Alert archive / Iowa / Tornado Warnings in 2009

Tornado Warning 25, NWS La Crosse, WI

August 19, 2009Allamakee County, Iowa

NWS La Crosse, WI issued this tornado warning at Aug 19, 2009, 4:26 PM CDT for Allamakee County, Iowa. It was in force for 49 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
Aug 19, 2009, 4:26 PM CDT (21:26 UTC)
Expired
Aug 19, 2009, 5:15 PM CDT
In force
49 min
Issued by
NWS La Crosse, WI
Area
Storm-based polygon

County Allamakee County, IA

The radar

The La Crosse radar (KARX), 59 km from the middle of the area, began a volume at 21:30 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 nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 9.4 hours before the alert went out and 210 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 2009-08-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 74 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 2009-08-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 126 square meters per square second.19395878Sfc1 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
74 J/kg
Mixed-layer CIN
-55 J/kg
Mixed-layer LCL
943 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
126 m²/s²
0-3 km storm-relative helicity
141 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.

000 
WFUS53 KARX 192126
TORARX
IAC005-192215-
/O.NEW.KARX.TO.W.0025.090819T2126Z-090819T2215Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE LA CROSSE WI
426 PM CDT WED AUG 19 2009

THE NATIONAL WEATHER SERVICE IN LA CROSSE HAS ISSUED A

* TORNADO WARNING FOR...
  WESTERN ALLAMAKEE COUNTY IN NORTHEAST IOWA...

* UNTIL 515 PM CDT

* AT 422 PM CDT...DOPPLER RADAR AND STORM SPOTTERS INDICATED A
  TORNADO 7 MILES NORTHWEST OF LUDLOW...OR 6 MILES EAST OF DECORAH...
  MOVING NORTHEAST AT 25 MPH. THIS STORM HAS A HISTORY OF A TORNADO.

* THE TORNADO WILL BE NEAR...
  COUNTY ROADS A 52 AND W 60 AND COUNTY ROADS X 16 AND W 48 AROUND
  430 PM...
  WAUKON AND HANOVER AROUND 440 PM...
  QUANDAHL AROUND 445 PM...
  DORCHESTER AROUND 455 PM...
  
ANOTHER STORM WITH A TORNADO HISTORY WILL MOVING INTO SOUTHWEST 
ALLAMAKEE COUNTY AFTER 440 PM. THIS STORM WILL ENTER THE COUNTY 
SOUTH OF FRANKSVILLE AND TRACK TOWARD MAUD. THIS STORM PRODUCED A 
TORNADO NEAR WEST UNION IN THE LAST HOUR. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER IN A BASEMENT OR IN AN INTERIOR ROOM ON THE LOWEST FLOOR
AND STAY AWAY FROM WINDOWS

&&

LAT...LON 4346 9162 4350 9161 4350 9135 4309 9136
      4308 9161
TIME...MOT...LOC 2123Z 231DEG 21KT 4331 9167

$$

BAUMGARDT
1 follow-up statement
000 
WWUS53 KARX 192153
SVSARX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
453 PM CDT WED AUG 19 2009

IAC005-192215-
/O.CON.KARX.TO.W.0025.000000T0000Z-090819T2215Z/
ALLAMAKEE IA-
453 PM CDT WED AUG 19 2009

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 515 PM CDT FOR WESTERN
ALLAMAKEE COUNTY...

AT 446 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO 
INDICATE A STORM THAT COULD PRODUCE A TORNADO AT ANY TIME...LOCATED 
NEAR STATE ROAD 51 AND COUNTY W 48...OR 11 MILES SOUTHWEST OF 
WAUKON...MOVING NORTHEAST AT 15 MPH.  

* THE TORNADO WILL BE NEAR...
  LUDLOW AND COUNTY ROADS X 16 AND B 38 AROUND 505 PM...
  WAUKON AND STATE ROAD 76 AND COUNTY X 16 AROUND 515 PM...

FROM DOPPLER RADAR...IT APPEARS THE TORNADO POTENTIAL HAS DIMINISHED 
SOMEWHAT WITH A SECOND STORM LOCATED 2 MILES EAST OF HANOVER. THIS 
STORM ENTERED THE COUNTY NORTH OF GLENWOOD CHURCH.   

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A TORNADO WATCH REMAINS IN EFFECT UNTIL MIDNIGHT THURSDAY MORNING FOR
NORTHEAST IOWA AND SOUTHEAST MINNESOTA AND WESTERN WISCONSIN.

&&

LAT...LON 4346 9162 4350 9161 4350 9135 4309 9136
      4308 9161
TIME...MOT...LOC 2148Z 234DEG 11KT 4315 9159

$$

BAUMGARDT

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 19, 3:33 PM CDTTornado WarningARXFayette42 min
Aug 19, 3:43 PM CDTTornado WarningARXWinneshiek62 min
Aug 19, 4:15 PM CDTTornado WarningARXFayette30 min
Aug 19, 4:38 PM CDTTornado WarningARXClayton, Fayette52 min
Aug 19, 5:20 PM CDTTornado WarningARXAllamakee31 min
Aug 19, 5:59 PM CDTAreal Flood AdvisoryARXAllamakee47 min

Nearby

Tornado Warnings in Iowa, 2009Every tornado warning in 2009Tornadoes in 2009

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.