Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 90, NWS Quad Cities, IA

August 24, 2021Delaware County, Dubuque County, Iowa; Jo Daviess County, Illinois

NWS Quad Cities, IA issued this severe thunderstorm warning at Aug 24, 2021, 3:42 PM CDT for Delaware County, Dubuque County, Iowa; Jo Daviess County, Illinois. It was in force for 48 min. 9 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
Aug 24, 2021, 3:42 PM CDT (20:42 UTC)
Expired
Aug 24, 2021, 4:30 PM CDT
In force
48 min
Issued by
NWS Quad Cities, IA
Area
Storm-based polygon
Damage threat
Destructive
Hail
1.0 in
Wind
80.0 mph

Counties Delaware County, IA, Dubuque County, IA, Jo Daviess County, IL

The radar

The Quad Cities radar (KDVN), 101 km from the middle of the area, began a volume at 20:46 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

TimeReportWhereRemark
Aug 24, 3:53 PM CDTTSTM WND DMGHopkinton, IASEVERAL LARGE TREES DOWN IN TOWN, TIME ESTIMATED FROM RADAR.
Aug 24, 3:58 PM CDTTSTM WND GST 701 S Dyersville, IA
Aug 24, 3:58 PM CDTHAIL 11 S Dyersville, IA
Aug 24, 4:00 PM CDTTSTM WND DMGWorthington, IALARGE PINE TREE DOWN ACROSS ROAD NEAR TOWN, TIME ESTIMATED FROM RADAR.
Aug 24, 4:00 PM CDTTSTM WND GST 581 S Dyersville, IAMEASURED AT FIRE STATION.
Aug 24, 4:15 PM CDTTSTM WND DMG2 N Bernard, IALATE REPORT - TIME ESTIMATED ... GRAIN BIN AND DETACHED GARAGE DESTROYED.
Aug 24, 4:25 PM CDTTSTM WND GST 501 Se Asbury, IA40 TO 50 MPH GUSTS ESTIMATED.
Aug 24, 4:33 PM CDTHAIL 1Dubuque Regional Arpt, IASOCIAL MEDIA REPORT WITH PICTURE.
Aug 24, 4:36 PM CDTTSTM WND GST 60Dubuque Regional Arpt, 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.

IssuedProductOfficeLasted
Aug 24, 1:52 PM CDTSevere Thunderstorm WatchSPC5 hr

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 8.7 hours before the alert went out and 101 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 2021-08-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1809 joules per kilogram.LCLLFCEL10008507005003002001001 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 2021-08-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 35 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
1809 J/kg
Mixed-layer CIN
-127 J/kg
Mixed-layer LCL
1284 m above ground
0-6 km bulk shear
15 kt
0-1 km storm-relative helicity
35 m²/s²
0-3 km storm-relative helicity
9 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

646 
WUUS53 KDVN 242042
SVRDVN
ILC085-IAC055-061-242130-
/O.NEW.KDVN.SV.W.0090.210824T2042Z-210824T2130Z/

BULLETIN - EAS ACTIVATION REQUESTED
Severe Thunderstorm Warning
National Weather Service Quad Cities IA/IL
342 PM CDT Tue Aug 24 2021

The National Weather Service in the Quad Cities has issued a

* Severe Thunderstorm Warning for...
  Northwestern Jo Daviess County in northwestern Illinois...
  Dubuque County in northeastern Iowa...
  Eastern Delaware County in northeastern Iowa...

* Until 430 PM CDT.

* At 341 PM CDT, severe thunderstorms were located along a line
  extending from near Colesburg to near Earlville to Hopkinton,
  moving east at 40 mph.

  THESE ARE DESTRUCTIVE STORMS FOR eastern Delaware and western 
Dubuque counties!

  HAZARD...80 mph wind gusts and quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Flying debris will be dangerous to those caught without 
           shelter. Mobile homes will be heavily damaged. Expect 
           considerable damage to roofs, windows, and vehicles. 
           Extensive tree damage and power outages are likely.

