Alert archive / Iowa / Tornado Warnings in 2004

Tornado Warning 1, NWS La Crosse, WI

April 17, 2004Floyd County, Iowa

NWS La Crosse, WI issued this tornado warning at Apr 17, 2004, 9:41 PM CDT for Floyd County, Iowa. It was in force for 64 min. 2 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
Apr 17, 2004, 9:41 PM CDT (02:41 UTC)
Expired
Apr 17, 2004, 10:45 PM CDT
In force
64 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), 162 km from the middle of the area, began a volume at 02:40 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
Apr 17, 9:54 PM CDTHAIL 1.25Rock Falls, IA
Apr 17, 9:55 PM CDTHAIL 1.25Rock Falls, IA

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

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

The nearest sounding before it

Minneapolis, MN (KMPX), launched 00:00Z, 2.7 hours before the alert went out and 203 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.

956 
WFUS53 KARX 180241
TORARX
IAC067-180345-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE LA CROSSE WI
941 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 1045 PM CDT

* AT 941 PM CDT...NATIONAL WEATHER SERVICE RADAR DETECTED A TORNADO 4
  MILES NORTHWEST OF NORA SPRINGS...OR ABOUT 6 MILES EAST OF MASON
  CITY. THE TORNADO WAS MOVING SOUTHEAST AT 40 MPH.

* THE TORNADO WILL BE NEAR...
  COUNTY ROADS B 20 AND T 26 BY 950 PM CDT...
  RUDD AND ROCKFORD BY 955 PM CDT...
  OAKWOOD AND ROSEVILLE BY 1005 PM CDT...
  HIGHWAY 14 AND COUNTY ROAD B 60 AND CHARLES CITY BY 1010 PM CDT...
  COUNTY ROADS B 60 AND T 64 AND POWERSVILLE BY 1015 PM CDT...

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

LAT...LON 4325 9311 4308 9326 4282 9256 4305 9256

$$

KRC

The office that day

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

IssuedProductOfficeCountiesLasted
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, 10:47 PM CDTTornado WarningARXFloyd73 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.