Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 97, NWS Des Moines, IA

August 24, 20216 counties in Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Aug 24, 2021, 4:03 PM CDT for 6 counties in 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, 4:03 PM CDT (21:03 UTC)
Expired
Aug 24, 2021, 5:00 PM CDT
In force
57 min
Issued by
NWS Des Moines, IA
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Black Hawk County, IA, Grundy County, IA, Hardin County, IA, Marshall County, IA, Poweshiek County, IA, Tama County, IA

The radar

The Des Moines radar (KDMX), 92 km from the middle of the area, began a volume at 21:04 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

TimeReportWhereRemark
Aug 24, 4:28 PM CDTTSTM WND DMG4 Sw Albion, IAOFFICERS REPORTED DAMAGE TO THEIR HOME INCLUDING SHINGLES OFF AND TREES DOWN. DELAYED REPORT, TIME ESTIMATED VIA RADAR.

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

The watch it was issued in

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

IssuedProductOfficeLasted
Aug 24, 1:52 PM CDTSevere Thunderstorm WatchSPC5 hr

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 9.1 hours before the alert went out and 192 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, Davenport, at 12:00Z on 2021-08-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1809 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, Davenport, at 12:00Z on 2021-08-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 35 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
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.

358 
WUUS53 KDMX 242103
SVRDMX
IAC013-075-083-127-157-171-242200-
/O.NEW.KDMX.SV.W.0097.210824T2103Z-210824T2200Z/

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

The National Weather Service in Des Moines  has issued a

* Severe Thunderstorm Warning for...
  Northeastern Poweshiek County in central Iowa...
  Marshall County in central Iowa...
  Southeastern Hardin County in central Iowa...
  Southwestern Black Hawk County in northeastern Iowa...
  Tama County in central Iowa...
  Grundy County in central Iowa...

* Until 500 PM CDT.

* At 402 PM CDT, a severe thunderstorm was located near Conrad, or 9
  miles southeast of Eldora, moving east at 50 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...
  Reinbeck, Traer and Dysart.

This includes Interstate 380 between mile markers 71 and 73.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4172 9230 4201 9323 4210 9323 4252 9305
      4253 9229
TIME...MOT...LOC 2102Z 276DEG 44KT 4226 9298 

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

$$

Krull
2 follow-up statements
476 
WWUS53 KDMX 242135
SVSDMX

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

IAC083-242144-
/O.CAN.KDMX.SV.W.0097.000000T0000Z-210824T2200Z/
Hardin IA-
435 PM CDT Tue Aug 24 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN HARDIN 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 700 PM CDT for
central and northeastern Iowa.

LAT...LON 4172 9230 4199 9315 4222 9296 4244 9282
      4253 9229
TIME...MOT...LOC 2134Z 276DEG 44KT 4222 9245 

$$

IAC013-075-127-157-171-242200-
/O.CON.KDMX.SV.W.0097.000000T0000Z-210824T2200Z/
Poweshiek IA-Marshall IA-Black Hawk IA-Tama IA-Grundy IA-
435 PM CDT Tue Aug 24 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 500 PM CDT
FOR NORTHEASTERN POWESHIEK...MARSHALL...SOUTHWESTERN BLACK HAWK...
TAMA AND CENTRAL GRUNDY COUNTIES...

At 434 PM CDT, a severe thunderstorm was located over Traer, or 17
miles northeast of Toledo, moving east at 50 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...
Waterloo, Cedar Falls, Marshalltown, Grundy Center, Toledo,
Evansdale, Tama, Hudson, Traer, Reinbeck, Dysart, Dike, Conrad,
Meskwaki Casino, Crossroads Mall, Gladbrook, Le Grand, Victor, Garwin
and Gilman.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4172 9230 4199 9315 4222 9296 4244 9282
      4253 9229
TIME...MOT...LOC 2134Z 276DEG 44KT 4222 9245 

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

$$

Hagenhoff
447 
WWUS53 KDMX 242158
SVSDMX

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

IAC013-075-127-157-171-242206-
/O.EXP.KDMX.SV.W.0097.000000T0000Z-210824T2200Z/
Poweshiek IA-Marshall IA-Black Hawk IA-Tama IA-Grundy IA-
458 PM CDT Tue Aug 24 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN POWESHIEK...
MARSHALL...SOUTHWESTERN BLACK HAWK...TAMA AND CENTRAL GRUNDY COUNTIES
WILL EXPIRE AT 500 PM CDT...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning will be allowed to expire.  However small hail
and gusty winds are still possible with this thunderstorm.

A Severe Thunderstorm Watch remains in effect until 700 PM CDT for
central and northeastern Iowa.

LAT...LON 4172 9230 4199 9315 4222 9296 4244 9282
      4253 9229
TIME...MOT...LOC 2156Z 276DEG 44KT 4219 9212 

$$

Hagenhoff

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 24, 11:06 AM CDTSpecial Weather StatementDMXEmmet24 min
Aug 24, 11:30 AM CDTSpecial Weather StatementDMXKossuth, Winnebago45 min
Aug 24, 12:07 PM CDTSpecial Weather StatementDMXCerro Gordo, Hancock, Worth68 min
Aug 24, 12:26 PM CDTSevere Thunderstorm WarningDMXCerro Gordo, Hancock49 min
Aug 24, 12:51 PM CDTSevere Thunderstorm WarningDMXCerro Gordo, Franklin, Hancock, Wright54 min
Aug 24, 1:18 PM CDTSevere Thunderstorm Warning Considerable damage threatDMXButler57 min
Aug 24, 1:44 PM CDTSevere Thunderstorm WarningDMXButler31 min
Aug 24, 1:53 PM CDTSevere Thunderstorm WarningDMXBlack Hawk, Bremer67 min
Aug 24, 2:17 PM CDTSpecial Weather StatementDMXButler28 min
Aug 24, 3:00 PM CDTSpecial Weather StatementDMXBlack Hawk, Bremer30 min
Aug 24, 3:28 PM CDTSevere Thunderstorm WarningDMXHamilton, Hardin, Marshall, Story47 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.