Alert archive / Iowa / Tornado Warnings in 2011

Tornado Warning 2, NWS La Crosse, WI

April 9, 20114 counties in Iowa

NWS La Crosse, WI issued this tornado warning at Apr 9, 2011, 10:53 PM CDT for 4 counties in Iowa. It was in force for 37 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
Apr 9, 2011, 10:53 PM CDT (03:53 UTC)
Expired
Apr 9, 2011, 11:30 PM CDT
In force
37 min
Issued by
NWS La Crosse, WI
Area
Storm-based polygon

Counties Chickasaw County, IA, Floyd County, IA, Howard County, IA, Mitchell County, IA

The radar

The La Crosse radar (KARX), 130 km from the middle of the area, began a volume at 03:54 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
Apr 9, 7:42 PM CDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Minneapolis, MN (KMPX), launched 00:00Z, 3.9 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, Minneapolis, MN at 00:00Z on 2011-04-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Minneapolis, MN at 00:00Z on 2011-04-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 355 square meters per square second.1939587897Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
612 m above ground
0-6 km bulk shear
54 kt
0-1 km storm-relative helicity
355 m²/s²
0-3 km storm-relative helicity
550 m²/s²
Significant tornado parameter
0.0
Supercell composite
5.2

Open this sounding in Storm Lab

The text

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

757 
WFUS53 KARX 100353
TORARX
IAC037-067-089-131-100430-
/O.NEW.KARX.TO.W.0002.110410T0353Z-110410T0430Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE LA CROSSE WI
1053 PM CDT SAT APR 9 2011

THE NATIONAL WEATHER SERVICE IN LA CROSSE HAS ISSUED A

* TORNADO WARNING FOR...
  NORTHEASTERN FLOYD COUNTY IN NORTH CENTRAL IOWA...
  SOUTHEASTERN MITCHELL COUNTY IN NORTH CENTRAL IOWA...
  NORTHWESTERN CHICKASAW COUNTY IN NORTHEAST IOWA...
  SOUTHWESTERN HOWARD COUNTY IN NORTHEAST IOWA...

* UNTIL 1130 PM CDT

* AT 1050 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  TORNADO NEAR HOWARDVILLE...OR 8 MILES NORTH OF CHARLES CITY...
  MOVING NORTHEAST AT 35 MPH.

* THE TORNADO WILL BE NEAR...
  COLWELL AND NEW HAVEN AROUND 1100 PM...
  COUNTY ROADS 17 AND T 72 AND DEERFIELD AROUND 1105 PM...
  COUNTY B 17 AND BELL AVENUE AROUND 1110 PM...
  ELMA AND RICEVILLE AROUND 1115 PM...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER IN A BASEMENT OR IN AN INTERIOR ROOM ON THE LOWEST FLOOR
AND STAY AWAY FROM WINDOWS! CARS AND MOBILE HOMES SHOULD BE ABANDONED
FOR A STURDY BUILDING. AS A LAST RESORT...LAY FLAT IN A DITCH AND
COVER YOUR HEAD.

&&

LAT...LON 4341 9251 4315 9234 4306 9276 4323 9286
TIME...MOT...LOC 0353Z 242DEG 29KT 4319 9269

$$

HALBACH
4 follow-up statements
181 
WWUS53 KARX 100402
SVSARX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
1102 PM CDT SAT APR 9 2011

IAC037-067-089-131-100430-
/O.CON.KARX.TO.W.0002.000000T0000Z-110410T0430Z/
MITCHELL IA-HOWARD IA-FLOYD IA-CHICKASAW IA-
1102 PM CDT SAT APR 9 2011

...A TORNADO WARNING REMAINS IN EFFECT FOR NORTHWESTERN CHICKASAW...
NORTHEASTERN FLOYD...SOUTHWESTERN HOWARD AND SOUTHEASTERN MITCHELL
COUNTIES UNTIL 1130 PM CDT...

