Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 38, NWS Des Moines, IA

June 20, 2021Jasper County, Mahaska County, Marion County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Jun 20, 2021, 5:55 PM CDT for Jasper County, Mahaska County, Marion County, Iowa. It was in force for 50 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
Jun 20, 2021, 5:55 PM CDT (22:55 UTC)
Expired
Jun 20, 2021, 6:45 PM CDT
In force
50 min
Issued by
NWS Des Moines, IA
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Jasper County, IA, Mahaska County, IA, Marion County, IA

The radar

The Des Moines radar (KDMX), 61 km from the middle of the area, began a volume at 22:54 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
Jun 20, 6:43 PM CDTTORNADO2 Nnw Pella, IAPICTURE ON SOCIAL MEDIA.

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
Jun 20, 4:01 PM CDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 10.9 hours before the alert went out and 216 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 2021-06-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2021-06-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 102 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2060 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
102 m²/s²
0-3 km storm-relative helicity
84 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

336 
WUUS53 KDMX 202255
SVRDMX
IAC099-123-125-202345-
/O.NEW.KDMX.SV.W.0038.210620T2255Z-210620T2345Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Des Moines IA
555 PM CDT Sun Jun 20 2021

The National Weather Service in Des Moines  has issued a

* Severe Thunderstorm Warning for...
  Northern Marion County in south central Iowa...
  Northwestern Mahaska County in south central Iowa...
  Southern Jasper County in central Iowa...

* Until 645 PM CDT.

* At 552 PM CDT, a severe thunderstorm was located near Prairie City,
  or 13 miles east of Pleasant Hill, moving east at 20 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 be near...
  Monroe around 610 PM CDT.

Other locations in the path of this severe thunderstorm include Lake
Red Rock and Pella.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4129 9289 4144 9333 4155 9333 4163 9328
      4154 9277
TIME...MOT...LOC 2252Z 289DEG 18KT 4153 9323 

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

REV
1 follow-up statement
484 
WWUS53 KDMX 202323
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
623 PM CDT Sun Jun 20 2021

IAC099-123-125-202345-
/O.CON.KDMX.SV.W.0038.000000T0000Z-210620T2345Z/
Marion IA-Mahaska IA-Jasper IA-
623 PM CDT Sun Jun 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 645 PM CDT
FOR NORTHERN MARION...NORTHWESTERN MAHASKA AND SOUTHEASTERN JASPER
COUNTIES...

At 623 PM CDT, a severe thunderstorm was located near Monroe, or 7
miles northwest of Pella, moving east at 20 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...
  Pella.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4129 9289 4143 9330 4153 9323 4160 9311
      4154 9277
TIME...MOT...LOC 2323Z 289DEG 18KT 4148 9303 

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

REV

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 20, 3:38 PM CDTSpecial Weather StatementDMXDallas37 min
Jun 20, 4:20 PM CDTSevere Thunderstorm WarningDMXClarke, Madison, Union55 min
Jun 20, 4:47 PM CDTSevere Thunderstorm WarningDMXJasper43 min
Jun 20, 4:53 PM CDTSevere Thunderstorm WarningDMXClarke, Decatur, Ringgold, Union52 min
Jun 20, 4:54 PM CDTSevere Thunderstorm WarningDMXBremer, Butler, Franklin51 min
Jun 20, 5:33 PM CDTSevere Thunderstorm WarningDMXJasper, Poweshiek42 min
Jun 20, 5:35 PM CDTSevere Thunderstorm WarningDMXClarke, Decatur, Lucas, Wayne40 min
Jun 20, 5:59 PM CDTSevere Thunderstorm WarningDMXDecatur, Wayne46 min
Jun 20, 6:04 PM CDTTornado WarningDMXDecatur26 min
Jun 20, 6:13 PM CDTSevere Thunderstorm WarningDMXPoweshiek62 min
Jun 20, 6:15 PM CDTSevere Thunderstorm WarningDMXDecatur, Wayne30 min
Jun 20, 6:20 PM CDTSevere Thunderstorm WarningDMXBlack Hawk55 min
Jun 20, 6:37 PM CDTTornado WarningDMXMahaska, Marion23 min
Jun 20, 6:43 PM CDTSevere Thunderstorm WarningDMXDecatur, Wayne47 min
Jun 20, 6:59 PM CDTTornado WarningDMXMahaska, Marion31 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.