Alert archive / Iowa / Tornado Warnings in 2009

Tornado Warning 28, NWS La Crosse, WI

August 19, 2009Allamakee County, Iowa

NWS La Crosse, WI issued this tornado warning at Aug 19, 2009, 5:20 PM CDT for Allamakee County, Iowa. It was in force for 31 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, 5:20 PM CDT (22:20 UTC)
Expired
Aug 19, 2009, 5:51 PM CDT
In force
31 min
Issued by
NWS La Crosse, WI
Area
Storm-based polygon

County Allamakee County, IA

The radar

The La Crosse radar (KARX), 53 km from the middle of the area, began a volume at 22:20 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
Aug 19, 4:49 PM CDTTornado WatchSPC5 hr

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 10.3 hours before the alert went out and 202 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 192220
TORARX
IAC005-192315-
/O.NEW.KARX.TO.W.0028.090819T2220Z-090819T2315Z/

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

THE NATIONAL WEATHER SERVICE IN LA CROSSE HAS ISSUED A

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

* UNTIL 615 PM CDT

* AT 517 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  THUNDERSTORM WITH A POSSIBLE TORNADO 5 MILES SOUTH OF              
  WAUKON...MOVING NORTHEAST AT 20 MPH. THIS STORM PRODUCED A TORNADO 
  NEAR WEST UNION AND CONTINUES TO SHOW THE POTENTIAL FOR ANOTHER    
  TORNADO. 

* THE TORNADO WILL BE NEAR...
  MAUD AROUND 525 PM...
  ELON AND DALBY AROUND 540 PM...
  CHURCHTOWN AROUND 545 PM...
  LANSING AND RED BARN CAMPGROUND AROUND 600 PM...


THIS REPLACES THE PREVIOUS TORNADO WARNING FOR ALLAMAKEE COUNTY. THE 
STORM IS INTENSIFYING. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

&&

LAT...LON 4322 9152 4351 9126 4350 9123 4345 9124
      4342 9120 4338 9121 4335 9117 4332 9109
      4331 9108 4317 9145
TIME...MOT...LOC 2218Z 227DEG 19KT 4321 9145

$$

BAUMGARDT
1 follow-up statement
000 
WWUS53 KARX 192251
SVSARX

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

IAC005-192258-
/O.CAN.KARX.TO.W.0028.000000T0000Z-090819T2315Z/
ALLAMAKEE IA-
551 PM CDT WED AUG 19 2009

...THE TORNADO WARNING FOR ALLAMAKEE COUNTY IS CANCELLED...

THE STORM WHICH PROMPTED THIS WARNING NO LONGER APPEARS CAPABLE OF 
PRODUCING A TORNADO. HEAVY RAIN IS FALLING IN ALLAMAKEE COUNTY FROM 
SOUTHWEST TO NORTHEAST. IT IS LIKELY THAT 1 TO 2 INCHES OF RAIN HAS 
FALLEN THERE. 

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

LAT...LON 4322 9152 4351 9126 4350 9123 4345 9124
      4342 9120 4338 9121 4335 9117 4332 9109
      4331 9108 4317 9145
TIME...MOT...LOC 2248Z 227DEG 19KT 4332 9129

$$

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, 4:26 PM CDTTornado WarningARXAllamakee49 min
Aug 19, 4:38 PM CDTTornado WarningARXClayton, Fayette52 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.