Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 66, NWS Des Moines, IA

July 9, 2021Audubon County, Cass County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Jul 9, 2021, 11:41 PM CDT for Audubon County, Cass County, Iowa. It was in force for 49 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
Jul 9, 2021, 11:41 PM CDT (04:41 UTC)
Expired
Jul 10, 2021, 12:30 AM CDT
In force
49 min
Issued by
NWS Des Moines, IA
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Audubon County, IA, Cass County, IA

The radar

The Omaha radar (KOAX), 107 km from the middle of the area, began a volume at 04:44 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Jul 9, 9:58 PM CDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 4.7 hours before the alert went out and 107 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 00:00Z on 2021-07-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2603 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 00:00Z on 2021-07-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 90 square meters per square second.19395878Sfc1 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
2603 J/kg
Mixed-layer CIN
-130 J/kg
Mixed-layer LCL
1447 m above ground
0-6 km bulk shear
45 kt
0-1 km storm-relative helicity
90 m²/s²
0-3 km storm-relative helicity
186 m²/s²
Significant tornado parameter
0.6
Supercell composite
8.1

Open this sounding in Storm Lab

The text

As transmitted.

649 
WUUS53 KDMX 100441
SVRDMX
IAC009-029-100530-
/O.NEW.KDMX.SV.W.0066.210710T0441Z-210710T0530Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Des Moines IA
1141 PM CDT Fri Jul 9 2021

The National Weather Service in Des Moines  has issued a

* Severe Thunderstorm Warning for...
  Northwestern Cass County in southwestern Iowa...
  Southwestern Audubon County in west central Iowa...

* Until 1230 AM CDT.

* At 1141 PM CDT, a severe thunderstorm was located near Walnut, or
  10 miles northwest of Atlantic, moving south at 25 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...
  Atlantic.

This includes Interstate 80 between mile markers 50 and 59.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4131 9515 4150 9515 4151 9504 4160 9504
      4134 9485 4126 9516 4130 9516
TIME...MOT...LOC 0441Z 337DEG 21KT 4152 9513 

HAIL...1.00IN
WIND...60MPH
 
$$

Ansorge
1 follow-up statement
273 
WWUS53 KDMX 100501
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
1201 AM CDT Sat Jul 10 2021

IAC009-100511-
/O.CAN.KDMX.SV.W.0066.000000T0000Z-210710T0530Z/
Audubon IA-
1201 AM CDT Sat Jul 10 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN AUDUBON COUNTY IS
CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

A Severe Thunderstorm Watch remains in effect until 500 AM CDT for
southwestern Iowa.

LAT...LON 4131 9515 4150 9515 4150 9497 4134 9485
      4126 9516 4130 9516
TIME...MOT...LOC 0501Z 336DEG 27KT 4134 9503 

$$

IAC029-100530-
/O.CON.KDMX.SV.W.0066.000000T0000Z-210710T0530Z/
Cass IA-
1201 AM CDT Sat Jul 10 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1230 AM CDT
FOR NORTHWESTERN CASS COUNTY...

At 1201 AM CDT, a severe thunderstorm was located near Atlantic,
moving southeast at 30 mph.

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

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, and trees.

Locations impacted include...
Atlantic, Lewis, Marne, Cold Springs State Park and Atlantic
Municipal Airport.

This includes Interstate 80 between mile markers 50 and 59.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4131 9515 4150 9515 4150 9497 4134 9485
      4126 9516 4130 9516
TIME...MOT...LOC 0501Z 336DEG 27KT 4134 9503 

HAIL...0.75IN
WIND...60MPH
 
$$

Ansorge

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 9, 9:16 PM CDTSevere Thunderstorm WarningDMXRinggold44 min
Jul 9, 9:31 PM CDTSevere Thunderstorm WarningDMXClarke, Decatur, Ringgold, Union15 min
Jul 9, 9:38 PM CDTSevere Thunderstorm WarningDMXRinggold52 min
Jul 9, 10:21 PM CDTSevere Thunderstorm WarningDMXRinggold39 min
Jul 9, 11:56 PM CDTSevere Thunderstorm WarningDMXAdair, Adams, Cass49 min
Jul 10, 12:41 AM CDTSevere Thunderstorm WarningDMXAdair, Adams, Cass, Ringgold, Taylor, Union64 min
Jul 10, 2:49 PM CDTSpecial Weather StatementDMXCarroll, Crawford, Sac56 min
Jul 10, 4:36 PM CDTTornado WarningDMXDallas, Guthrie24 min
Jul 10, 5:00 PM CDTTornado WarningDMXDallas30 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.