* Severe thunderstorms will be near...
  Dyersville and New Vienna around 350 PM CDT.
  Worthington and Luxemburg around 355 PM CDT.
  Farley and Holy Cross around 400 PM CDT.

Other locations in the path of these severe thunderstorms include
Epworth, Bankston, Peosta, Rickardsville, Balltown, Dubuque,
Centralia, Bernard, Asbury, Sherrill, Durango and Sageville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Prepare immediately for large hail and damaging winds. People outside
should move immediately to shelter inside a strong building. Stay
away from windows.

Intense thunderstorm lines can produce brief tornadoes and widespread
significant wind damage. Although a tornado is not immediately
likely, it is best to move to an interior room on the lowest floor of
a building. These storms may cause serious injury and significant
property damage.

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

&&

LAT...LON 4264 9071 4254 9064 4251 9064 4251 9051
      4248 9050 4238 9061 4238 9067 4233 9067
      4230 9070 4232 9133 4248 9132 4265 9135
      4265 9090 4268 9089
TIME...MOT...LOC 2041Z 269DEG 33KT 4263 9124 4249 9122 4237 9126 

THUNDERSTORM DAMAGE THREAT...DESTRUCTIVE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...80 MPH

$$

Ervin
5 follow-up statements
728 
WWUS53 KDVN 242052
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
352 PM CDT Tue Aug 24 2021

ILC085-IAC055-061-242130-
/O.CON.KDVN.SV.W.0090.000000T0000Z-210824T2130Z/
Jo Daviess IL-Dubuque IA-Delaware IA-
352 PM CDT Tue Aug 24 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 430 PM CDT
FOR NORTHWESTERN JO DAVIESS...DUBUQUE AND EASTERN DELAWARE
COUNTIES...

At 351 PM CDT, severe thunderstorms were located along a line
extending from near Luxemburg to Dyersville to near Worthington,
moving east at 40 mph.

THESE ARE DESTRUCTIVE STORMS FOR eastern Delaware and western 
Dubuque counties!

HAZARD...80 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Flying debris will be dangerous to those caught without 
         shelter. Mobile homes will be heavily damaged. Expect 
         considerable damage to roofs, windows, and vehicles. 
         Extensive tree damage and power outages are likely.

These severe storms will be near...
  Farley and Luxemburg around 400 PM CDT.

Other locations in the path of these severe thunderstorms include
Epworth, Holy Cross, Bankston, Peosta, Dubuque, Rickardsville,
Centralia, Bernard, Balltown, Asbury, Sherrill, Durango, Sageville,
East Dubuque and Menominee.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Prepare immediately for large hail and damaging winds. People outside
should move to a shelter, inside a strong building and away from
windows.

Intense thunderstorm lines can produce brief tornadoes and widespread
significant wind damage. Although a tornado is not immediately
likely, it is best to move to an interior room on the lowest floor of
a building. These storms may cause serious injury and significant
property damage.

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

&&

LAT...LON 4264 9071 4254 9064 4251 9064 4251 9051
      4248 9050 4238 9061 4238 9067 4230 9070
      4232 9133 4248 9132 4265 9135 4265 9090
      4268 9089
TIME...MOT...LOC 2051Z 268DEG 33KT 4260 9115 4249 9109 4234 9113 

THUNDERSTORM DAMAGE THREAT...DESTRUCTIVE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...80 MPH

$$

Ervin
058 
WWUS53 KDVN 242101
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
401 PM CDT Tue Aug 24 2021

ILC085-IAC055-061-242130-
/O.CON.KDVN.SV.W.0090.000000T0000Z-210824T2130Z/
Jo Daviess IL-Dubuque IA-Delaware IA-
401 PM CDT Tue Aug 24 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 430 PM CDT
FOR NORTHWESTERN JO DAVIESS...DUBUQUE AND EASTERN DELAWARE
COUNTIES...

