Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 35, NWS Des Moines, IA

June 20, 2021Bremer County, Butler County, Franklin County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Jun 20, 2021, 4:54 PM CDT for Bremer County, Butler County, Franklin County, Iowa. It was in force for 51 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, 4:54 PM CDT (21:54 UTC)
Expired
Jun 20, 2021, 5:45 PM CDT
In force
51 min
Issued by
NWS Des Moines, IA
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Bremer County, IA, Butler County, IA, Franklin County, IA

The radar

The Des Moines radar (KDMX), 137 km from the middle of the area, began a volume at 21:54 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.

IssuedProductOfficeLasted
Jun 20, 1:42 PM CDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 9.9 hours before the alert went out and 233 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-pSkew-T log-p diagram, Davenport, at 12:00Z on 2021-06-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Davenport, at 12:00Z on 2021-06-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 102 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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.

594 
WUUS53 KDMX 202154
SVRDMX
IAC017-023-069-202245-
/O.NEW.KDMX.SV.W.0035.210620T2154Z-210620T2245Z/

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

The National Weather Service in Des Moines  has issued a

* Severe Thunderstorm Warning for...
  Western Bremer County in northeastern Iowa...
  Northeastern Franklin County in north central Iowa...
  Butler County in north central Iowa...

* Until 545 PM CDT.

* At 454 PM CDT, a severe thunderstorm was located 8 miles southwest
  of Greene, or 9 miles northwest of Allison, moving east at 55 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...
  Greene around 500 PM CDT.
  Allison around 505 PM CDT.
  Clarksville around 510 PM CDT.

Other locations in the path of this severe thunderstorm include Shell
Rock and Waverly.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4273 9319 4291 9317 4291 9235 4264 9235
TIME...MOT...LOC 2154Z 275DEG 47KT 4283 9295 

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

REV
3 follow-up statements
785 
WWUS53 KDMX 202213
SVSDMX

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

IAC017-023-069-202245-
/O.CON.KDMX.SV.W.0035.000000T0000Z-210620T2245Z/
Bremer IA-Franklin IA-Butler IA-
513 PM CDT Sun Jun 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 545 PM CDT
FOR WESTERN BREMER...EASTERN FRANKLIN AND BUTLER COUNTIES...

At 513 PM CDT, a severe thunderstorm was located near Clarksville, or
7 miles northwest of Waverly, moving east at 45 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...
  Waverly.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4271 9303 4291 9302 4291 9235 4264 9235
TIME...MOT...LOC 2213Z 273DEG 39KT 4279 9259 

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

REV
314 
WWUS53 KDMX 202227
SVSDMX

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

IAC017-023-069-202245-
/O.CON.KDMX.SV.W.0035.000000T0000Z-210620T2245Z/
Bremer IA-Franklin IA-Butler IA-
527 PM CDT Sun Jun 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 545 PM CDT
FOR WESTERN BREMER...EASTERN FRANKLIN AND BUTLER COUNTIES...

At 527 PM CDT, a severe thunderstorm was located near Waverly, 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.

Locations impacted include...
Waverly, Allison, Clarksville, Shell Rock, Greene, Janesville,
Dumont, Plainfield, Bristow, Aredale, Allison Municipal Airport and
Waverly Municipal Airport.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4271 9303 4291 9302 4291 9235 4264 9235
TIME...MOT...LOC 2227Z 273DEG 31KT 4278 9247 

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

REV
662 
WWUS53 KDMX 202239
SVSDMX

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

IAC017-023-069-202249-
/O.EXP.KDMX.SV.W.0035.000000T0000Z-210620T2245Z/
Bremer IA-Franklin IA-Butler IA-
539 PM CDT Sun Jun 20 2021

...THE SEVERE THUNDERSTORM WARNING FOR WESTERN BREMER...EASTERN
FRANKLIN AND BUTLER COUNTIES WILL EXPIRE AT 545 PM CDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning will be allowed to expire.  However gusty
winds and heavy rain are still possible with this thunderstorm.

A Severe Thunderstorm Watch remains in effect until 900 PM CDT for
north central and northeastern Iowa.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
Des Moines .

LAT...LON 4271 9303 4291 9302 4291 9235 4264 9235
TIME...MOT...LOC 2239Z 275DEG 47KT 4277 9229 

$$

REV

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 20, 3:38 PM CDTSpecial Weather StatementDMXDallas37 min
Jun 20, 4:20 PM CDTSevere Thunderstorm WarningDMXClarke, Madison, Union55 min
Jun 20, 4:47 PM CDTSevere Thunderstorm WarningDMXJasper43 min
Jun 20, 4:53 PM CDTSevere Thunderstorm WarningDMXClarke, Decatur, Ringgold, Union52 min
Jun 20, 5:33 PM CDTSevere Thunderstorm WarningDMXJasper, Poweshiek42 min
Jun 20, 5:35 PM CDTSevere Thunderstorm WarningDMXClarke, Decatur, Lucas, Wayne40 min
Jun 20, 5:55 PM CDTSevere Thunderstorm WarningDMXJasper, Mahaska, Marion50 min
Jun 20, 5:59 PM CDTSevere Thunderstorm WarningDMXDecatur, Wayne46 min
Jun 20, 6:04 PM CDTTornado WarningDMXDecatur26 min
Jun 20, 6:13 PM CDTSevere Thunderstorm WarningDMXPoweshiek62 min
Jun 20, 6:15 PM CDTSevere Thunderstorm WarningDMXDecatur, Wayne30 min
Jun 20, 6:20 PM CDTSevere Thunderstorm WarningDMXBlack Hawk55 min
Jun 20, 6:37 PM CDTTornado WarningDMXMahaska, Marion23 min
Jun 20, 6:43 PM CDTSevere Thunderstorm WarningDMXDecatur, Wayne47 min
Jun 20, 6:59 PM CDTTornado WarningDMXMahaska, Marion31 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2021Every 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.