Alert archive / Iowa / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 87, NWS La Crosse, WI

August 9, 2012Fayette County, Winneshiek County, Iowa

NWS La Crosse, WI issued this severe thunderstorm warning at Aug 9, 2012, 4:49 PM CDT for Fayette County, Winneshiek County, Iowa. It was in force for 56 min. 6 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 9, 2012, 4:49 PM CDT (21:49 UTC)
Expired
Aug 9, 2012, 5:45 PM CDT
In force
56 min
Issued by
NWS La Crosse, WI
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Fayette County, IA, Winneshiek County, IA

The radar

The La Crosse radar (KARX), 94 km from the middle of the area, began a volume at 21:50 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 9, 4:55 PM CDTHAIL 14 E Ridgeway, IADIME TO QUARTER SIZED. ALSO SOME SMALL BRANCHES DOWNED FROM WIND.
Aug 9, 4:56 PM CDTHAIL 1.754 E Ridgeway, IAQUARTER TO GOLFBALL. DENTED CAMPER. WIND ESTIMATED AT 50 MPH WITH LEAVES SPRAYED ONTO SIDE OF HOUSE. NO DAMAGE TO HOME SIDING.
Aug 9, 4:56 PM CDTHAIL 22 W Decorah, IACOURTESY KWWL MEDIA. VERIFIED WITH PICTURE.
Aug 9, 5:05 PM CDTTSTM WND GST 70Conover, IA
Aug 9, 5:10 PM CDTTSTM WND GST 70Calmar, IACALMAR FIRE DEPARTMENT ESTIMATED A WIND GUST OF 70 MILES PER HOUR.
Aug 9, 5:10 PM CDTHAIL 12 Ne Calmar, IACOOPERATIVE OBSERVER MEASURED UP TO QUARTER SIZE HAIL. DRIFTS OF HAIL IN ROAD DITCH AND THE CORN WAS STRIPPED OF THE LEAVES WITH STALKS AND EARS LEFT.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 9.8 hours before the alert went out and 195 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 2012-08-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 351 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 2012-08-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 83 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
351 J/kg
Mixed-layer CIN
-94 J/kg
Mixed-layer LCL
646 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
83 m²/s²
0-3 km storm-relative helicity
130 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.6

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

997 
WUUS53 KARX 092149
SVRARX
IAC065-191-092245-
/O.NEW.KARX.SV.W.0087.120809T2149Z-120809T2245Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE LA CROSSE WI
449 PM CDT THU AUG 9 2012

THE NATIONAL WEATHER SERVICE IN LA CROSSE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHERN FAYETTE COUNTY IN NORTHEAST IOWA...
  WINNESHIEK COUNTY IN NORTHEAST IOWA...

* UNTIL 545 PM CDT

* AT 446 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM LOCATED NEAR STATE ROAD 9 AND 245TH STREET...OR
  6 MILES WEST OF DECORAH...MOVING SOUTH AT 40 MPH. THIS STORM CAN
  PRODUCE QUARTER SIZE HAIL AND DAMAGING WINDS IN EXCESS OF 60       
  MPH.   

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  CONOVER AND GLENWOOD CHURCH AROUND 455 PM...
  CALMAR AND SPILLVILLE AROUND 500 PM...
  FORT ATKINSON AND COUNTY ROAD W 46 AND CENTENNIAL ROAD AROUND 505
  PM...
  OSSIAN AND WAUCOMA AROUND 510 PM...
  ELDORADO AND CASTALIA AROUND 515 PM...
  COUNTY ROADS W 42 AND B 40 AND DOUGLAS AROUND 520 PM...
  WEST UNION AROUND 525 PM...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IF YOU ARE IN THE PATH OF THIS STORM...PREPARE IMMEDIATELY FOR LARGE
HAIL AND DAMAGING WINDS. SEEK SHELTER NOW INSIDE A STURDY STRUCTURE
AND STAY AWAY FROM WINDOWS.

&&

LAT...LON 4290 9160 4287 9202 4340 9206 4341 9164
TIME...MOT...LOC 2149Z 343DEG 33KT 4330 9189
WIND...HAIL 60MPH 1.00IN

$$

JW
3 follow-up statements
657 
WWUS53 KARX 092218
SVSARX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
518 PM CDT THU AUG 9 2012

IAC065-191-092245-
/O.CON.KARX.SV.W.0087.000000T0000Z-120809T2245Z/
FAYETTE IA-WINNESHIEK IA-
518 PM CDT THU AUG 9 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR SOUTHERN
WINNESHIEK AND NORTHERN FAYETTE COUNTIES UNTIL 545 PM CDT...

