Alert archive / Iowa / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 45, NWS La Crosse, WI

June 21, 2011Floyd County, Iowa

NWS La Crosse, WI issued this severe thunderstorm warning at Jun 21, 2011, 1:05 AM CDT for Floyd County, Iowa. It was in force for 40 min. 3 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
Jun 21, 2011, 1:05 AM CDT (06:05 UTC)
Expired
Jun 21, 2011, 1:45 AM CDT
In force
40 min
Issued by
NWS La Crosse, WI
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

County Floyd County, IA

The radar

The La Crosse radar (KARX), 158 km from the middle of the area, began a volume at 06:05 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
Jun 21, 1:20 AM CDTTSTM WND GST 60Charles City, IA
Jun 21, 1:25 AM CDTTSTM WND GST 50Charles City, IA
Jun 21, 1:30 AM CDTTSTM WND DMGCharles City, IAA NUMBER OF 1 TO 3 FOOT DIAMETER TREES DOWN ACROSS THE CITY.

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

The nearest sounding before it

Minneapolis, MN (KMPX), launched 00:00Z, 6.1 hours before the alert went out and 208 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 2011-06-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 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, Minneapolis, MN at 00:00Z on 2011-06-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -2 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
979 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
-2 m²/s²
0-3 km storm-relative helicity
104 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.

153 
WUUS53 KARX 210605
SVRARX
IAC067-210645-
/O.NEW.KARX.SV.W.0045.110621T0605Z-110621T0645Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE LA CROSSE WI
105 AM CDT TUE JUN 21 2011

THE NATIONAL WEATHER SERVICE IN LA CROSSE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  FLOYD COUNTY IN NORTH CENTRAL IOWA...

* UNTIL 145 AM CDT

* AT 101 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM LOCATED NEAR MARBLE ROCK...OR 15 MILES
  SOUTHWEST OF CHARLES CITY...MOVING NORTHEAST AT 45 MPH. THIS STORM
  CAN PRODUCE PENNY SIZE HAIL AND DAMAGING WINDS IN EXCESS OF 60 MPH.
   

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  ROCKFORD AROUND 110 AM...  
  OAKWOOD 115 AM...  
  CHARLES CITY AND RUDD AROUND 120 AM...
  FLOYD AND IDLEWILDE STATE PARK AROUND 125 AM...
  HOWARDVILLE AND COLWELL COUNTY PARK AROUND 130 AM...

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.

&&

LAT...LON 4321 9292 4321 9256 4291 9256 4290 9302
      4291 9303
TIME...MOT...LOC 0604Z 210DEG 38KT 4294 9287
WIND...HAIL 60MPH 0.75IN

$$

04
3 follow-up statements
403 
WWUS53 KARX 210621
SVSARX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
121 AM CDT TUE JUN 21 2011

IAC067-210645-
/O.CON.KARX.SV.W.0045.000000T0000Z-110621T0645Z/
FLOYD IA-
121 AM CDT TUE JUN 21 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR FLOYD COUNTY
UNTIL 145 AM CDT...

AT 119 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM LOCATED NEAR FLOYD CROSSING...OR NEAR CHARLES
CITY...MOVING NORTHEAST AT 45 MPH. THIS STORM CAN PRODUCE QUARTER
SIZE HAIL AND DAMAGING WINDS IN EXCESS OF 60 MPH.

A SECOND SEVERE THUNDERSTORM WAS JUST MOVING INTO THE SOUTHERN PART 
OF THE COUNTY SOUTHEAST OF MARBLE ROCK. THIS STORM IS ALSO CAPABLE 
OF PRODUCING DAMAGING WINDS IN EXCESS OF 60 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  FLOYD AND IDLEWILDE STATE PARK AROUND 125 AM...
  HOWARDVILLE AND COLWELL COUNTY PARK AROUND 130 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 4290 9297 4321 9292 4321 9256 4291 9256
TIME...MOT...LOC 0620Z 210DEG 38KT 4309 9275
WIND...HAIL 60MPH 1.00IN

$$

04
006 
WWUS53 KARX 210633
SVSARX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
133 AM CDT TUE JUN 21 2011

IAC067-210645-
/O.CON.KARX.SV.W.0045.000000T0000Z-110621T0645Z/
FLOYD IA-
133 AM CDT TUE JUN 21 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR EASTERN FLOYD
COUNTY UNTIL 145 AM CDT...

BROADCAST MEDIA REPORTED WINDS OF 60 MPH IN CHARLES CITY AT 120 AM 
CDT WITH A SEVERE THUNDERSTORM. 

AT 129 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM LOCATED NEAR HOWARDVILLE...OR 7 MILES NORTH OF
CHARLES CITY...MOVING NORTHEAST AT 45 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 4302 9282 4321 9292 4321 9256 4291 9256
TIME...MOT...LOC 0632Z 210DEG 38KT 4320 9266
WIND...HAIL 60MPH 1.00IN

$$

04
498 
WWUS53 KARX 210641
SVSARX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
141 AM CDT TUE JUN 21 2011

IAC067-210651-
/O.EXP.KARX.SV.W.0045.000000T0000Z-110621T0645Z/
FLOYD IA-
141 AM CDT TUE JUN 21 2011

...THE SEVERE THUNDERSTORM WARNING FOR EASTERN FLOYD COUNTY WILL
EXPIRE AT 145 AM CDT...

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

LAT...LON 4302 9282 4321 9292 4321 9256 4291 9256
TIME...MOT...LOC 0641Z 210DEG 38KT 4328 9259

$$

04

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 21, 1:29 AM CDTSevere Thunderstorm WarningARXChickasaw, Howard, Mitchell47 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2011Every severe thunderstorm warning 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.