Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 42, NWS Des Moines, IA

June 20, 2021Black Hawk County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Jun 20, 2021, 6:20 PM CDT for Black Hawk County, Iowa. It was in force for 55 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, 6:20 PM CDT (23:20 UTC)
Expired: Jun 20, 2021, 7:15 PM CDT
In force: 55 min
Issued by: NWS Des Moines, IA
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

County Black Hawk County, IA

The radar

The Des Moines radar (KDMX), 140 km from the middle of the area, began a volume at 23:19 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, 1:42 PM CDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 11.3 hours before the alert went out and 177 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.

636 
WUUS53 KDMX 202320
SVRDMX
IAC013-210015-
/O.NEW.KDMX.SV.W.0042.210620T2320Z-210621T0015Z/

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

The National Weather Service in Des Moines  has issued a

* Severe Thunderstorm Warning for...
  Central Black Hawk County in northeastern Iowa...

* Until 715 PM CDT.

* At 619 PM CDT, a severe thunderstorm was located over Hudson, or
  near Cedar Falls, 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...
  Waterloo Municipal Airport around 625 PM CDT.
  Crossroads Mall around 635 PM CDT.

Other locations in the path of this severe thunderstorm include
Waterloo, Evansdale, Elk Run Heights and Jesup.

This includes Interstate 380 between mile markers 56 and 73.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4238 9253 4247 9253 4247 9255 4255 9254
      4256 9208 4247 9208 4247 9206 4232 9206
TIME...MOT...LOC 2319Z 274DEG 20KT 4246 9245 

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

REV

1 follow-up statement

325 
WWUS53 KDMX 202340
SVSDMX

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

IAC013-210015-
/O.CON.KDMX.SV.W.0042.000000T0000Z-210621T0015Z/
Black Hawk IA-
640 PM CDT Sun Jun 20 2021

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

At 640 PM CDT, a severe thunderstorm was located over Evansdale, or
near Waterloo, 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.

Locations impacted include...
  Elk Run Heights and Jesup.

This includes Interstate 380 between mile markers 56 and 73.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4235 9231 4246 9236 4248 9234 4255 9232
      4256 9208 4247 9208 4247 9206 4232 9206
TIME...MOT...LOC 2340Z 274DEG 20KT 4245 9229 

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

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, 6:13 PM CDT	Severe Thunderstorm Warning	DMX	Poweshiek	62 min
Jun 20, 6:15 PM CDT	Severe Thunderstorm Warning	DMX	Decatur, Wayne	30 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.