At 400 PM CDT, severe thunderstorms were located along a line
extending from Luxemburg to near Bankston to near Cascade, moving
east at 40 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.

These severe storms will be near...
  Epworth and Bankston around 405 PM CDT.

Other locations in the path of these severe thunderstorms include
Dubuque, Peosta, Rickardsville, Centralia, Balltown, Asbury, Bernard,
Sherrill, Durango, East Dubuque, Sageville and Menominee.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Prepare immediately for large hail and damaging winds. People outside
should move to a shelter, inside a strong building and away from
windows.

Intense thunderstorm lines can produce brief tornadoes and widespread
significant wind damage. Although a tornado is not immediately
likely, it is best to move to an interior room on the lowest floor of
a building. These storms may cause serious injury and significant
property damage.

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

&&

LAT...LON 4264 9071 4254 9064 4251 9064 4251 9051
      4248 9050 4238 9061 4238 9067 4230 9070
      4231 9098 4232 9133 4248 9132 4265 9128
      4265 9090 4268 9089
TIME...MOT...LOC 2100Z 268DEG 33KT 4260 9105 4249 9100 4234 9104 

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

$$

Ervin
024 
WWUS53 KDVN 242108
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
408 PM CDT Tue Aug 24 2021

ILC085-IAC055-061-242130-
/O.CON.KDVN.SV.W.0090.000000T0000Z-210824T2130Z/
Jo Daviess IL-Dubuque IA-Delaware IA-
408 PM CDT Tue Aug 24 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 430 PM CDT
FOR NORTHWESTERN JO DAVIESS...DUBUQUE AND EASTERN DELAWARE
COUNTIES...

At 408 PM CDT, severe thunderstorms were located along a line
extending from near Holy Cross to near Bankston to near Bernard,
moving east at 40 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.

These severe storms will be near...
  Dubuque, Centralia and Bernard around 415 PM CDT.
  Asbury and Sherrill around 420 PM CDT.

Other locations in the path of these severe thunderstorms include
Durango, East Dubuque, Sageville and Menominee.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Prepare immediately for large hail and damaging winds. People outside
should move to a shelter, inside a strong building and away from
windows.

Intense thunderstorm lines can produce brief tornadoes and widespread
significant wind damage. Although a tornado is not immediately
likely, it is best to move to an interior room on the lowest floor of
a building. These storms may cause serious injury and significant
property damage.

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

&&

LAT...LON 4264 9071 4254 9064 4251 9064 4251 9051
      4248 9050 4238 9061 4238 9067 4230 9070
      4231 9098 4232 9120 4248 9132 4265 9118
      4265 9090 4268 9089
TIME...MOT...LOC 2108Z 268DEG 33KT 4260 9096 4249 9091 4232 9092 

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

$$

Ervin
916 
WWUS53 KDVN 242120
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
420 PM CDT Tue Aug 24 2021

IAC055-242130-
/O.CAN.KDVN.SV.W.0090.000000T0000Z-210824T2130Z/
Delaware IA-
420 PM CDT Tue Aug 24 2021

...THE SEVERE THUNDERSTORM WARNING FOR EASTERN DELAWARE COUNTY IS
CANCELLED...

The storms which prompted the warning have moved out of the warned 
area. Therefore, the warning has been cancelled.

A Severe Thunderstorm Watch remains in effect until 700 PM CDT for
northwestern Illinois...and northeastern and east central Iowa.

LAT...LON 4264 9071 4254 9064 4251 9064 4251 9051
      4248 9050 4238 9061 4238 9067 4230 9070
      4231 9098 4232 9104 4251 9109 4261 9096
      4265 9090 4268 9089
TIME...MOT...LOC 2120Z 268DEG 33KT 4260 9082 4249 9077 4231 9080 

$$

ILC085-IAC061-242130-
/O.CON.KDVN.SV.W.0090.000000T0000Z-210824T2130Z/
Jo Daviess IL-Dubuque IA-
420 PM CDT Tue Aug 24 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 430 PM CDT
FOR NORTHWESTERN JO DAVIESS AND DUBUQUE COUNTIES...

