Alert archive / Illinois / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 94, NWS Quad Cities, IA

August 24, 20214 counties in Illinois; Clinton County, Scott County, Iowa

NWS Quad Cities, IA issued this severe thunderstorm warning at Aug 24, 2021, 5:23 PM CDT for 4 counties in Illinois; Clinton County, Scott County, Iowa. It was in force for 37 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
Aug 24, 2021, 5:23 PM CDT (22:23 UTC)
Expired
Aug 24, 2021, 6:00 PM CDT
In force
37 min
Issued by
NWS Quad Cities, IA
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Clinton County, IA, Scott County, IA, Carroll County, IL, Henry County, IL, Rock Island County, IL, Whiteside County, IL

The radar

The Quad Cities radar (KDVN), 40 km from the middle of the area, began a volume at 22:24 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, 5:24 PM CDTTSTM WND GST 48Davenport Municipality, IAASOS STATION KDVN DAVENPORT ARPT.

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, 10.4 hours before the alert went out and 34 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.

659 
WUUS53 KDVN 242223
SVRDVN
ILC015-073-161-195-IAC045-163-242300-
/O.NEW.KDVN.SV.W.0094.210824T2223Z-210824T2300Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Quad Cities IA/IL
523 PM CDT Tue Aug 24 2021

The National Weather Service in the Quad Cities has issued a

* Severe Thunderstorm Warning for...
  Northeastern Rock Island County in northwestern Illinois...
  Whiteside County in northwestern Illinois...
  Northwestern Henry County in northwestern Illinois...
  Southeastern Carroll County in northwestern Illinois...
  Scott County in east central Iowa...
  Eastern Clinton County in east central Iowa...

* Until 600 PM CDT.

* At 522 PM CDT, severe thunderstorms were located along a line
  extending from near Fairhaven to Garden Plain to Davenport, moving
  southeast at 40 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Trained weather spotters.

  IMPACT...Expect damage to roofs, siding, and trees.

* Severe thunderstorms will be near...
  Erie, Fairhaven, Chadwick and Argo Fay around 530 PM CDT.
  Morrison, Milledgeville and Coleta around 535 PM CDT.
  Prophetstown, Rapids City and Lyndon around 540 PM CDT.

Other locations in the path of these severe thunderstorms include
Cleveland, Osborn, Emerson, Rock Falls and Sterling.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Wind damage with these storms will occur before any rain or
lightning. Do not wait for the sound of thunder before taking cover.
SEEK SHELTER IMMEDIATELY inside a sturdy structure and stay away from
windows.

&&

LAT...LON 4145 9027 4147 9078 4163 9071 4203 9043
      4203 9029 4201 8969 4193 8969 4193 8963
      4170 8963
TIME...MOT...LOC 2222Z 292DEG 34KT 4198 8997 4177 9014 4154 9057 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Ervin
3 follow-up statements
387 
WWUS53 KDVN 242231 RRA
SVSDVN

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

ILC015-073-161-195-IAC045-163-242300-
/O.CON.KDVN.SV.W.0094.000000T0000Z-210824T2300Z/
Rock Island IL-Whiteside IL-Henry IL-Carroll IL-Scott IA-Clinton IA-
531 PM CDT Tue Aug 24 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 600 PM CDT
FOR NORTHEASTERN ROCK ISLAND...WHITESIDE...NORTHWESTERN HENRY...
SOUTHEASTERN CARROLL...SCOTT AND EASTERN CLINTON COUNTIES...

At 531 PM CDT, severe thunderstorms were located along a line
extending from near Fairhaven to near Erie to Riverdale, moving east
at 40 mph.

HAZARD...60 mph wind gusts.

SOURCE...Trained weather spotters.

IMPACT...Expect damage to roofs, siding, and trees.

These severe storms will be near...
  Morrison, Erie, Fairhaven and Chadwick around 535 PM CDT.
  Prophetstown, Milledgeville, Rapids City, Lyndon and Coleta around 
  540 PM CDT.

Other locations in the path of these severe thunderstorms include
Osborn, Emerson and Sterling.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Wind damage with these storms will occur before any rain or
lightning. Do not wait for the sound of thunder before taking cover.
SEEK SHELTER IMMEDIATELY inside a sturdy structure and stay away from
windows.