LOCAL LAW ENFORCEMENT OFFICIALS REPORTED WINDS OF 70 MPH NEAR 
CONOVER AT 505 PM. 

AT 512 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM LOCATED NEAR FESTINA...OR 10 MILES NORTH OF WEST
UNION...MOVING SOUTH AT 40 MPH. THIS STORM CAN PRODUCE QUARTER SIZE
HAIL AND DAMAGING WINDS IN EXCESS OF 60 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  WEST UNION AND CLERMONT AROUND 525 PM...
  ELGIN AND BRAINARD AROUND 530 PM...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IF YOU ARE IN THE PATH OF THIS STORM...PREPARE IMMEDIATELY FOR LARGE
HAIL AND DAMAGING WINDS. SEEK SHELTER NOW INSIDE A STURDY STRUCTURE
AND STAY AWAY FROM WINDOWS.

&&

LAT...LON 4287 9202 4320 9202 4322 9164 4294 9161
      4290 9161
TIME...MOT...LOC 2216Z 343DEG 33KT 4306 9179
WIND...HAIL 60MPH 1.00IN

$$

JW
906 
WWUS53 KARX 092234
SVSARX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
534 PM CDT THU AUG 9 2012

IAC191-092243-
/O.CAN.KARX.SV.W.0087.000000T0000Z-120809T2245Z/
WINNESHIEK IA-
534 PM CDT THU AUG 9 2012

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN WINNESHIEK COUNTY IS
CANCELLED...

THE STORM WHICH PROMPTED THE WARNING HAS MOVED OUT OF THE WARNED 
AREA.

LAT...LON 4288 9199 4303 9196 4306 9162 4294 9161
      4290 9161
TIME...MOT...LOC 2233Z 343DEG 33KT 4291 9173

$$

IAC065-092245-
/O.CON.KARX.SV.W.0087.000000T0000Z-120809T2245Z/
FAYETTE IA-
534 PM CDT THU AUG 9 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR NORTHERN
FAYETTE COUNTY UNTIL 545 PM CDT...

THIS STORM HAS A HISTORY OF PRODUCING WIND GUSTS OF 70 MPH AND 
QUARTER SIZE HAIL. 

AT 529 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM LOCATED NEAR BRAINARD...OR NEAR WEST UNION...
MOVING SOUTH AT 40 MPH. THIS STORM CAN PRODUCE PENNY SIZE HAIL AND
DAMAGING WINDS IN EXCESS OF 60 MPH.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IF YOU ARE IN THE PATH OF THIS STORM...PREPARE IMMEDIATELY FOR
DAMAGING WINDS AND SMALL HAIL. SEEK SHELTER NOW INSIDE A STURDY
STRUCTURE AND STAY AWAY FROM WINDOWS.

&&

LAT...LON 4288 9199 4303 9196 4306 9162 4294 9161
      4290 9161
TIME...MOT...LOC 2233Z 343DEG 33KT 4291 9173
WIND...HAIL 60MPH 0.75IN

$$

JW
880 
WWUS53 KARX 092240
SVSARX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
540 PM CDT THU AUG 9 2012

IAC065-092250-
/O.EXP.KARX.SV.W.0087.000000T0000Z-120809T2245Z/
FAYETTE IA-
540 PM CDT THU AUG 9 2012

...THE SEVERE THUNDERSTORM WARNING FOR NORTHERN FAYETTE COUNTY WILL
EXPIRE AT 545 PM CDT...

THE STORM WHICH PROMPTED THE WARNING HAS WEAKENED AND MOVED OUT OF
THE WARNED AREA.

CONDITIONS REMAIN FAVORABLE FOR ADDITIONAL STRONG TO SEVERE 
THUNDERSTORMS. BE PREPARED TO SEEK SHELTER IF A WARNING IS ISSUED. 

LAT...LON 4288 9199 4303 9196 4306 9162 4294 9161
      4290 9161
TIME...MOT...LOC 2240Z 343DEG 33KT 4285 9170

$$

JW

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 8, 7:08 PM CDTSevere Thunderstorm WarningARXChickasaw, Howard52 min
Aug 9, 4:55 PM CDTTornado WarningARXFayette, Winneshiek20 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2012Every severe thunderstorm warning in 2012

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.