Severe Thunderstorm Warning 50, NWS La Crosse, WI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
439 AM CDT WED MAY 31 2000

TIMING OF THE SHORT WAVES...THE POSSIBILITY OF FLOODING AND SEVERE
WEATHER...AND HOW WARM WILL IT GET ON THURSDAY ARE THE PRIMARY
FORECAST CONCERNS WITH THIS PACKAGE.

THE MODELS ARE CONTINUING TO HAVE PROBLEMS HANDLING THE SHORT WAVES
THIS MORNING. THEY SHOW A WIDE VARIETY OF SOLUTIONS AND IN ACTUALITY
NONE OF THEM ARE REALLY DOING A GREAT JOB. AS A RESULT...WILL HAVE
TO RESORT TO LOOKING AT WATER VAPOR IMAGERY IN ORDER TO DETERMINE
WHEN NEXT CLUSTER OF THUNDERSTORMS WILL AFFECT THE AREA. LOOKING AT
THE WATER VAPOR IMAGERY...THERE ARE SEVERAL EMBEDDED VORT MAXES
LOCATED IN THE SOUTHWEST FLOW. SO IT LOOKS LIKE A BROAD BRUSH OF
SHOWERS AND THUNDERSTORMS IN THE FORECAST WILL WORK THE BEST AND
WILL ALSO PUT HIGHER POPS IN THE VICINITY OF THE SURFACE FRONT.

THE WATER VAPOR IMAGERY ALSO SHOWS THAT THERE IS A TROPICAL
CONNECTION WITH THIS SYSTEM. THE MODELS DO PICK UP ON THIS VERY
WELL. THEY SHOW CLIMATOLOGICALLY HIGH PRECIPITABLE WATERS ACROSS THE
REGION THROUGH THE FORECAST PERIOD. AS A RESULT...FLOODING IS A
CONCERN...BUT IT WILL MOST LIKELY BE TONIGHT WHEN THE MODELS SHOW
THAT A MCS WILL DEVELOP ACROSS NORTHWEST IOWA. CORFIDI VECTORS SHOW
THAT THIS SYSTEM WILL MOVE EAST NEAR THE MINNESOTA AND IOWA BOARDER.
RAINFALL AMOUNTS COULD EASILY GET INTO THE 2 TO 4 INCH RANGE...BUT
SINCE THE MODELS HAVE BEEN HAVING PROBLEMS PUTTING THESE MCSS IN
THE RIGHT SPOT...I HAVE OPTED TO LET DAY SHIFT ISSUE A FLASH FLOOD
WATCH IF IT IS NEEDED FOR TONIGHT.

BESIDES FLOODING...WE WILL ALSO HAVE TO WATCH OUT FOR PULSE SEVERE
STORMS. SINCE THE CWA IS ON THE NORTH SIDE OF THE FRONT...THE
PRIMARY CONCERN WILL BE LARGE HAIL. THESE THUNDERSTORMS WILL BE
PULSE SEVERE...SO WARNINGS COULD BE COMING OUT OF THE OFFICE AT ANY
TIME DURING THE NEXT 36 HOURS. WITH FREEZING LEVELS OF AROUND
14,000 FEET...SEVERE HAIL WILL BE POSSIBLE WITH 50-55 DBZ CORES OF
ABOVE 32,000 FEET. THUNDERSTORM MOTION WILL BE EAST AT 30 MPH.

ALL OF THE MODELS SHOW THAT A WARM FRONT WILL MOVE NORTHWARD TONIGHT
AND THURSDAY. HOWEVER...THEY DISAGREE SOME WHAT ON THE TIMING. THE
NGM MOVES THIS FRONT THE FASTEST TO THE NORTH. MEANWHILE...THE AVN
AND ETA MODELS ARE SLIGHTLY SLOWER. WITH THE ETA HAVING GREATER LOW
LEVEL RESOLUTION...I WENT WITH THE ETAS MOVEMENT.

.LSE...NONE.

BOYNE

IAZ008>011-018-019-029-030-MNZ079-086>088-094>096-WIZ032>034-041>044-
053>055-061-311800-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LA CROSSE WI
653 AM CDT WED MAY 31 2000

...SLIGHT RISK OF SEVERE THUNDERSTORMS CONTINUES...

SCATTERED THUNDERSTORMS ACROSS SOUTHWEST WISCONSIN AND NORTHEAST IOWA
WILL CONTINUE TO WEAKEN THIS MORNING.  AT 645 AM...UPSTREAM ACROSS
WESTERN IOWA AND MINNESOTA...ANOTHER COMPLEX OF THUNDERSTORMS
CONTINUES TO MOVE TOWARD THE AREA.  THESE STORMS ARE THE RESULT OF
STRONG LOW LEVEL WINDS FLOWING ACROSS A STATIONARY SURFACE FRONT.  AS
THE MORNING WEARS ON...THESE LOW LEVEL WINDS WILL WEAKEN CAUSING THE
STORMS WEAKEN AS WELL.  HOWEVER...BEFORE THIS OCCURS THESE STORMS MAY
STILL POSE THE THREAT OF BECOMING SEVERE SHOULD THEY STAY TOGETHER...
ARRIVING MID-MORNING ACROSS SOUTHEAST MINNESOTA AND NORTHEAST
IOWA.  THESE STORMS SHOULD TRACK NORTHEASTWARD DURING THE DAY INTO
WISCONSIN.

THE STATIONARY SURFACE BOUNDARY IS EXPECTED TO REMAIN TO OUR SOUTH
TODAY...AND GRADUALLY MOVE NORTH AS A WARM FRONT THIS AFTERNOON AND
EVENING.  AS THIS OCCURS...THE ATMOSPHERE WILL BECOME QUITE
UNSTABLE.  THUNDERSTORMS WILL DEVELOP SOUTH OF THIS BOUNDARY...WHICH
BY EVENING SHOULD BE LOCATED ACROSS CENTRAL IOWA AND NORTHERN
ILLINOIS.  SOME OF THESE THUNDERSTORMS COULD BE SEVERE WITH THE MAIN
THREAT BEING LARGE HAIL AND DAMAGING WIND.  ISOLATED TORNADOES ARE
ALSO POSSIBLE SOUTH OF THE BOUNDARY.

AS EVENING ARRIVES...DEVELOPMENT OF THUNDERSTORMS WILL SHIFT NORTH OF
THIS FRONT.  SOME OF THESE STORMS MAY BE SEVERE WITH THE MAIN THREAT
BEING LARGE HAIL.

SPOTTER ACTIVATION MAY BE NEEDED DURING THE MID TO LATE MORNING...BUT
MORE LIKELY THIS EVENING AND TONIGHT.  STAY TUNED FOR LATER UPDATES
REGARDING THE WEATHER SITUATION.

KRC

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LA CROSSE WI
753 AM CDT WED MAY 31 2000

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

1100 PM    5 E POSTVILLE             IA   0.75 INCH HAIL
05/30/00   ALLAMAKEE                      REPORTED BY GENERAL PUBLIC

1215 AM    SOLDIERS GROVE            WI   0.75 INCH HAIL
05/31/00   CRAWFORD                       REPORTED BY GENERAL PUBLIC

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LA CROSSE WI
853 AM CDT WED MAY 31 2000

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

1200 AM    MT STERLING               WI   .75 INCH HAIL
05/31/00   CRAWFORD                       REPORTED BY COOP OBSERVER.

0310 AM    CAZENOVIA                 WI   .75 INCH HAIL
05/31/00   RICHLAND                       REPORTED BY POST OFFICE AND
                                          MAIL CARRIERS.

SHEA

N