&&

LAT...LON 4145 9027 4147 9078 4163 9071 4203 9043
      4203 9029 4201 8969 4193 8969 4193 8963
      4170 8963
TIME...MOT...LOC 2231Z 292DEG 34KT 4195 8987 4174 9004 4151 9047 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Ervin
744 
WWUS53 KDVN 242237
SVSDVN

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

ILC015-073-161-195-IAC045-163-242300-
/O.CON.KDVN.SV.W.0094.000000T0000Z-210824T2300Z/
Rock Island IL-Whiteside IL-Henry IL-Carroll IL-Scott IA-Clinton IA-
537 PM CDT Tue Aug 24 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 600 PM CDT
FOR NORTHEASTERN ROCK ISLAND...WHITESIDE...NORTHWESTERN HENRY...
SOUTHEASTERN CARROLL...CENTRAL SCOTT AND SOUTHEASTERN CLINTON
COUNTIES...

At 537 PM CDT, severe thunderstorms were located along a line
extending from Coleta to near Lyndon to Silvis, moving east at 40
mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, and trees.

These severe storms will be near...
  Morrison, Prophetstown, Milledgeville, Lyndon and Coleta around 
  540 PM CDT.
  Emerson around 545 PM CDT.

Other locations in the path of these severe thunderstorms include
Sterling.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Wind damage with these storms will occur before any rain or
lightning. Do not wait for the sound of thunder before taking cover.
SEEK SHELTER IMMEDIATELY inside a sturdy structure and stay away from
windows.

&&

LAT...LON 4145 9027 4147 9078 4163 9071 4184 9025
      4202 9004 4201 8969 4193 8969 4193 8963
      4170 8963
TIME...MOT...LOC 2237Z 292DEG 34KT 4193 8980 4172 8997 4149 9040 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Ervin
360 
WWUS53 KDVN 242253
SVSDVN

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

IAC045-163-ILC015-073-161-195-242302-
/O.EXP.KDVN.SV.W.0094.000000T0000Z-210824T2300Z/
Rock Island IL-Whiteside IL-Henry IL-Carroll IL-Scott IA-Clinton IA-
553 PM CDT Tue Aug 24 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN ROCK ISLAND...
WHITESIDE...NORTHWESTERN HENRY...SOUTHEASTERN CARROLL...CENTRAL SCOTT
AND SOUTHEASTERN CLINTON COUNTIES WILL EXPIRE AT 600 PM CDT...
    
The storms which prompted the warning have weakened below severe
limits, and have exited the warned area. Therefore, the warning will
be allowed to expire.  However gusty winds and heavy rain are still
possible with these thunderstorms.

This warning was issued primarly for the damaging outflow winds 
ahead of the storms.  There will be additional thunderstorms behind 
this initial surge, that do not produce strong winds. 

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

LAT...LON 4145 9027 4147 9078 4163 9071 4184 9025
      4202 9004 4201 8969 4193 8969 4193 8963
      4170 8963
TIME...MOT...LOC 2252Z 292DEG 34KT 4188 8963 4167 8980 4144 9023 

$$

Ervin

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 24, 3:42 PM CDTSevere Thunderstorm Warning Destructive damage threatDVNJo Daviess48 min
Aug 24, 4:17 PM CDTSevere Thunderstorm Warning Considerable damage threatDVNJo Daviess, Stephenson58 min
Aug 24, 5:01 PM CDTSevere Thunderstorm WarningDVNCarroll, Jo Daviess, Stephenson59 min
Aug 24, 5:46 PM CDTSevere Thunderstorm WarningDVNBureau, Henry, Mercer, Rock Island, Whiteside44 min
Aug 24, 6:49 PM CDTSpecial Weather StatementDVNRock Island41 min
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, 4:54 PM CDTSpecial Weather StatementDVNBenton36 min
Aug 24, 5:05 PM CDTSevere Thunderstorm WarningDVNBenton, Iowa40 min
Aug 24, 5:27 PM CDTSpecial Weather StatementDVNJohnson48 min
Aug 24, 6:07 PM CDTSevere Thunderstorm WarningDVNCedar, Johnson, Linn38 min

Nearby

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