Alert archive / Iowa / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 102, NWS La Crosse, WI

July 8, 1997Fayette County, Winneshiek County, Iowa

NWS La Crosse, WI issued this severe thunderstorm warning at Jul 8, 1997, 1:36 AM CDT for Fayette County, Winneshiek County, Iowa. It was in force for 34 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 8, 1997, 1:36 AM CDT (06:36 UTC)
Expired: Jul 8, 1997, 2:10 AM CDT
In force: 34 min
Issued by: NWS La Crosse, WI
Area: Whole counties

Counties Fayette County, IA, Winneshiek County, IA

The radar

The La Crosse radar (KARX), 98 km from the middle of the area, began a volume at 06:40 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.

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 6.6 hours before the alert went out and 196 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 17 J/kg
Mixed-layer CIN: -110 J/kg
Mixed-layer LCL: 1553 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 26 m²/s²
0-3 km storm-relative helicity: 94 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 
TTAA00 KLSE 080637 RRA
SVRLSE
IAC065-191-080710-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING...CORRECTED
NATIONAL WEATHER SERVICE LA CROSSE WI
136 AM CDT TUE JUL 8 1997

* SEVERE THUNDERSTORM WARNING FOR
    SOUTHERN WINNESHIEK COUNTY - NORTHEASTERN IOWA
    NORTHERN FAYETTE COUNTY - NORTHEASTERN IOWA

* UNTIL 210 AM CDT
 
* SOME LOCATIONS AFFECTED
    SPILLVILLE
    CALMAR
    FESTINA

* AT 130 AM NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED SEVERE
  THUNDERSTORMS 15 MILES SOUTHWEST OF DECORAH...JUST WEST OF
  SPILLVILLE AND 15 MILES SOUTH OF DECORAH NEAR FESTINA. THESE
  STORMS WERE MOVING EAST AT 35 MPH.

* THESE STORMS WILL BE NEAR CALMAR BY 145 AM.

THESE STORMS WILL CONTAIN LARGE HAIL AND DAMAGING WIND. DO NOT GO
OUTDOORS.


NELSON

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS La Crosse, WI wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 7, 2:22 PM CDT, 11 hours 14 minutes earlier.

Area forecast discussion, Jul 7, 2:22 PM CDT, 11 hours 14 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
222 PM CDT MON JUL 7 1997

TONIGHTS FORECAST PROBLEM WILL BE THUNDERSTORMS CHANCES.

REGIONAL 88DS CONTINUED TO SHOW REMNANTS OF LAST NIGHTS DAKS MCS
CONTINUING TO THRIVE ON WARM ADVECTION AND MOISTURE TRANSPORT AS IT
MOVED ACROSS MN. THE SOUTHEAST PORTION WAS BEING AFFECTED BY RELATIVELY
DRY ATMOSPHERE OVER SE MN/NE IA. MORE THUNDERSTORMS WERE TRYING TO FORM
VCNTY OF KFSD.

MESOANALYSIS HAD A WARM FRONT FROM CENTRAL NEBR TO SW IA...WITH MID TO
UPPER 60S DEW POINTS POOLING JUST SOUTH OF THERE. IN OUR FORECAST
AREA...DEW POINTS WERE STILL IN THE 40S TO NEAR 50.

12Z MODELS IN BASIC AGREEMENT ON WEATHER PATTERNS TONIGHT. THE WARM
FRONT MOVES NORTH INTO NRN IA...BUT PROBABLY NOT AS FAR AS MODELS HAVE
IT DUE TO ANTICIPATED CONVECTION. A 40 KNOT LOW LEVEL JET IMPINGING ON
THIS WARM FRONT AND TREMENDOUS WARM ADVECTION BULLSYED OVER FORECAST
AREA...WILL BRING HIGH CHANCES OF RAIN.  BEST MOISTURE TRANSPORT AND
WARM ADVECTION OCCURS FROM MSP-AUW SO EXPECT THE BEST OVERRUNNING RAINS
THERE. ETA QPF SEEMS A BIT FAR NORTH WITH THESE RAINS.

MEANWHILE...BEST INSTABILITY WILL REMAIN OVER IA SOUTH OF THE WARM
FRONT. SEVERE STORMS ARE A GOOD BET OVER NW IA INTO ERN NEBR THIS
EVENING...EVOLVING INTO A MESOSCALE CONVECTIVE COMPLEX OVER MUCH OF IA
OVERNIGHT. IN FACT...CUMULUS FIELD ALREADY EVIDENT OVER NC NEBR INTO SE
SD...ITS ONLY A MATTER OF TIME BEFORE THAT AREA SEES THUNDERSTORMS.
CORFIDI VECTORS AND THICKNESSES SUGGEST AN ESE MOVEMENT...PROBABLY
TAKING THE LIONS SHARE OF RAIN JUST SOUTH OF NE IA.

IN BETWEEN...ETA FORECASTING SUBSTANTIAL CONVERGENCE ALONG TROUGH
AXIS...SO WE SHOULD GENERATE ENOUGH LIFT TO BRING HIGH POPS TO CENTRAL
PORTIONS OF THE FORECAST AREA TOO.

SO IN SUMMARY...ITS GOING TO RAIN...WITH BEST CHANCES IN THE NORTHERN
AND SOUTHERN TIERS OF COUNTIES.  FWC MINS LOOK GOOD.

THANKS TO DMX FOR THE COORDINATION CALL.

RACY

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 8, 1:00 AM CDT	Severe Thunderstorm Warning	ARX	Fayette, Winneshiek	30 min

Nearby

Severe Thunderstorm Warnings in Iowa, 1997 Every severe thunderstorm warning 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.