Alert archive / Iowa / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 71, NWS La Crosse, WI

July 18, 2012Allamakee County, Winneshiek County, Iowa; Houston County, Minnesota

NWS La Crosse, WI issued this severe thunderstorm warning at Jul 18, 2012, 3:57 PM CDT for Allamakee County, Winneshiek County, Iowa; Houston County, Minnesota. It was in force for 39 min. 2 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: Jul 18, 2012, 3:57 PM CDT (20:57 UTC)
Expired: Jul 18, 2012, 4:36 PM CDT
In force: 39 min
Issued by: NWS La Crosse, WI
Area: Storm-based polygon
Hail: 0.88 in
Wind: 60.0 mph

Counties Allamakee County, IA, Winneshiek County, IA, Houston County, MN

The radar

The La Crosse radar (KARX), 39 km from the middle of the area, began a volume at 20:56 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

Time	Report	Where	Remark
Jul 18, 4:06 PM CDT	TSTM WND DMG	Dorchester, IA	BARN DESTORYED. TIME ESTIMATED FROM RADAR.
Jul 18, 4:15 PM CDT	TSTM WND GST 45	Dorchester, IA	COUPLE OF 6 INCH DIAMETER TREE BRANCHES DOWN.

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.

Issued	Product	Office	Lasted
Jul 18, 12:58 PM CDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 9.0 hours before the alert went out and 221 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1900 J/kg
Mixed-layer CIN: -67 J/kg
Mixed-layer LCL: 1674 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: 35 m²/s²
0-3 km storm-relative helicity: 44 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

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

871 
WUUS53 KARX 182057
SVRARX
IAC005-191-MNC055-182200-
/O.NEW.KARX.SV.W.0071.120718T2057Z-120718T2200Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE LA CROSSE WI
357 PM CDT WED JUL 18 2012

THE NATIONAL WEATHER SERVICE IN LA CROSSE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHERN ALLAMAKEE COUNTY IN NORTHEAST IOWA...
  NORTHEASTERN WINNESHIEK COUNTY IN NORTHEAST IOWA...
  SOUTHERN HOUSTON COUNTY IN SOUTHEAST MINNESOTA...

* UNTIL 500 PM CDT

* AT 352 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR
  THUNDERSTORMS FROM DECORAH TO NEAR HARMONY. THEY WERE MOVING EAST
  AT 20 MPH. THIS STORM CAN PRODUCE NICKEL SIZE HAIL AND DAMAGING
  WINDS IN EXCESS OF 60 MPH.

* THE SEVERE THUNDERSTORMS WILL BE NEAR...
  SPRING GROVE AROUND 400 PM...
  WILLINGTON GROVE AND HANOVER AROUND 410 PM...
  DORCHESTER AROUND 415 PM...
  CALEDONIA AND EITZEN AROUND 425 PM...
  
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

SEVERE THUNDERSTORMS POSE A SIGNIFICANT DANGER TO BOATERS. IF ON AREA
RIVERS OR LAKES...IMMEDIATELY MOVE TO SHORE AND FIND SHELTER.

&&

LAT...LON 4326 9174 4361 9173 4375 9126 4366 9127
      4364 9126 4361 9127 4360 9124 4354 9125
      4347 9122 4345 9123 4344 9122 4338 9121
      4332 9160
TIME...MOT...LOC 2056Z 257DEG 16KT 4351 9166
WIND...HAIL 60MPH 0.88IN

$$

SHEA

3 follow-up statements

049 
WWUS53 KARX 182110
SVSARX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
410 PM CDT WED JUL 18 2012

IAC005-191-MNC055-182200-
/O.CON.KARX.SV.W.0071.000000T0000Z-120718T2200Z/
ALLAMAKEE IA-WINNESHIEK IA-HOUSTON MN-
410 PM CDT WED JUL 18 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR SOUTHERN
HOUSTON...NORTHEASTERN WINNESHIEK AND NORTHERN ALLAMAKEE COUNTIES
UNTIL 500 PM CDT...

AT 406 PM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A LINE 
OF SEVERE THUNDERSTORMS FROM NEAR SPRING GROVE MINNESOTA TO 
DORCHESTER AND OSSIAN IOWA. THEY WERE MOVING EAST AT 30 MPH. THESE 
STORMS CAN PRODUCE PENNY SIZE HAIL AND DAMAGING WINDS IN EXCESS OF 
60 MPH.

* THE SEVERE THUNDERSTORMS WILL BE NEAR...
  CALEDONIA AROUND 415 PM...
  NEW ALBIN AROUND 425 PM...
  BROWNSVILLE AROUND 440 PM...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IF YOU ARE IN THE PATH OF THESE STORMS...PREPARE IMMEDIATELY FOR 
HIGH WINDS. SEEK SHELTER.

