Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 81, NWS Des Moines, IA

July 30, 2021Clarke County, Madison County, Union County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Jul 30, 2021, 9:38 PM CDT for Clarke County, Madison County, Union County, Iowa. It was in force for 37 min. 2 reports 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: Jul 30, 2021, 9:38 PM CDT (02:38 UTC)
Expired: Jul 30, 2021, 10:15 PM CDT
In force: 37 min
Issued by: NWS Des Moines, IA
Area: Storm-based polygon
Hail: 1.0 in
Wind: 50.0 mph

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

The radar

The Des Moines radar (KDMX), 73 km from the middle of the area, began a volume at 02:36 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
Jul 30, 9:48 PM CDT	TSTM WND DMG	3 E Lorimor, IA	CORRECTS PREVIOUS TSTM WND DMG REPORT FROM 3 E LORIMOR. LARGE MAPLE TREE LOSS OF LARGE LIMBS, LARGE LIMB SNAPPED.
Jul 30, 9:57 PM CDT	HAIL 1.75	2 W Murray, IA	TRAINED SPOTTER REPORTS WIND DRIVEN GOLF BALL SIZED HAIL AND HEAVY RAINFALL.

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
Jul 30, 8:47 PM CDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 2.6 hours before the alert went out and 197 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: 2669 J/kg
Mixed-layer CIN: -3 J/kg
Mixed-layer LCL: 967 m above ground
0-6 km bulk shear: 40 kt
0-1 km storm-relative helicity: 52 m²/s²
0-3 km storm-relative helicity: 279 m²/s²
Significant tornado parameter: 3.4
Supercell composite: 19.5

Open this sounding in Storm Lab

The text

As transmitted.

063 
WUUS53 KDMX 310238
SVRDMX
IAC039-121-175-310315-
/O.NEW.KDMX.SV.W.0081.210731T0238Z-210731T0315Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Des Moines IA
938 PM CDT Fri Jul 30 2021

The National Weather Service in Des Moines  has issued a

* Severe Thunderstorm Warning for...
  South central Madison County in south central Iowa...
  Northeastern Union County in south central Iowa...
  Northwestern Clarke County in south central Iowa...

* Until 1015 PM CDT.

* At 938 PM CDT, a severe thunderstorm was located 13 miles south of
  Winterset, moving southeast at 25 mph.

  HAZARD...Quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Damage to vehicles is expected.

* This severe thunderstorm will remain over mainly rural areas of
  south central Madison, northeastern Union and northwestern Clarke
  Counties, including the following locations... Murray, Murray
  Roadside Rest Area, Lorimor and Thayer.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4117 9414 4123 9399 4106 9381 4096 9406
TIME...MOT...LOC 0238Z 328DEG 23KT 4116 9403 

HAIL...1.00IN
WIND...<50MPH
 
$$

Ansorge

2 follow-up statements

153 
WWUS53 KDMX 310248
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
948 PM CDT Fri Jul 30 2021

IAC121-310258-
/O.CAN.KDMX.SV.W.0081.000000T0000Z-210731T0315Z/
Madison IA-
948 PM CDT Fri Jul 30 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTH CENTRAL MADISON 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 200 AM CDT for
south central Iowa.

LAT...LON 4116 9413 4116 9391 4106 9381 4096 9406
TIME...MOT...LOC 0248Z 328DEG 23KT 4110 9398 

$$

IAC039-175-310315-
/O.CON.KDMX.SV.W.0081.000000T0000Z-210731T0315Z/
Union IA-Clarke IA-
948 PM CDT Fri Jul 30 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1015 PM CDT
FOR NORTHEASTERN UNION AND NORTHWESTERN CLARKE COUNTIES...

At 948 PM CDT, a severe thunderstorm was located 10 miles northwest
of Lakeside Casino, or 11 miles northwest of Osceola, moving
southeast at 25 mph.

HAZARD...Quarter size hail.

SOURCE...Radar indicated.

IMPACT...Damage to vehicles is expected.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4116 9413 4116 9391 4106 9381 4096 9406
TIME...MOT...LOC 0248Z 328DEG 23KT 4110 9398 

HAIL...1.00IN
WIND...<50MPH
 
$$

Ansorge

375 
WWUS53 KDMX 310307
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
1007 PM CDT Fri Jul 30 2021

IAC039-175-310316-
/O.EXP.KDMX.SV.W.0081.000000T0000Z-210731T0315Z/
Union IA-Clarke IA-
1007 PM CDT Fri Jul 30 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN UNION AND
NORTHWESTERN CLARKE COUNTIES WILL EXPIRE AT 1015 PM CDT...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning will be allowed to expire. Another severe 
thunderstorm warning continues for southwestern and portions of 
south central Clarke County until 1045 PM.

A Severe Thunderstorm Watch remains in effect until 200 AM CDT for
south central Iowa.

LAT...LON 4116 9413 4116 9391 4106 9381 4096 9406
TIME...MOT...LOC 0306Z 328DEG 23KT 4101 9390 

$$

Ansorge

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 30, 9:52 PM CDT	Severe Thunderstorm Warning	DMX	Clarke, Decatur, Ringgold, Union	34 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.