At 420 PM CDT, severe thunderstorms were located along a line
extending from Sherrill to Asbury to Bernard, moving east at 40 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.

These severe storms will be near...
  Dubuque around 425 PM CDT.

Other locations in the path of these severe thunderstorms include
East Dubuque, Sageville and Menominee.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Prepare immediately for large hail and damaging winds. People outside
should move to a shelter, inside a strong building and away from
windows.

Intense thunderstorm lines can produce brief tornadoes and widespread
significant wind damage. Although a tornado is not immediately
likely, it is best to move to an interior room on the lowest floor of
a building. These storms may cause serious injury and significant
property damage.

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

&&

LAT...LON 4264 9071 4254 9064 4251 9064 4251 9051
      4248 9050 4238 9061 4238 9067 4230 9070
      4231 9098 4232 9104 4251 9109 4261 9096
      4265 9090 4268 9089
TIME...MOT...LOC 2120Z 268DEG 33KT 4260 9082 4249 9077 4231 9080 

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

$$

Ervin
436 
WWUS53 KDVN 242131
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
431 PM CDT Tue Aug 24 2021

IAC061-ILC085-242140-
/O.EXP.KDVN.SV.W.0090.000000T0000Z-210824T2130Z/
Jo Daviess IL-Dubuque IA-
431 PM CDT Tue Aug 24 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN JO DAVIESS AND
DUBUQUE COUNTIES HAS EXPIRED...
    
The storms which prompted the warning have moved out of the area.
Therefore, the warning has been allowed to expire.  However gusty
winds and heavy rain are still possible with these thunderstorms.

A warning continues for eastern Dubuque county until 515 pm.

A Severe Thunderstorm Watch remains in effect until 700 PM CDT for
northwestern Illinois...and northeastern and east central Iowa.

LAT...LON 4264 9071 4254 9064 4251 9064 4251 9051
      4248 9050 4238 9061 4238 9067 4230 9070
      4231 9098 4232 9104 4251 9109 4261 9096
      4265 9090 4268 9089
TIME...MOT...LOC 2130Z 269DEG 33KT 4260 9069 4249 9064 4231 9067 

$$

Ervin

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 24, 2:21 PM CDTSevere Thunderstorm WarningDVNBuchanan39 min
Aug 24, 2:49 PM CDTSevere Thunderstorm Warning Considerable damage threatDVNBenton, Buchanan, Delaware, Jones, Linn56 min
Aug 24, 3:03 PM CDTSevere Thunderstorm Warning Destructive damage threatDVNBuchanan, Delaware, Dubuque42 min
Aug 24, 3:38 PM CDTTornado WarningDVNDubuque25 min
Aug 24, 4:07 PM CDTSpecial Weather StatementDVNCedar, Clinton, Jackson, Johnson23 min
Aug 24, 4:17 PM CDTSevere Thunderstorm Warning Considerable damage threatDVNDubuque, Jackson58 min
Aug 24, 4:54 PM CDTSpecial Weather StatementDVNBenton36 min
Aug 24, 5:01 PM CDTSevere Thunderstorm WarningDVNJackson59 min
Aug 24, 5:05 PM CDTSevere Thunderstorm WarningDVNBenton, Iowa40 min
Aug 24, 5:23 PM CDTSevere Thunderstorm WarningDVNClinton, Scott37 min
Aug 24, 5:27 PM CDTSpecial Weather StatementDVNJohnson48 min
Aug 24, 6:07 PM CDTSevere Thunderstorm WarningDVNCedar, Johnson, Linn38 min
Aug 24, 6:49 PM CDTSpecial Weather StatementDVNScott41 min
Aug 24, 5:46 PM CDTSevere Thunderstorm WarningDVNBureau, Henry, Mercer, Rock Island, Whiteside44 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2021Severe Thunderstorm Warnings in Illinois, 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.