Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 96, NWS Quad Cities, IA

August 24, 2021Cedar County, Johnson County, Linn County, Iowa

NWS Quad Cities, IA issued this severe thunderstorm warning at Aug 24, 2021, 6:07 PM CDT for Cedar County, Johnson County, Linn County, Iowa. It was in force for 38 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 24, 2021, 6:07 PM CDT (23:07 UTC)
Expired
Aug 24, 2021, 6:45 PM CDT
In force
38 min
Issued by
NWS Quad Cities, IA
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Cedar County, IA, Johnson County, IA, Linn County, IA

The radar

The Quad Cities radar (KDVN), 70 km from the middle of the area, began a volume at 23:06 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
Aug 24, 1:52 PM CDTSevere Thunderstorm WatchSPC5 hr

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 11.1 hours before the alert went out and 75 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.

453 
WUUS53 KDVN 242307
SVRDVN
IAC031-103-113-242345-
/O.NEW.KDVN.SV.W.0096.210824T2307Z-210824T2345Z/

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

The National Weather Service in the Quad Cities has issued a

* Severe Thunderstorm Warning for...
  Northern Cedar County in east central Iowa...
  Northeastern Johnson County in east central Iowa...
  Southeastern Linn County in east central Iowa...

* Until 645 PM CDT.

* At 607 PM CDT, a severe thunderstorm was located over Mount Vernon,
  or 9 miles west of Mechanicsville, moving east at 50 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...
  Mechanicsville around 620 PM CDT.
  Stanwood around 625 PM CDT.

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 4196 9150 4196 9137 4195 9136 4194 9097
      4176 9101 4186 9151
TIME...MOT...LOC 2307Z 282DEG 44KT 4189 9144 

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

$$

Gibbs
2 follow-up statements
544 
WWUS53 KDVN 242318
SVSDVN

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

IAC103-242327-
/O.CAN.KDVN.SV.W.0096.000000T0000Z-210824T2345Z/
Johnson IA-
618 PM CDT Tue Aug 24 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN JOHNSON 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 700 PM CDT for
east central Iowa.

LAT...LON 4195 9136 4195 9130 4194 9097 4176 9101
      4184 9137 4186 9137 4186 9145 4196 9145
      4196 9137
TIME...MOT...LOC 2317Z 275DEG 28KT 4189 9134 

$$

IAC031-113-242345-
/O.CON.KDVN.SV.W.0096.000000T0000Z-210824T2345Z/
Cedar IA-Linn IA-
618 PM CDT Tue Aug 24 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 645 PM CDT
FOR NORTHERN CEDAR AND SOUTHEASTERN LINN COUNTIES...

At 617 PM CDT, a severe thunderstorm was located near Lisbon, or near
Mechanicsville, moving east at 30 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...
  Mechanicsville around 625 PM CDT.

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

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 4195 9136 4195 9130 4194 9097 4176 9101
      4184 9137 4186 9137 4186 9145 4196 9145
      4196 9137
TIME...MOT...LOC 2317Z 275DEG 28KT 4189 9134 

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

$$

Gibbs
828 
WWUS53 KDVN 242339
SVSDVN

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

IAC031-113-242349-
/O.EXP.KDVN.SV.W.0096.000000T0000Z-210824T2345Z/
Cedar IA-Linn IA-
639 PM CDT Tue Aug 24 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHERN CEDAR AND
SOUTHEASTERN LINN COUNTIES WILL EXPIRE AT 645 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 heavy rain
is still possible with this thunderstorm.

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

LAT...LON 4195 9136 4195 9130 4194 9097 4176 9101
      4184 9137 4186 9137 4186 9145 4196 9145
      4196 9137
TIME...MOT...LOC 2339Z 282DEG 44KT 4184 9101 

$$

Gibbs

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, 3:42 PM CDTSevere Thunderstorm Warning Destructive damage threatDVNDelaware, Dubuque48 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, 6:49 PM CDTSpecial Weather StatementDVNScott41 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.