Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 105, NWS Quad Cities, IA

August 26, 2021Jefferson County, Washington County, Iowa

NWS Quad Cities, IA issued this severe thunderstorm warning at Aug 26, 2021, 11:39 PM CDT for Jefferson County, Washington County, Iowa. It was in force for 31 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: Aug 26, 2021, 11:39 PM CDT (04:39 UTC)
Expired: Aug 27, 2021, 12:10 AM CDT
In force: 31 min
Issued by: NWS Quad Cities, IA
Area: Storm-based polygon
Damage threat: Considerable
Hail: 1.0 in
Wind: 70.0 mph

Counties Jefferson County, IA, Washington County, IA

The radar

The Quad Cities radar (KDVN), 126 km from the middle of the area, began a volume at 04:43 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 nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 4.7 hours before the alert went out and 133 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: 673 J/kg
Mixed-layer CIN: -189 J/kg
Mixed-layer LCL: 1469 m above ground
0-6 km bulk shear: 33 kt
0-1 km storm-relative helicity: -106 m²/s²
0-3 km storm-relative helicity: -64 m²/s²
Significant tornado parameter: -0.0
Supercell composite: -1.7

Open this sounding in Storm Lab

The text

As transmitted.

628 
WUUS53 KDVN 270439
SVRDVN
IAC101-183-270530-
/O.NEW.KDVN.SV.W.0105.210827T0439Z-210827T0530Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Quad Cities IA/IL
1139 PM CDT Thu Aug 26 2021

The National Weather Service in the Quad Cities has issued a

* Severe Thunderstorm Warning for...
  Southwestern Washington County in southeastern Iowa...
  Jefferson County in southeastern Iowa...

* Until 1230 AM CDT.

* At 1138 PM CDT, a severe thunderstorm was located near Pleasant
  Plain, or 7 miles north of Fairfield, moving southeast at 20 mph.

  HAZARD...70 mph wind gusts and quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Hail damage to vehicles is expected. Expect considerable 
           tree damage. Wind damage is also likely to mobile homes, 
           roofs, and outbuildings.

* This severe thunderstorm will be near...
  Pleasant Plain around 1145 PM CDT.
  Brighton around 1150 PM CDT.

Other locations in the path of this severe thunderstorm include
Lockridge.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Continuous cloud to ground lightning is occurring with this storm.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4116 9211 4116 9195 4117 9194 4125 9194
      4124 9172 4091 9172 4098 9210
TIME...MOT...LOC 0438Z 298DEG 18KT 4111 9195 

THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...OBSERVED
MAX HAIL SIZE...1.00 IN
WIND THREAT...OBSERVED
MAX WIND GUST...70 MPH

$$

Gibbs

3 follow-up statements

095 
WWUS53 KDVN 270445
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
1145 PM CDT Thu Aug 26 2021

IAC101-183-270530-
/O.CON.KDVN.SV.W.0105.000000T0000Z-210827T0530Z/
Washington IA-Jefferson IA-
1145 PM CDT Thu Aug 26 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1230 AM CDT
FOR SOUTHWESTERN WASHINGTON AND NORTHERN JEFFERSON COUNTIES...

At 1145 PM CDT, a severe thunderstorm was located near Pleasant
Plain, or 8 miles northeast of Fairfield, moving east at 20 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 storm will be near...
  Brighton around 1150 PM CDT.

Other locations in the path of this severe thunderstorm include
Coppock.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Continuous cloud to ground lightning is occurring with this storm.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4116 9211 4116 9195 4117 9194 4125 9194
      4124 9172 4100 9172 4106 9210
TIME...MOT...LOC 0445Z 289DEG 19KT 4111 9188 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...OBSERVED
MAX WIND GUST...60 MPH

$$

Gibbs

320 
WWUS53 KDVN 270457
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
1157 PM CDT Thu Aug 26 2021

IAC101-183-270530-
/O.CON.KDVN.SV.W.0105.000000T0000Z-210827T0530Z/
Washington IA-Jefferson IA-
1157 PM CDT Thu Aug 26 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1230 AM CDT
FOR SOUTHWESTERN WASHINGTON AND NORTHEASTERN JEFFERSON COUNTIES...

At 1157 PM CDT, a severe thunderstorm was located near Pleasant
Plain, or 11 miles northeast of Fairfield, moving east at 20 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...
  Coppock.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Continuous cloud to ground lightning is occurring with this storm.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4116 9195 4117 9194 4124 9194 4124 9172
      4104 9172 4109 9206 4116 9205
TIME...MOT...LOC 0457Z 282DEG 16KT 4112 9180 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Gibbs

245 
WWUS53 KDVN 270510
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
1210 AM CDT Fri Aug 27 2021

IAC101-183-270520-
/O.CAN.KDVN.SV.W.0105.000000T0000Z-210827T0530Z/
Washington IA-Jefferson IA-
1210 AM CDT Fri Aug 27 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN WASHINGTON AND
NORTHEASTERN JEFFERSON COUNTIES IS CANCELLED...
                
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 has been cancelled.

LAT...LON 4116 9195 4117 9194 4124 9194 4124 9172
      4104 9172 4109 9206 4116 9205
TIME...MOT...LOC 0508Z 298DEG 18KT 4109 9172 

$$

Ervin

The office that day

Everything else NWS Quad Cities, IA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 26, 8:23 PM CDT	Special Weather Statement	DVN	Benton	52 min
Aug 26, 9:21 PM CDT	Severe Thunderstorm Warning	DVN	Iowa, Keokuk	39 min
Aug 26, 9:58 PM CDT	Severe Thunderstorm Warning Considerable damage threat	DVN	Keokuk	47 min
Aug 26, 10:29 PM CDT	Flash Flood Warning	DVN	Keokuk	4 hr
Aug 26, 10:43 PM CDT	Severe Thunderstorm Warning Considerable damage threat	DVN	Keokuk, Washington	47 min
Aug 26, 10:57 PM CDT	Severe Thunderstorm Warning Considerable damage threat	DVN	Jefferson, Washington	48 min
Aug 26, 11:20 PM CDT	Tornado Warning	DVN	Jefferson, Keokuk	27 min
Aug 27, 1:34 PM CDT	Heat Advisory	DVN	Lee	29 hr
Aug 27, 3:07 PM CDT	Heat Advisory	DVN	Des Moines, Henry, Van Buren	28 hr

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.