	Cerro Gordo, Hancock, Worth	68 min
Aug 24, 12:26 PM CDT	Severe Thunderstorm Warning	DMX	Cerro Gordo, Hancock	49 min
Aug 24, 12:51 PM CDT	Severe Thunderstorm Warning	DMX	Cerro Gordo, Franklin, Hancock, Wright	54 min
Aug 24, 1:44 PM CDT	Severe Thunderstorm Warning	DMX	Butler	31 min
Aug 24, 1:53 PM CDT	Severe Thunderstorm Warning	DMX	Black Hawk, Bremer	67 min
Aug 24, 2:17 PM CDT	Special Weather Statement	DMX	Butler	28 min
Aug 24, 3:00 PM CDT	Special Weather Statement	DMX	Black Hawk, Bremer	30 min
Aug 24, 3:28 PM CDT	Severe Thunderstorm Warning	DMX	Hamilton, Hardin, Marshall, Story	47 min
Aug 24, 4:03 PM CDT	Severe Thunderstorm Warning	DMX	Black Hawk, Grundy, Hardin, Marshall, Poweshiek, Tama	57 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2021 Every severe thunderstorm warning in 2021

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.