AT 1059 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
TORNADO LOCATED NEAR COLWELL COUNTY PARK...OR 8 MILES NORTH OF
CHARLES CITY...MOVING NORTHEAST AT 30 MPH. IN ADDITION TO A
TORNADO...THIS STORM CAN PRODUCE QUARTER SIZE HAIL AND DAMAGING WINDS
IN EXCESS OF 60 MPH.

* THE TORNADO WILL BE NEAR...
  COUNTY ROADS 17 AND T 72 AROUND 1110 PM...
  COUNTY B 17 AND BELL AVENUE AND DEERFIELD AROUND 1115 PM...
  RICEVILLE AND COUNTY ROADS B 28 AND V 18 AROUND 1120 PM...
  ELMA AND LYLAHS MARSH COUNTY PARK AROUND 1125 PM...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER IN A BASEMENT OR IN AN INTERIOR ROOM ON THE LOWEST FLOOR
AND STAY AWAY FROM WINDOWS! CARS AND MOBILE HOMES SHOULD BE ABANDONED
FOR A STURDY BUILDING. AS A LAST RESORT...LAY FLAT IN A DITCH AND
COVER YOUR HEAD.

A TORNADO WATCH REMAINS IN EFFECT UNTIL 500 AM SUNDAY MORNING FOR
NORTHEASTERN IOWA AND SOUTHEAST MINNESOTA AND SOUTHWESTERN WISCONSIN.

&&

LAT...LON 4341 9251 4315 9234 4306 9276 4323 9286
TIME...MOT...LOC 0403Z 246DEG 24KT 4319 9263

$$

HALBACH
491 
WWUS53 KARX 100412
SVSARX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
1112 PM CDT SAT APR 9 2011

IAC037-067-089-131-100430-
/O.CON.KARX.TO.W.0002.000000T0000Z-110410T0430Z/
MITCHELL IA-HOWARD IA-FLOYD IA-CHICKASAW IA-
1112 PM CDT SAT APR 9 2011

...A TORNADO WARNING REMAINS IN EFFECT FOR NORTHWESTERN CHICKASAW...
NORTHEASTERN FLOYD...SOUTHWESTERN HOWARD AND SOUTHEASTERN MITCHELL
COUNTIES UNTIL 1130 PM CDT...

AT 1108 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
TORNADO LOCATED NEAR COUNTY ROADS 17 AND T 72...OR 11 MILES NORTH OF
CHARLES CITY...MOVING NORTHEAST AT 30 MPH. IN ADDITION TO A
TORNADO...THIS STORM CAN PRODUCE QUARTER SIZE HAIL AND DAMAGING WINDS
IN EXCESS OF 60 MPH.

* THE TORNADO WILL BE NEAR...
  RICEVILLE AND COUNTY ROADS B 28 AND V 18 AROUND 1120 PM...
  ELMA AND LYLAHS MARSH COUNTY PARK AROUND 1125 PM...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER IN A BASEMENT OR IN AN INTERIOR ROOM ON THE LOWEST FLOOR
AND STAY AWAY FROM WINDOWS! CARS AND MOBILE HOMES SHOULD BE ABANDONED
FOR A STURDY BUILDING. AS A LAST RESORT...LAY FLAT IN A DITCH AND
COVER YOUR HEAD.

A TORNADO WATCH REMAINS IN EFFECT UNTIL 500 AM SUNDAY MORNING FOR
NORTHEASTERN IOWA AND SOUTHEAST MINNESOTA AND SOUTHWESTERN WISCONSIN.

&&

LAT...LON 4331 9271 4341 9251 4315 9234 4309 9262
TIME...MOT...LOC 0413Z 246DEG 24KT 4324 9256

$$

HALBACH
020 
WWUS53 KARX 100421
SVSARX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
1121 PM CDT SAT APR 9 2011

IAC067-131-100431-
/O.CAN.KARX.TO.W.0002.000000T0000Z-110410T0430Z/
MITCHELL IA-FLOYD IA-
1121 PM CDT SAT APR 9 2011

...THE TORNADO WARNING FOR NORTHEASTERN FLOYD AND SOUTHEASTERN
MITCHELL COUNTIES IS CANCELLED...

