Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 90, NWS La Crosse, WI

August 24, 2021Clayton County, Fayette County, Iowa

NWS La Crosse, WI issued this severe thunderstorm warning at Aug 24, 2021, 2:59 PM CDT for Clayton County, Fayette County, Iowa. It was in force for 61 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, 2:59 PM CDT (19:59 UTC)
Expired
Aug 24, 2021, 4:00 PM CDT
In force
61 min
Issued by
NWS La Crosse, WI
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Clayton County, IA, Fayette County, IA

The radar

The La Crosse radar (KARX), 118 km from the middle of the area, began a volume at 20:02 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, 3:26 PM CDTTSTM WND GST 501 S Strawberry Point, 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, 8.0 hours before the alert went out and 140 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.

813 
WUUS53 KARX 241959
SVRARX
IAC043-065-242100-
/O.NEW.KARX.SV.W.0090.210824T1959Z-210824T2100Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service La Crosse WI
259 PM CDT Tue Aug 24 2021

The National Weather Service in La Crosse has issued a

* Severe Thunderstorm Warning for...
  Clayton County in northeastern Iowa...
  Southeastern Fayette County in northeastern Iowa...

* Until 400 PM CDT.

* At 259 PM CDT, severe thunderstorms were located along a line
  extending from near Fayette to Stanley, moving east at 40 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...
  Guttenberg, Elkader, Strawberry Point, Edgewood, Garnavillo,
  Arlington, Volga, Wadena, North Buena Vista, Garber, Osterdock,
  Elkport, Millville, Camp C.S. Klaus, Mederville, Highways 3 And
  187, Turkey River, Bixby State Park, Highway 13 And County C 24 and
  Fairview.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4264 9172 4291 9168 4289 9111 4288 9110
      4283 9110 4283 9108 4275 9107 4269 9097
      4268 9090 4265 9090
TIME...MOT...LOC 1959Z 272DEG 34KT 4290 9177 4265 9178 

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

$$

Kurz
3 follow-up statements
674 
WWUS53 KARX 242023
SVSARX

Severe Weather Statement
National Weather Service La Crosse WI
323 PM CDT Tue Aug 24 2021

IAC065-242032-
/O.CAN.KARX.SV.W.0090.000000T0000Z-210824T2100Z/
Fayette IA-
323 PM CDT Tue Aug 24 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN FAYETTE 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
northeastern Iowa...and southwestern Wisconsin.

LAT...LON 4264 9155 4290 9151 4289 9111 4288 9110
      4283 9110 4283 9108 4275 9107 4269 9097
      4268 9090 4265 9090
TIME...MOT...LOC 2022Z 272DEG 34KT 4288 9148 4264 9150 

$$

IAC043-242100-
/O.CON.KARX.SV.W.0090.000000T0000Z-210824T2100Z/
Clayton IA-
323 PM CDT Tue Aug 24 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 400 PM CDT
FOR SOUTHERN CLAYTON COUNTY...

At 322 PM CDT, severe thunderstorms were located along a line
extending from near Elkader to near Strawberry Point, moving east at
40 mph.

HAZARD...60 mph wind gusts and penny size hail.

SOURCE...Radar indicated.

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

Locations impacted include...
Guttenberg, Elkader, Strawberry Point, Edgewood, Garnavillo, North
Buena Vista, Garber, Osterdock, Elkport, Millville, Camp C.S. Klaus,
Mederville, Turkey River, Bixby State Park, Highway 13 And County C
24, Fairview, Osborne, Littleport, Lock And Dam 10 and Wood.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Continuous cloud to ground lightning is occurring with these storms.
Move indoors immediately.

&&

LAT...LON 4264 9155 4290 9151 4289 9111 4288 9110
      4283 9110 4283 9108 4275 9107 4269 9097
      4268 9090 4265 9090
TIME...MOT...LOC 2022Z 272DEG 34KT 4288 9148 4264 9150 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Kurz
161 
WWUS53 KARX 242039
SVSARX

Severe Weather Statement
National Weather Service La Crosse WI
339 PM CDT Tue Aug 24 2021

IAC043-242100-
/O.CON.KARX.SV.W.0090.000000T0000Z-210824T2100Z/
Clayton IA-
339 PM CDT Tue Aug 24 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 400 PM CDT
FOR SOUTHEASTERN CLAYTON COUNTY...

At 338 PM CDT, severe thunderstorms were located along a line
extending from Garnavillo to near Greeley, moving east at 40 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
Guttenberg, Edgewood, Garnavillo, Colesburg, North Buena Vista,
Garber, Osterdock, Elkport, Millville, Lock And Dam 10, Camp C.S.
Klaus, Wood, Motor, Communia, Clayton Center, Turkey River, County
Roads X 47 And C 7 X, Bixby State Park, Fairview and Littleport.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4264 9141 4289 9135 4289 9111 4288 9110
      4283 9110 4283 9108 4275 9107 4269 9097
      4268 9090 4265 9090
TIME...MOT...LOC 2038Z 272DEG 34KT 4287 9127 4263 9129 

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

$$

Kurz
330 
WWUS53 KARX 242054
SVSARX

Severe Weather Statement
National Weather Service La Crosse WI
354 PM CDT Tue Aug 24 2021

IAC043-242103-
/O.EXP.KARX.SV.W.0090.000000T0000Z-210824T2100Z/
Clayton IA-
354 PM CDT Tue Aug 24 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN CLAYTON COUNTY
WILL EXPIRE AT 400 PM CDT...
            
The storms which prompted the warning are weakening below severe 
limits, and no longer expected to pose an immediate threat to life 
or property. Therefore, the warning will be allowed to expire.

A Severe Thunderstorm Watch remains in effect until 700 PM CDT for
northeastern Iowa...and southwestern Wisconsin.

LAT...LON 4264 9141 4289 9135 4289 9111 4288 9110
      4283 9110 4283 9108 4275 9107 4269 9097
      4268 9090 4265 9090
TIME...MOT...LOC 2053Z 272DEG 34KT 4287 9109 4263 9111 

$$

Kurz

The office that day

Everything else NWS La Crosse, WI issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 24, 12:35 PM CDTSpecial Weather StatementARXMitchell55 min
Aug 24, 12:38 PM CDTSpecial Weather StatementARXFloyd67 min
Aug 24, 1:29 PM CDTSpecial Weather StatementARXHoward, Mitchell46 min
Aug 24, 1:43 PM CDTSevere Thunderstorm WarningARXChickasaw, Floyd47 min
Aug 24, 1:48 PM CDTSpecial Weather StatementARXChickasaw27 min
Aug 24, 2:15 PM CDTSevere Thunderstorm WarningARXChickasaw, Fayette60 min
Aug 24, 3:12 PM CDTSpecial Weather StatementARXFayette18 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.