Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 32, NWS Des Moines, IA

June 20, 2021Clarke County, Madison County, Union County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Jun 20, 2021, 4:20 PM CDT for Clarke County, Madison County, Union County, Iowa. It was in force for 55 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, 4:20 PM CDT (21:20 UTC)
Expired: Jun 20, 2021, 5:15 PM CDT
In force: 55 min
Issued by: NWS Des Moines, IA
Area: Storm-based polygon
Tornado: Possible
Hail: 1.25 in
Wind: 60.0 mph

Counties Clarke County, IA, Madison County, IA, Union County, IA

The radar

The Des Moines radar (KDMX), 80 km from the middle of the area, began a volume at 21:21 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

Time	Report	Where	Remark
Jun 20, 4:34 PM CDT	HAIL 2	5 Nne Afton, IA

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.

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

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 9.3 hours before the alert went out and 190 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: 9 J/kg
Mixed-layer CIN: -220 J/kg
Mixed-layer LCL: 932 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 60 m²/s²
0-3 km storm-relative helicity: 278 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

193 
WUUS53 KDMX 202120
SVRDMX
IAC039-121-175-202215-
/O.NEW.KDMX.SV.W.0032.210620T2120Z-210620T2215Z/

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

The National Weather Service in Des Moines  has issued a

* Severe Thunderstorm Warning for...
  Southern Madison County in south central Iowa...
  Northeastern Union County in south central Iowa...
  Western Clarke County in south central Iowa...

* Until 515 PM CDT.

* At 420 PM CDT, a severe thunderstorm was located 11 miles east of
  Creston, moving east at 30 mph.

  HAZARD...60 mph wind gusts and half dollar size hail.

  SOURCE...Radar indicated.

  IMPACT...Hail damage to vehicles is expected. Expect wind damage 
           to roofs, siding, and trees.

* Locations impacted include...
  Lakeside Casino and Osceola.

This includes Interstate 35 between mile markers 27 and 34.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4106 9435 4115 9435 4120 9379 4093 9379
TIME...MOT...LOC 2120Z 270DEG 26KT 4109 9416 

TORNADO...POSSIBLE
HAIL...1.25IN
WIND...60MPH
 
$$

Small

3 follow-up statements

447 
WWUS53 KDMX 202127
SVSDMX

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

IAC039-121-175-202215-
/O.CON.KDMX.SV.W.0032.000000T0000Z-210620T2215Z/
Madison IA-Union IA-Clarke IA-
427 PM CDT Sun Jun 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 515 PM CDT
FOR SOUTHEASTERN MADISON...NORTHEASTERN UNION AND WESTERN CLARKE
COUNTIES...

At 427 PM CDT, a severe thunderstorm was located 14 miles east of
Creston, moving east at 30 mph.

HAZARD...Tennis ball size hail and 60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...People and animals outdoors will be injured. Expect hail 
         damage to roofs, siding, windows, and vehicles. Expect wind 
         damage to roofs, siding, and trees.

Locations impacted include...
Osceola, Lakeside Casino, Murray, Lorimor, Thayer and Murray Roadside
Rest Area.

This includes Interstate 35 between mile markers 28 and 34.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

This storm is producing large hail. SEEK SHELTER NOW inside a sturdy
structure and stay away from windows.

&&

LAT...LON 4106 9428 4115 9428 4120 9379 4093 9379
TIME...MOT...LOC 2127Z 270DEG 26KT 4109 9409 

TORNADO...POSSIBLE
HAIL...2.50IN
WIND...60MPH
 
$$

Small

539 
WWUS53 KDMX 202200
SVSDMX

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

IAC039-121-175-202215-
/O.CON.KDMX.SV.W.0032.000000T0000Z-210620T2215Z/
Madison IA-Union IA-Clarke IA-
500 PM CDT Sun Jun 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 515 PM CDT
FOR SOUTHEASTERN MADISON...EAST CENTRAL UNION AND WESTERN CLARKE
COUNTIES...

At 500 PM CDT, a severe thunderstorm was located near Lakeside
Casino, or near Osceola, moving east at 30 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...
Osceola, Lakeside Casino, Murray, Thayer and Murray Roadside Rest
Area.

This includes Interstate 35 between mile markers 27 and 34.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4104 9420 4108 9412 4118 9379 4093 9379
TIME...MOT...LOC 2200Z 270DEG 26KT 4109 9377 

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

Small

793 
WWUS53 KDMX 202218
SVSDMX

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

IAC039-121-175-202227-
/O.EXP.KDMX.SV.W.0032.000000T0000Z-210620T2215Z/
Madison IA-Union IA-Clarke IA-
518 PM CDT Sun Jun 20 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN MADISON...EAST
CENTRAL UNION AND WESTERN CLARKE COUNTIES 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
south central Iowa.

Remember, a Severe Thunderstorm Warning still remains in effect for 
northwester Decatur, southeast Union, northeastern Ringgold and 
southwest Clarke until 545 pm.


LAT...LON 4104 9420 4108 9412 4118 9379 4093 9379
TIME...MOT...LOC 2217Z 270DEG 26KT 4109 9361 

$$

Small

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, 4:47 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, 6:20 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.