Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 94, NWS Des Moines, IA

August 24, 2021Butler County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Aug 24, 2021, 1:44 PM CDT for Butler County, Iowa. It was in force for 31 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Aug 24, 2021, 1:44 PM CDT (18:44 UTC)
Expired: Aug 24, 2021, 2:15 PM CDT
In force: 31 min
Issued by: NWS Des Moines, IA
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

County Butler County, IA

The radar

The Des Moines radar (KDMX), 154 km from the middle of the area, began a volume at 18:44 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, 6.7 hours before the alert went out and 230 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: 1192 J/kg
Mixed-layer CIN: -180 J/kg
Mixed-layer LCL: 1234 m above ground
0-6 km bulk shear: 51 kt
0-1 km storm-relative helicity: 141 m²/s²
0-3 km storm-relative helicity: 178 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 6.9

Open this sounding in Storm Lab

The text

As transmitted.

497 
WUUS53 KDMX 241844
SVRDMX
IAC023-241915-
/O.NEW.KDMX.SV.W.0094.210824T1844Z-210824T1915Z/

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

The National Weather Service in Des Moines  has issued a

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

* Until 215 PM CDT.

* At 144 PM CDT, a severe thunderstorm was located near Greene, or 11
  miles northeast of Allison, moving east at 35 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.

* This severe thunderstorm will remain over mainly rural areas of
  northeastern Butler County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4288 9281 4291 9279 4291 9255 4286 9256
TIME...MOT...LOC 1844Z 275DEG 31KT 4290 9271 

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, 1:18 PM CDT	Severe Thunderstorm Warning Considerable damage threat	DMX	Butler	57 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.