Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 84, NWS Des Moines, IA

August 10, 2021Clarke County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Aug 10, 2021, 12:50 PM CDT for Clarke County, Iowa. It was in force for 25 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 10, 2021, 12:50 PM CDT (17:50 UTC)
Expired
Aug 10, 2021, 1:15 PM CDT
In force
25 min
Issued by
NWS Des Moines, IA
Area
Storm-based polygon
Hail
1.0 in
Wind
50.0 mph

County Clarke County, IA

The radar

The Des Moines radar (KDMX), 77 km from the middle of the area, began a volume at 17:51 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

Omaha, NE (KOAX), launched 12:00Z, 5.8 hours before the alert went out and 209 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, Omaha, NE at 12:00Z on 2021-08-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 962 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Omaha, NE at 12:00Z on 2021-08-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -123 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
962 J/kg
Mixed-layer CIN
-346 J/kg
Mixed-layer LCL
1688 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
-123 m²/s²
0-3 km storm-relative helicity
-41 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.2

Open this sounding in Storm Lab

The text

As transmitted.

074 
WUUS53 KDMX 101750
SVRDMX
IAC039-101815-
/O.NEW.KDMX.SV.W.0084.210810T1750Z-210810T1815Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Des Moines IA
1250 PM CDT Tue Aug 10 2021

The National Weather Service in Des Moines  has issued a

* Severe Thunderstorm Warning for...
  Northwestern Clarke County in south central Iowa...

* Until 115 PM CDT.

* At 1249 PM CDT, a severe thunderstorm was located 8 miles west of
  Lakeside Casino, or 9 miles west of Osceola, moving northeast at 
  30 mph. Trained spotters reported dime to quarter sized hail 
  with this storm in Murray.

  HAZARD...Quarter size hail.

  SOURCE...Trained weather spotters.

  IMPACT...Damage to vehicles is expected.

* This severe thunderstorm will be near...
  Lakeside Casino around 105 PM CDT.

Other locations in the path of this severe thunderstorm include
Osceola.

This includes Interstate 35 between mile markers 31 and 43.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4100 9402 4106 9401 4116 9382 4116 9377
      4101 9367 4095 9398
TIME...MOT...LOC 1749Z 243DEG 24KT 4104 9395 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...<50 MPH

$$

Hagenhoff
2 follow-up statements
712 
WWUS53 KDMX 101805
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
105 PM CDT Tue Aug 10 2021

IAC039-101815-
/O.CON.KDMX.SV.W.0084.000000T0000Z-210810T1815Z/
Clarke IA-
105 PM CDT Tue Aug 10 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 115 PM CDT
FOR CENTRAL CLARKE COUNTY...

At 102 PM CDT, a severe thunderstorm was located near Lakeside
Casino, or near Osceola, moving northeast at 30 mph.

HAZARD...Quarter size hail.

SOURCE...Trained weather spotters.

IMPACT...Damage to vehicles is expected.

This severe storm will be near...
  Lakeside Casino around 105 PM CDT.
  Osceola around 110 PM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4099 9385 4107 9392 4116 9377 4101 9367
TIME...MOT...LOC 1802Z 243DEG 24KT 4108 9385 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...<50 MPH

$$

Hagenhoff
505 
WWUS53 KDMX 101814
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
114 PM CDT Tue Aug 10 2021

IAC039-101824-
/O.EXP.KDMX.SV.W.0084.000000T0000Z-210810T1815Z/
Clarke IA-
114 PM CDT Tue Aug 10 2021

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL CLARKE COUNTY WILL
EXPIRE AT 115 PM CDT...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning will be allowed to expire.

LAT...LON 4099 9385 4107 9392 4116 9377 4101 9367
TIME...MOT...LOC 1814Z 243DEG 24KT 4111 9377 

$$

Hagenhoff

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 10, 12:56 PM CDTHeat AdvisoryDMXAdair, Adams, Appanoose, Audubon, Cass, Clarke and 18 more30 hr
Aug 10, 1:48 PM CDTSevere Thunderstorm WarningDMXBlack Hawk, Bremer, Butler42 min
Aug 10, 2:14 PM CDTSevere Thunderstorm WarningDMXBlack Hawk, Bremer46 min
Aug 10, 2:57 PM CDTSevere Thunderstorm WarningDMXBlack Hawk18 min
Aug 10, 3:00 PM CDTSevere Thunderstorm WarningDMXJasper, Marshall, Poweshiek, Tama60 min
Aug 10, 3:59 PM CDTSpecial Weather StatementDMXTama46 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2021Every 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.