Severe Thunderstorm Warning 57, NWS La Crosse, WI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
125 PM CDT THU MAY 28 1998

MAIN CONCERN OF THE NIGHT WILL BE FOR THUNDERSTORMS AND POSSIBLE HEAVY
RAINFALL AND SEVERE WEATHER.

LATEST VISIBLE SATELLITE IMAGERY HAS A THIN BAND OF CLOUDS STRETCHING
FROM EXTREME NORTHEAST NEBRASKA TO NEAR LSE. SURFACE ANALYSIS HAS COLD
FRONT FROM JUST EAST OF MFI TO LSE TO JUST SOUTH OF EST. MUCH LOWER
DEWPOINTS IN THE 40S ADVECTING SOUTHEAST...WITH LOWER 70S SOUTH OF THE
FRONT. SOUNDER DERIVED PRODUCTS OF CAPE AND PRECIPITABLE WATER SHOW THE
BOUNDARY NICELY ALSO WITH NEAR 4000 J/KG CAPE VALUES JUST SOUTH AND
EAST OF THE FRONT AND FALLING QUICKLY TO NEAR 2000 J/KG NROTH OF THE
FRONT. PRECIPITABLE WATER VALUES NEAR 32 MM IN NORTHEAST IOWA AND
SOUTHWEST WISCONSIN.

LOOKING AT MODIFIED SOUNDINGS FROM ETA 12Z RUN...CAPE VALUES OF 4000 TO
5500 J/KG COMMON ACROSS NORTHEAST IOWA AND SOUTHWEST WISCONSIN THIS
EVENING BASED ON CURRENT SURFACE CONDITIONS. THESE VALUES LINING UP
WELL WITH CURRENT PROFILER PRODUCTS. ETA HAS PRECIPITABLE WATER VALUES
OF 1.25 TO 1.50 INCHES SOUTHERN PORTIONS OF THE FORECAST AREA. THERE IS
ONLY WEAK SPEED SHEAR. ETA APPEARS TO SLOWLY SAG THE FRONT SOUTH ACROSS
NORTHEAST IOWA AND SOUTHWEST WISCONSIN DURING THE NIGHT.  MOISTURE
TRANSPORT VECTORS AT 850 MB KEEP SAME REGIONS IN AREA OF GOOD INFLUX OF
MOISTURE THROUGH 06Z.  1000 TO 500 MB THICKNESS PATTERN IS DIFFLUENT
ACROSS SOUTHERN PORTIONS OF THE FORECAST AREA OVERNIGHT ALSO.

EXPECT CONVECTION TO INITIATE ALONG FRONTAL BOUNDARY THIS AFTERNOON AND
CONTINUE INTO THE OVERNIGHT HOURS. FRONT WILL ONLY MAKE SLOW PROGRESS
TO THE SOUTH AND SOUTHERN HALF OF FORECAST AREA MAY RECEIVE HEAVY
RAINFALL AMOUNTS.  ATMOSPHERE SEEMS TO SUPPORT LARGE HAIL AND STRONG
WINDS SOUTH OF THE FRONT.

NELSON

IAZ008>011-018-019-029-030-MNZ079-086>088-094>096-WIZ017-029-
032>034-041>044-053>055-061-291200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LA CROSSE WI
1045 AM CDT THU MAY 28 1998

...A SLIGHT CHANCE OF SEVERE THUNDERSTORMS THIS AFTERNOON INTO THE
EVENING...

THE STORM PREDICTION CENTER HAS INDICATED THERE IS A SLIGHT CHANCE OF
SEVERE THUNDERSTORMS ACROSS WESTERN WISCONSIN...SOUTHEAST MINNESOTA AND
NORTHEAST IOWA TODAY.  THE ATMOSPHERE IS EXPECTED TO BE VERY UNSTABLE
THIS AFTERNOON AS A SLOW MOVING COLD FRONT GRADUALLY MOVES INTO AND
THEN STALLS ACROSS SOUTHERN WISCONSIN AND NORTHEAST IOWA. AT 1000 AM
CDT...THE COLD FRONT WAS SITUATED FROM NEAR MSP TO JUST WEST OF MKT AND
SPW ANS WAS MOVING TO THE EAST.

THE COMBINATION OF THE UNSTABLE AIR MASS AND WEAK FRONT SHOULD BE ENOUGH
TO GENERATE THUNDERSTORMS THIS AFTERNOON INTO TONIGHT. THE MAIN THREAT
FROM THESE STORMS WILL BE LARGE HAIL AND DAMAGING WINDS. GIVEN THE VERY
UNSTABLE ATMOSPHERE...ISOLATED SUPERCELL THUNDERSTORMS MAY ALSO
DEVELOP. THE ABUNDANT MOISTURE IN THE ATMOSPHERE SHOULD ALSO HELP THE
STORMS PRODUCE HEAVY RAINFALL.

SPOTTER ACTIVATION MAY BE NECESSARY BY EARLY AFTERNOON AND LAST INTO
TONIGHT.

NELSON

IAZ008>011-018-019-029-030-MNZ079-086>088-094>096-WIZ017-029-
032>034-041>044-053>055-061-291200-

HAZARDOUS WEATHER OUTLOOK...CORRECTED FOR LOCATIONS.
NATIONAL WEATHER SERVICE LA CROSSE WI
1053 AM CDT THU MAY 28 1998

...A SLIGHT CHANCE OF SEVERE THUNDERSTORMS THIS AFTERNOON INTO THE
EVENING...

THE STORM PREDICTION CENTER HAS INDICATED THERE IS A SLIGHT CHANCE OF
SEVERE THUNDERSTORMS ACROSS WESTERN WISCONSIN...SOUTHEAST MINNESOTA AND
NORTHEAST IOWA TODAY.  THE ATMOSPHERE IS EXPECTED TO BE VERY UNSTABLE
THIS AFTERNOON AS A SLOW MOVING COLD FRONT GRADUALLY MOVES INTO AND
THEN STALLS ACROSS SOUTHERN WISCONSIN AND NORTHEAST IOWA. AT 1000 AM
CDT...THE COLD FRONT WAS SITUATED FROM NEAR MINNEAPOLIS TO JUST WEST OF
MANKAT0 MINNESOTA AND SPENSER IOWA AND WAS MOVING SLOWLY TO THE EAST.

THE COMBINATION OF THE UNSTABLE AIR MASS AND WEAK FRONT SHOULD BE ENOUGH
TO GENERATE THUNDERSTORMS THIS AFTERNOON INTO TONIGHT. THE MAIN THREAT
FROM THESE STORMS WILL BE LARGE HAIL AND DAMAGING WINDS. GIVEN THE VERY
UNSTABLE ATMOSPHERE...ISOLATED SUPERCELL THUNDERSTORMS MAY ALSO
DEVELOP. THE ABUNDANT MOISTURE IN THE ATMOSPHERE SHOULD ALSO HELP THE
STORMS PRODUCE HEAVY RAINFALL.

SPOTTER ACTIVATION MAY BE NECESSARY BY EARLY AFTERNOON AND LAST INTO
TONIGHT.

NELSON

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LA CROSSE WI
429 PM CDT THU MAY 28 1998

TIME(CDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0420 PM    ROCKFORD                  IA   .75 INCH HAIL
05/28/98   FLOYD                          3/4 TO ONE INCH HAIL NEAR
                                          ROCKFORD.

KRC