Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 11, NWS Des Moines, IA

June 18, 20214 counties in Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Jun 18, 2021, 10:06 PM CDT for 4 counties in Iowa. It was in force for 39 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 18, 2021, 10:06 PM CDT (03:06 UTC)
Expired: Jun 18, 2021, 10:45 PM CDT
In force: 39 min
Issued by: NWS Des Moines, IA
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

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

The radar

The Des Moines radar (KDMX), 72 km from the middle of the area, began a volume at 03:10 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 18, 10:39 PM CDT	HAIL 3	Lorimor, IA	VIA PICTURES ON SOCIAL MEDIA. TIME ESTIMATED FROM RADAR.

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

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 3.1 hours before the alert went out and 178 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: 2090 J/kg
Mixed-layer CIN: -169 J/kg
Mixed-layer LCL: 1569 m above ground
0-6 km bulk shear: 59 kt
0-1 km storm-relative helicity: 46 m²/s²
0-3 km storm-relative helicity: 307 m²/s²
Significant tornado parameter: -0.0
Supercell composite: -0.3

Open this sounding in Storm Lab

The text

As transmitted.

346 
WUUS53 KDMX 190306
SVRDMX
IAC001-039-121-175-190345-
/O.NEW.KDMX.SV.W.0011.210619T0306Z-210619T0345Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Des Moines IA
1006 PM CDT Fri Jun 18 2021

The National Weather Service in Des Moines  has issued a

* Severe Thunderstorm Warning for...
  Southwestern Madison County in south central Iowa...
  Northeastern Union County in south central Iowa...
  Northwestern Clarke County in south central Iowa...
  Southeastern Adair County in southwestern Iowa...

* Until 1045 PM CDT.

* At 1005 PM CDT, a severe thunderstorm was located 8 miles north of
  Green Valley Lake, or 8 miles southeast of Greenfield, moving east
  at 35 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
  southwestern Madison, northeastern Union, northwestern Clarke and
  southeastern Adair Counties, including the following locations...
  Orient, Lorimor, Macksburg and East Peru.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4116 9444 4128 9444 4134 9394 4111 9394
TIME...MOT...LOC 0305Z 271DEG 29KT 4122 9435 

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

Martin

2 follow-up statements

593 
WWUS53 KDMX 190312
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
1012 PM CDT Fri Jun 18 2021

IAC001-039-121-175-190345-
/O.CON.KDMX.SV.W.0011.000000T0000Z-210619T0345Z/
Madison IA-Union IA-Clarke IA-Adair IA-
1012 PM CDT Fri Jun 18 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1045 PM CDT
FOR SOUTHWESTERN MADISON...NORTHEASTERN UNION...NORTHWESTERN CLARKE
AND SOUTHEASTERN ADAIR COUNTIES...

At 1012 PM CDT, a severe thunderstorm was located 9 miles northeast
of Green Valley Lake, or 11 miles southeast of Greenfield, moving
east at 35 mph.

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

SOURCE...Trained weather spotters.

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...
Winterset, Lorimor, East Peru and Macksburg. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4116 9438 4129 9436 4134 9394 4111 9394
TIME...MOT...LOC 0312Z 271DEG 29KT 4122 9427 

HAIL...1.75IN
WIND...60MPH
 
$$

Martin

564 
WWUS53 KDMX 190334
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
1034 PM CDT Fri Jun 18 2021

IAC001-190343-
/O.CAN.KDMX.SV.W.0011.000000T0000Z-210619T0345Z/
Adair IA-
1034 PM CDT Fri Jun 18 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN ADAIR 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 500 AM CDT for
south central Iowa.

LAT...LON 4114 9421 4131 9418 4134 9394 4111 9394
TIME...MOT...LOC 0333Z 271DEG 29KT 4122 9404 

$$

IAC039-121-175-190345-
/O.CON.KDMX.SV.W.0011.000000T0000Z-210619T0345Z/
Madison IA-Union IA-Clarke IA-
1034 PM CDT Fri Jun 18 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1045 PM CDT
FOR SOUTHWESTERN MADISON...NORTHEASTERN UNION AND NORTHWESTERN CLARKE
COUNTIES...

At 1033 PM CDT, a severe thunderstorm was located 8 miles south of
Winterset, moving east at 35 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...
Winterset, Lorimor, East Peru and Macksburg. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4114 9421 4131 9418 4134 9394 4111 9394
TIME...MOT...LOC 0333Z 271DEG 29KT 4122 9404 

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

Martin

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 18, 9:56 PM CDT	Severe Thunderstorm Warning	DMX	Clarke, Lucas, Madison, Marion, Warren	49 min
Jun 18, 10:39 PM CDT	Severe Thunderstorm Warning	DMX	Lucas, Monroe, Wayne	51 min
Jun 18, 10:43 PM CDT	Severe Thunderstorm Warning	DMX	Clarke, Lucas, Madison, Union, Warren	47 min
Jun 18, 10:45 PM CDT	Severe Thunderstorm Warning	DMX	Mahaska, Marion, Monroe, Wapello	45 min
Jun 18, 10:54 PM CDT	Severe Thunderstorm Warning	DMX	Adair, Cass	51 min
Jun 18, 11:05 PM CDT	Severe Thunderstorm Warning	DMX	Mahaska, Marion	25 min
Jun 18, 11:10 PM CDT	Severe Thunderstorm Warning	DMX	Appanoose, Lucas, Monroe, Wayne	50 min
Jun 18, 11:14 PM CDT	Severe Thunderstorm Warning	DMX	Adair, Madison	46 min
Jun 18, 11:19 PM CDT	Severe Thunderstorm Warning	DMX	Mahaska	26 min
Jun 18, 11:22 PM CDT	Severe Thunderstorm Warning	DMX	Appanoose, Davis, Monroe, Wapello	53 min
Jun 18, 11:25 PM CDT	Severe Thunderstorm Warning	DMX	Clarke, Decatur, Lucas, Wayne	50 min
Jun 18, 11:32 PM CDT	Severe Thunderstorm Warning	DMX	Cass	28 min
Jun 18, 11:37 PM CDT	Severe Thunderstorm Warning	DMX	Adair, Adams, Union	53 min
Jun 18, 11:54 PM CDT	Severe Thunderstorm Warning	DMX	Clarke, Madison, Warren	36 min
Jun 18, 11:55 PM CDT	Severe Thunderstorm Warning	DMX	Appanoose, Lucas, Monroe, Wayne	50 min
Jun 18, 11:59 PM CDT	Severe Thunderstorm Warning	DMX	Adair, Adams, Clarke, Madison, Ringgold, Union	46 min
Jun 19, 12:13 AM CDT	Severe Thunderstorm Warning	DMX	Adams	26 min
Jun 19, 12:14 AM CDT	Severe Thunderstorm Warning	DMX	Davis, Wapello	31 min
Jun 19, 12:25 AM CDT	Severe Thunderstorm Warning	DMX	Clarke, Lucas, Marion, Warren	35 min
Jun 19, 12:29 AM CDT	Severe Thunderstorm Warning	DMX	Appanoose, Davis	46 min
Jun 19, 12:44 AM CDT	Severe Thunderstorm Warning	DMX	Lucas, Marion, Monroe	31 min
Jun 19, 3:59 AM CDT	Special Weather Statement	DMX	Davis	46 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.