Alert archive / Iowa / Tornado Warnings in 2004

Tornado Warning 3, NWS La Crosse, WI

April 17, 2004Floyd County, Iowa

NWS La Crosse, WI issued this tornado warning at Apr 17, 2004, 10:47 PM CDT for Floyd County, Iowa. It was in force for 73 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 17, 2004, 10:47 PM CDT (03:47 UTC)
Expired
Apr 18, 2004, 12:00 AM CDT
In force
73 min
Issued by
NWS La Crosse, WI
Area
Counties, with a storm outline in the text

County Floyd County, IA

The radar

The La Crosse radar (KARX), 154 km from the middle of the area, began a volume at 03:50 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 17, 7:45 PM CDTSevere Thunderstorm WatchSPC5 hr
Apr 17, 10:05 PM CDTTornado WatchSPC5 hr

The nearest sounding before it

Minneapolis, MN (KMPX), launched 00:00Z, 3.8 hours before the alert went out and 204 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 2004-04-18Temperature 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 2004-04-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 91 square meters per square second.1939587897117Sfc1 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
2026 m above ground
0-6 km bulk shear
65 kt
0-1 km storm-relative helicity
91 m²/s²
0-3 km storm-relative helicity
489 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

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

736 
WFUS53 KARX 180347
TORARX
IAC067-180500-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE LA CROSSE WI
1045 PM CDT SAT APR 17 2004

THE NATIONAL WEATHER SERVICE IN LA CROSSE HAS ISSUED A

* TORNADO WARNING FOR...
  FLOYD COUNTY IN NORTH CENTRAL IOWA

* UNTIL 1200 AM CDT OR MIDNIGHT

* AT 1044 PM CDT...LARGE HAIL WAS FALLING AT FLOYD IN FLOYD COUNTY.
  A THUNDERSTORM WITH POSSIBLE TORNADO WAS IN EASTERN FLOYD COUNTY...
  JUST EAST OF CHARLES CITY. AND...ANOTHER SEVERE THUNDERSTORM IS
  MOVING TOWARD NORTHWEST FLOYD COUNTY FROM WORTH COUNTY.

* THE TORNADO WILL BE NEAR...
  RURAL AREAS OF EASTERN FLOYD COUNTY THROUGH 1050 PM...
  NORA SPRINGS AT 1130 PM.

THIS IS AN EXTENSION OF THE EARLIER TORNADO WARNING.

THIS STORM HAS A HISTORY OF PRODUCING A TORNADO TAKE COVER IN A 
BASEMENT OR IN AN INTERIOR ROOM ON THE LOWEST FLOOR AND STAY AWAY 
FROM WINDOWS TRUCKS HAVE BEEN BLOWN OVER ON INTERSTATE 35 AND
THE NEXT STORM IS TRACKING TOWARD NORTHWEST FLOYD COUNTY.

LAT...LON 4320 9300 4295 9300 4295 9257 4322 9257

$$

SHEA

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 17, 9:41 PM CDTTornado WarningARXFloyd64 min
Apr 17, 9:44 PM CDTSevere Thunderstorm WarningARXMitchell61 min
Apr 17, 9:58 PM CDTSevere Thunderstorm WarningARXAllamakee47 min
Apr 17, 10:36 PM CDTTornado WarningARXChickasaw69 min
Apr 17, 10:49 PM CDTTornado WarningARXMitchell56 min
Apr 17, 10:52 PM CDTSevere Thunderstorm WarningARXAllamakee23 min
Apr 17, 11:24 PM CDTSevere Thunderstorm WarningARXHoward96 min
Apr 17, 11:37 PM CDTSevere Thunderstorm WarningARXWinneshiek83 min

Nearby

Tornado Warnings in Iowa, 2004Every tornado warning in 2004Tornadoes in 2004

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.