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

A TORNADO WATCH REMAINS IN EFFECT UNTIL 500 AM CDT SUNDAY MORNING FOR
NORTHEASTERN IOWA AND SOUTHEAST MINNESOTA AND SOUTHWESTERN WISCONSIN.
A SEVERE THUNDERSTORM WATCH ALSO REMAINS IN EFFECT UNTIL 300 AM CDT
SUNDAY MORNING FOR SOUTHEAST MINNESOTA AND WEST CENTRAL WISCONSIN.

LAT...LON 4312 9251 4337 9256 4341 9251 4315 9234
TIME...MOT...LOC 0421Z 248DEG 36KT 4327 9242

$$

IAC037-089-100430-
/O.CON.KARX.TO.W.0002.000000T0000Z-110410T0430Z/
HOWARD IA-CHICKASAW IA-
1121 PM CDT SAT APR 9 2011

...A TORNADO WARNING REMAINS IN EFFECT FOR NORTHWESTERN CHICKASAW AND
SOUTHWESTERN HOWARD COUNTIES UNTIL 1130 PM CDT...

AT 1117 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
TORNADO LOCATED NEAR ELMA...OR 15 MILES NORTHWEST OF NEW HAMPTON...
MOVING EAST AT 40 MPH. IN ADDITION TO A TORNADO...THIS STORM CAN
PRODUCE QUARTER SIZE HAIL AND DAMAGING WINDS IN EXCESS OF 60 MPH.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER IN A BASEMENT OR IN AN INTERIOR ROOM ON THE LOWEST FLOOR
AND STAY AWAY FROM WINDOWS! CARS AND MOBILE HOMES SHOULD BE ABANDONED
FOR A STURDY BUILDING. AS A LAST RESORT...LAY FLAT IN A DITCH AND
COVER YOUR HEAD.

A TORNADO WATCH REMAINS IN EFFECT UNTIL 500 AM SUNDAY MORNING FOR
NORTHEASTERN IOWA AND SOUTHEAST MINNESOTA AND SOUTHWESTERN WISCONSIN.

&&

LAT...LON 4312 9251 4337 9256 4341 9251 4315 9234
TIME...MOT...LOC 0421Z 248DEG 36KT 4327 9242

$$

HALBACH
322 
WWUS53 KARX 100425
SVSARX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
1125 PM CDT SAT APR 9 2011

IAC037-089-100436-
/O.EXP.KARX.TO.W.0002.000000T0000Z-110410T0430Z/
HOWARD IA-CHICKASAW IA-
1125 PM CDT SAT APR 9 2011

...THE TORNADO WARNING FOR NORTHWESTERN CHICKASAW AND SOUTHWESTERN
HOWARD COUNTIES WILL EXPIRE AT 1130 PM CDT...

THE TORNADO THREAT HAS DIMINISHED...THEREFORE THE TORNADO WARNING HAS
EXPIRED. HOWEVER...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT
FOR THE AREA.

A TORNADO WATCH REMAINS IN EFFECT UNTIL 500 AM CDT SUNDAY MORNING FOR
NORTHEASTERN IOWA AND SOUTHEAST MINNESOTA AND SOUTHWESTERN WISCONSIN.

LAT...LON 4312 9251 4337 9256 4341 9251 4315 9234
TIME...MOT...LOC 0426Z 248DEG 36KT 4329 9235

$$

HALBACH

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 9, 11:08 PM CDTSevere Thunderstorm WarningARXMitchell52 min
Apr 9, 11:15 PM CDTSevere Thunderstorm WarningARXHoward, Winneshiek45 min
Apr 10, 3:39 PM CDTSevere Thunderstorm WarningARXHoward41 min
Apr 10, 4:11 PM CDTSevere Thunderstorm WarningARXWinneshiek34 min
Apr 10, 5:03 PM CDTSevere Thunderstorm WarningARXAllamakee27 min

Nearby

Tornado Warnings in Iowa, 2011Every tornado warning in 2011Tornadoes in 2011

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.