Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 40, NWS Des Moines, IA

June 20, 2021Poweshiek County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Jun 20, 2021, 6:13 PM CDT for Poweshiek County, Iowa. It was in force for 62 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: Jun 20, 2021, 6:13 PM CDT (23:13 UTC)
Expired: Jun 20, 2021, 7:15 PM CDT
In force: 62 min
Issued by: NWS Des Moines, IA
Area: Storm-based polygon
Tornado: Possible
Hail: 1.0 in
Wind: 60.0 mph

County Poweshiek County, IA

The radar

The Des Moines radar (KDMX), 105 km from the middle of the area, began a volume at 23:14 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.

Issued	Product	Office	Lasted
Jun 20, 4:01 PM CDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 11.2 hours before the alert went out and 164 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: 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.

174 
WUUS53 KDMX 202313
SVRDMX
IAC157-210015-
/O.NEW.KDMX.SV.W.0040.210620T2313Z-210621T0015Z/

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

The National Weather Service in Des Moines  has issued a

* Severe Thunderstorm Warning for...
  Southern Poweshiek County in central Iowa...

* Until 715 PM CDT.

* At 612 PM CDT, a severe thunderstorm was located 7 miles northwest
  of Montezuma, moving east 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.

* This severe thunderstorm will be near...
  Montezuma around 625 PM CDT.

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

This includes Interstate 80 between mile markers 184 and 204.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4151 9240 4157 9274 4174 9270 4172 9230
      4151 9230
TIME...MOT...LOC 2312Z 274DEG 20KT 4165 9264 

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

REV

2 follow-up statements

433 
WWUS53 KDMX 202347
SVSDMX

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

IAC157-210015-
/O.CON.KDMX.SV.W.0040.000000T0000Z-210621T0015Z/
Poweshiek IA-
647 PM CDT Sun Jun 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 715 PM CDT
FOR SOUTHEASTERN POWESHIEK COUNTY...

At 647 PM CDT, a severe thunderstorm was located 7 miles southeast of
Brooklyn, or 8 miles northeast of Montezuma, moving east 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.

This severe thunderstorm will remain over mainly rural areas of
southeastern Poweshiek County, including the following locations...
Deep River, Guernsey and Malcom.

This includes Interstate 80 between mile markers 188 and 204.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4151 9240 4157 9265 4173 9262 4172 9230
      4151 9230
TIME...MOT...LOC 2347Z 274DEG 20KT 4164 9238 

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

REV

657 
WWUS53 KDMX 210018
SVSDMX

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

IAC157-210028-
/O.EXP.KDMX.SV.W.0040.000000T0000Z-210621T0015Z/
Poweshiek IA-
718 PM CDT Sun Jun 20 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN POWESHIEK COUNTY
HAS EXPIRED...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning has been allowed to expire.  However gusty
winds are still possible with this thunderstorm.

A Severe Thunderstorm Watch remains in effect until 1100 PM CDT for
central Iowa.

LAT...LON 4151 9240 4157 9265 4173 9262 4172 9230
      4151 9230
TIME...MOT...LOC 0018Z 274DEG 20KT 4163 9216 

$$

REV

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 20, 3:38 PM CDT	Special Weather Statement	DMX	Dallas	37 min
Jun 20, 4:20 PM CDT	Severe Thunderstorm Warning	DMX	Clarke, Madison, Union	55 min
Jun 20, 4:47 PM CDT	Severe Thunderstorm Warning	DMX	Jasper	43 min
Jun 20, 4:53 PM CDT	Severe Thunderstorm Warning	DMX	Clarke, Decatur, Ringgold, Union	52 min
Jun 20, 4:54 PM CDT	Severe Thunderstorm Warning	DMX	Bremer, Butler, Franklin	51 min
Jun 20, 5:33 PM CDT	Severe Thunderstorm Warning	DMX	Jasper, Poweshiek	42 min
Jun 20, 5:35 PM CDT	Severe Thunderstorm Warning	DMX	Clarke, Decatur, Lucas, Wayne	40 min
Jun 20, 5:55 PM CDT	Severe Thunderstorm Warning	DMX	Jasper, Mahaska, Marion	50 min
Jun 20, 5:59 PM CDT	Severe Thunderstorm Warning	DMX	Decatur, Wayne	46 min
Jun 20, 6:04 PM CDT	Tornado Warning	DMX	Decatur	26 min
Jun 20, 6:15 PM CDT	Severe Thunderstorm Warning	DMX	Decatur, Wayne	30 min
Jun 20, 6:20 PM CDT	Severe Thunderstorm Warning	DMX	Black Hawk	55 min
Jun 20, 6:37 PM CDT	Tornado Warning	DMX	Mahaska, Marion	23 min
Jun 20, 6:43 PM CDT	Severe Thunderstorm Warning	DMX	Decatur, Wayne	47 min
Jun 20, 6:59 PM CDT	Tornado Warning	DMX	Mahaska, Marion	31 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.