Alert archive / Iowa / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 4, NWS La Crosse, WI

May 2, 2012Allamakee County, Clayton County, Iowa

NWS La Crosse, WI issued this severe thunderstorm warning at May 2, 2012, 1:26 AM CDT for Allamakee County, Clayton County, Iowa. It was in force for 30 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: May 2, 2012, 1:26 AM CDT (06:26 UTC)
Expired: May 2, 2012, 1:56 AM CDT
In force: 30 min
Issued by: NWS La Crosse, WI
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Allamakee County, IA, Clayton County, IA

The radar

The La Crosse radar (KARX), 86 km from the middle of the area, began a volume at 06:26 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
May 2, 1:36 AM CDT	HAIL 1	2 Sw Volney, IA

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 00:00Z, 6.4 hours before the alert went out and 183 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 572 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: 26 m²/s²
0-3 km storm-relative helicity: 117 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.

470 
WUUS53 KARX 020626
SVRARX
IAC005-043-020700-
/O.NEW.KARX.SV.W.0004.120502T0626Z-120502T0700Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE LA CROSSE WI
126 AM CDT WED MAY 2 2012

THE NATIONAL WEATHER SERVICE IN LA CROSSE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHWESTERN ALLAMAKEE COUNTY IN NORTHEAST IOWA...
  NORTHWESTERN CLAYTON COUNTY IN NORTHEAST IOWA...

* UNTIL 200 AM CDT

* AT 121 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM LOCATED NEAR COUNTY ROADS B 56 AND W 64...OR 13
  MILES NORTHWEST OF ELKADER...MOVING NORTHEAST AT 35 MPH. THIS STORM
  CAN PRODUCE QUARTER SIZE HAIL AND DAMAGING WINDS IN EXCESS OF 60
  MPH.  

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  HARDIN AROUND 130 AM...
  COUNTY ROADS X 16 AND B 38 AROUND 135 AM...
  VOLNEY AROUND 140 AM...  
  ROSSVILLE AND STATE ROAD 76 AND COUNTY X 16 AROUND 145 AM...       
  WAUKON AND MAUD AROUND 150 AM...

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 4298 9161 4309 9160 4329 9146 4322 9126
      4295 9150
TIME...MOT...LOC 0625Z 209DEG 31KT 4305 9152
WIND...HAIL 60MPH 1.00IN

$$

ZT

3 follow-up statements

471 
WWUS53 KARX 020640
SVSARX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
140 AM CDT WED MAY 2 2012

IAC005-043-020700-
/O.CON.KARX.SV.W.0004.000000T0000Z-120502T0700Z/
ALLAMAKEE IA-CLAYTON IA-
140 AM CDT WED MAY 2 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR NORTH CENTRAL
CLAYTON AND SOUTH CENTRAL ALLAMAKEE COUNTIES UNTIL 200 AM CDT...

AT 135 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM LOCATED NEAR LUANA...OR 13 MILES SOUTH OF
WAUKON...MOVING NORTHEAST AT 35 MPH. THIS STORM CAN PRODUCE QUARTER
SIZE HAIL AND DAMAGING WINDS IN EXCESS OF 60 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  VOLNEY AROUND 145 AM...
  ROSSVILLE AND STATE ROAD 76 AND COUNTY X 16 AROUND 150 AM...
  WAUKON AND WATERVILLE AROUND 155 AM...

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 4302 9144 4305 9154 4311 9158 4329 9146
      4322 9126
TIME...MOT...LOC 0640Z 213DEG 29KT 4312 9143
WIND...HAIL 60MPH 1.00IN

$$

ZT

231 
WWUS53 KARX 020649
SVSARX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
149 AM CDT WED MAY 2 2012

IAC043-020659-
/O.CAN.KARX.SV.W.0004.000000T0000Z-120502T0700Z/
CLAYTON IA-
149 AM CDT WED MAY 2 2012

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN CLAYTON COUNTY IS
CANCELLED...

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

LAT...LON 4322 9126 4309 9138 4311 9143 4320 9152
      4329 9146
TIME...MOT...LOC 0649Z 211DEG 30KT 4319 9132

$$

IAC005-020700-
/O.CON.KARX.SV.W.0004.000000T0000Z-120502T0700Z/
ALLAMAKEE IA-
149 AM CDT WED MAY 2 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR CENTRAL
ALLAMAKEE COUNTY UNTIL 200 AM CDT...

AT 145 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM LOCATED NEAR ROSSVILLE...OR 10 MILES SOUTHEAST OF
WAUKON...MOVING NORTHEAST AT 35 MPH. THIS STORM CAN PRODUCE QUARTER
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 LARGE
HAIL AND DAMAGING WINDS. SEEK SHELTER NOW INSIDE A STURDY STRUCTURE
AND STAY AWAY FROM WINDOWS.

&&

LAT...LON 4322 9126 4309 9138 4311 9143 4320 9152
      4329 9146
TIME...MOT...LOC 0649Z 211DEG 30KT 4319 9132
WIND...HAIL 60MPH 1.00IN

$$

ZT

652 
WWUS53 KARX 020656
SVSARX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
156 AM CDT WED MAY 2 2012

IAC005-020706-
/O.CAN.KARX.SV.W.0004.000000T0000Z-120502T0700Z/
ALLAMAKEE IA-
156 AM CDT WED MAY 2 2012

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL ALLAMAKEE COUNTY IS
CANCELLED...

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

LAT...LON 4322 9126 4309 9138 4311 9143 4320 9152
      4329 9146
TIME...MOT...LOC 0656Z 213DEG 29KT 4323 9133

$$

ZT

The office that day

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

Issued	Product	Office	Counties	Lasted
May 2, 3:47 PM CDT	Flash Flood Watch	ARX	Chickasaw, Clayton, Fayette, Floyd	12 hr

Nearby

Severe Thunderstorm Warnings in Iowa, 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.