Alert archive / Iowa / Tornado Warnings in 1997

Tornado Warning 9, NWS La Crosse, WI

July 1, 1997Clayton County, Iowa

NWS La Crosse, WI issued this tornado warning at Jul 1, 1997, 11:25 PM CDT for Clayton County, Iowa. It was in force for 45 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Jul 1, 1997, 11:25 PM CDT (04:25 UTC)
Expired
Jul 2, 1997, 12:10 AM CDT
In force
45 min
Issued by
NWS La Crosse, WI
Area
Whole counties

County Clayton County, IA

The radar

The La Crosse radar (KARX), 109 km from the middle of the area, began a volume at 04:25 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
Jul 1, 8:45 PM CDTTornado WatchSPC5 hr

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 4.4 hours before the alert went out and 153 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 00:00Z on 1997-07-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1089 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Davenport, at 00:00Z on 1997-07-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 40 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
1089 J/kg
Mixed-layer CIN
-144 J/kg
Mixed-layer LCL
1458 m above ground
0-6 km bulk shear
51 kt
0-1 km storm-relative helicity
40 m²/s²
0-3 km storm-relative helicity
236 m²/s²
Significant tornado parameter
0.1
Supercell composite
1.4

Open this sounding in Storm Lab

The text

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

008 
WFUS1 KLSE 020426 RRA
TORLSE
IAC043-020510-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE LA CROSSE WI
1125 PM CDT TUE JUL 1 1997

* TORNADO WARNING FOR
    EASTERN CLAYTON COUNTY - NORTHEASTERN IOWA

* UNTIL 1210 AM CDT
 
* SOME LOCATIONS AFFECTED
    FARMERSBURG
    MC GREGOR
    CLAYTON
    GARNAVILLO

* AT 1123 PM NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  TORNADO NEAR FARMERSBURG OR 31 MILES SOUTHEAST OF DECORAH. THE
  STORM WAS MOVING EAST AT 20 MPH.

* THE STORM WILL BE NEAR GARNAVILLO BY 1130 PM.

IF YOU ARE NEAR THIS DANGEROUS STORM...TAKE COVER IMMEDIATELY IN
THE LOWEST FLOOR AND INNER MOST ROOM OF A BUILDING.

KING

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 1, 8:56 PM CDTSevere Thunderstorm WarningARXWinneshiek64 min
Jul 1, 9:24 PM CDTTornado WarningARXAllamakee, Winneshiek31 min
Jul 1, 9:53 PM CDTTornado WarningARXAllamakee37 min
Jul 1, 10:29 PM CDTTornado WarningARXAllamakee31 min
Jul 1, 11:03 PM CDTSevere Thunderstorm WarningARXClayton57 min

Nearby

Tornado Warnings in Iowa, 1997Every tornado warning in 1997Tornadoes in 1997

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.