SEVERE THUNDERSTORMS POSE A SIGNIFICANT DANGER TO BOATERS. IF ON AREA
RIVERS...IMMEDIATELY MOVE TO SHORE AND FIND SHELTER.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT.

&&

LAT...LON 4326 9174 4361 9173 4375 9126 4366 9127
      4364 9126 4361 9127 4360 9124 4354 9125
      4347 9122 4345 9123 4344 9122 4338 9121
      4332 9160
TIME...MOT...LOC 2108Z 267DEG 26KT 4360 9158 4349 9143
          4336 9141
WIND...HAIL 60MPH 0.75IN

$$

SHEA

799 
WWUS53 KARX 182128
SVSARX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
428 PM CDT WED JUL 18 2012

IAC191-182135-
/O.CAN.KARX.SV.W.0071.000000T0000Z-120718T2200Z/
WINNESHIEK IA-
428 PM CDT WED JUL 18 2012

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

THE LINE OF STORMS WHICH PROMPTED THE WARNING HAS MOVED EAST OF THE 
AREA. 

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 800 PM.

LAT...LON 4350 9161 4357 9158 4375 9126 4361 9127
      4359 9124 4354 9125 4347 9122 4345 9123
      4344 9122 4338 9121 4332 9160
TIME...MOT...LOC 2125Z 267DEG 26KT 4361 9141 4350 9126
          4337 9124

$$

IAC005-MNC055-182200-
/O.CON.KARX.SV.W.0071.000000T0000Z-120718T2200Z/
ALLAMAKEE IA-HOUSTON MN-
428 PM CDT WED JUL 18 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR SOUTHEASTERN
HOUSTON AND NORTHERN ALLAMAKEE COUNTIES UNTIL 500 PM CDT...

LOCAL LAW ENFORCEMENT OFFICIALS REPORTED WIND DAMAGE ACROSS PARTS OF 
ALLAMAKEE COUNTY.

AT 424 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
THUNDERSTORMS WERE ROUGHLY ALONG A LINE EXTENDING FROM CALEDONIA TO
NEW ALBIN TO LANSING...MOVING EAST AT 30 MPH. THESE STORMS CAN
PRODUCE DAMAGING WINDS IN EXCESS OF 60 MPH.

* THE SEVERE THUNDERSTORMS WILL BE NEAR...
  BROWNSVILLE AROUND 440 PM...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

SEVERE THUNDERSTORMS POSE A SIGNIFICANT DANGER TO BOATERS. IF ON AREA
RIVERS...IMMEDIATELY MOVE TO SHORE AND FIND SHELTER.
ESTERN WISCONSIN.

&&

LAT...LON 4350 9161 4357 9158 4375 9126 4361 9127
      4359 9124 4354 9125 4347 9122 4345 9123
      4344 9122 4338 9121 4332 9160
TIME...MOT...LOC 2125Z 267DEG 26KT 4361 9141 4350 9126
          4337 9124
WIND...HAIL 60MPH <.50IN

$$

SHEA

752 
WWUS53 KARX 182136
SVSARX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
436 PM CDT WED JUL 18 2012

IAC005-MNC055-182145-
/O.CAN.KARX.SV.W.0071.000000T0000Z-120718T2200Z/
ALLAMAKEE IA-HOUSTON MN-
436 PM CDT WED JUL 18 2012

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN HOUSTON AND
NORTHERN ALLAMAKEE COUNTIES IS CANCELLED...

THE DAMAGING WIND FROM EARLIER STORMS HAS MOVED OUT OF THE WARNED 
AREA. STORMS WILL LINGER IN THE AREA WITH HEAVY RAIN AND LIGHTNING 
BUT THE STRONGEST OF THE WIND HAS SHIFTED EAST.

LAT...LON 4350 9161 4357 9158 4375 9126 4361 9127
      4359 9124 4354 9125 4347 9122 4345 9123
      4344 9122 4338 9121 4332 9160
TIME...MOT...LOC 2135Z 267DEG 26KT 4361 9131 4350 9116
          4337 9114

$$

SHEA

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 18, 3:19 PM CDT	Severe Thunderstorm Warning	ARX	Winneshiek	41 min
Jul 18, 3:22 PM CDT	Severe Thunderstorm Warning	ARX	Chickasaw	38 min
Jul 18, 12:40 PM CDT	Severe Thunderstorm Warning	ARX	Dodge, Mower	50 min
Jul 18, 1:29 PM CDT	Severe Thunderstorm Warning	ARX	Mower	61 min
Jul 18, 2:24 PM CDT	Severe Thunderstorm Warning	ARX	Fillmore	51 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2012 Severe Thunderstorm Warnings in Minnesota, 2012 Every 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.