Severe Thunderstorm Warning 82, NWS La Crosse, WI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
325 PM CDT TUE JUN 13 2000

PRIMARY FORECAST CONCERNS FOR TONIGHT IS HEAVY RAINFALL AND SEVERE
WEATHER POTENTIAL.

SURFACE ANALYSIS SHOWS THAT THERE WAS A SURFACE WARM FRONT
JUST SOUTH OF THE CWA. HOWEVER...THE AIRMASS TO THE NORTH OF THIS
WARM FRONT HAS MODIFIED DURING THE DAY AND SURFACE DEW POINTS ARE
BECOMING SIMILAR ON BOTH SIDES OF THE WARM FRONT. IT APPEARS THAT
THIS WARM FRONT WILL SLOWLY WASH OUT THIS EVENING AND BECOME
REORGANIZED TO THE NORTH OF THE CWA. HOWEVER...THE AREA WILL BE
SEVERAL OUT FLOW BOUNDARIES FOR THE CONVECTION TO REFIRE IN THE WARM
SECTOR OF THE LOW PRESSURE AREA. ALSO...WATER VAPOR IMAGERY SHOW
FOUR SHORT WAVES ROTATING AROUND THE UPPER LEVEL TROUGH IN THE
CENTRAL PLAINS. THE FIRST SHORT WAVE IS CURRENTLY MOVING INTO
EASTERN IOWA. THIS SHORT WAVE IS RESPONSIBLE FOR THE CONVECTION
CURRENTLY OCCURRING ACROSS THE CWA. THE NEXT SHORT WAVE IS LOCATED
OVER EASTERN IOWA. THIS SHORT WAVE SHOULD BEGIN TO AFFECT THE
WESTERN PORTIONS OF THE CWA AROUND 6 PM. THE THIRD SHORT WAVE IS
JUST MOVING INTO WESTERN KANSAS AND THIS SHORT WAVE SHOULD BEGIN TO
AFFECT THE WESTERN PORTIONS OF THE CWA AROUND 10 PM. THE FINAL SHORT
WAVE IS CURRENTLY LOCATED OVER CENTRAL COLORADO...BUT THIS ONE WILL
BE VERY HARD TO TIME...BUT IT SHOULD ARRIVE DURING THE OVERNIGHT
HOURS. THE 12Z MODELS ONLY REALLY DETECTED THE FIRST TWO OF THESE
SHORT WAVES. THE MAIN THREAT WITH THESE STORMS WILL BE HEAVY RAIN.
ALSO...LARGE HAIL WILL BE A POSSIBILITY. HOWEVER...HIGH WINDS COULD
BECOME A FACTOR LATER ON TONIGHT IF WE BECOME FULLY ENTRENCHED IN
THE WARM SECTOR OF THIS SYSTEM.

ON WEDNESDAY...THE MODELS WERE IN GOOD AGREEMENT THAT THE FIRST COLD
FRONT WILL MOVE THROUGH THE CWA ON WEDNESDAY MORNING JUST AFTER
SUNRISE. ANOTHER COLD FRONT AND SHORT WAVE WILL SWING ACROSS THE CWA
ON WEDNESDAY AFTERNOON AND EVENING. WITH WET BULB ZEROS RUNNING AROUND
9000 FEET AND CAPES OF AROUND 1500 J/KG...WE COULD SEE HAIL
APPROACHING SEVERE LIMITS LATE IN THE AFTERNOON. EVEN THOUGH I WENT
LIKELY...THERE WILL BE A DRY PERIOD FROM MID MORNING THROUGH MID
AFTERNOON.

THANKS FOR COORDINATION WITH GRB...DMX...MPX...AND MKX.

.LSE...FLASH FLOOD WATCH...THIS AFTERNOON AND TONIGHT...
       NORTHEAST IOWA...IAZ008>011...018...019...029...030...
       SOUTHEAST MN...MNZ079...086>088...094>096...
       SOUTHWEST WI...WIZ032>034-041-042-053>055-061

BOYNE

IAZ008>011-018-019-029-030-MNZ079-086>088-094>096-WIZ017-029-032>034-
041>044-053>055-061-140430-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LA CROSSE WI
1230 PM CDT TUE JUN 13 2000

...SEVERE THUNDERSTORMS POSSIBLE ACROSS NORTHEAST IOWA...SOUTHEAST
MINNESOTA AND SOUTHWEST WISCONSIN THIS AFTERNOON AND TONIGHT...

A VIGOROUS UPPER LEVEL DISTURBANCE WILL MOVE ACROSS THE NORTHERN AND
CENTRAL PLAINS TODAY. THE ASSOCIATED SURFACE LOW WILL DEEPEN AS IT
MOVES INTO NORTHERN MINNESOTA TONIGHT. A STRONG SOUTHERLY LOW LEVEL
FLOW WILL PULL VERY MOIST AND UNSTABLE AIR NORTHWARD. IN ADDITION...
A WARM FRONT WILL LIFT NORTHWARD TOWARD THE AREA THIS AFTERNOON. DUE
TO THE THUNDERSTORMS CURRENTLY GOING ON ACROSS NORTHERN IOWA AND
SOUTHWEST WISCONSIN...THERE IS STILL SOME UNCERTAINTY AS TO HOW FAR
NORTH THIS FRONT WILL MAKE IT.

IF THE WARM FRONT MANAGES TO PUSH NORTH...AND SUNSHINE RETURNS...
RAPID DESTABILIZATION CAN BE EXPECTED...WITH THUNDERSTORMS QUICKLY
BECOMING SEVERE. THE MOST LIKELY AREAS FOR THIS WOULD BE ACROSS
NORTHEAST IOWA AND SOUTHWEST WISCONSIN. OTHERWISE...A SQUALL LINE IS
EXPECTED TO FORM ALONG THE COLD FRONT OVER WESTERN MINNESOTA THIS
AFTERNOON...AND THEN TRACK EAST ACROSS THE AREA THIS EVENING.
ALTHOUGH THE MAIN THREAT OF SEVERE WEATHER WILL BE LARGE HAIL AND
DAMAGING WINDS...A FEW TORNADOES WILL BE POSSIBLE ALONG THE WARM
FRONT. FLASH FLOODING IS ALSO POSSIBLE DUE TO HEAVY RAIN ANTICIPATED
WITH THE STORMS.

AT THIS TIME...SPOTTER ACTIVATION WILL LIKELY BE NEEDED BY MID
AFTERNOON ACROSS NORTHEAST IOWA...AND OVER THE REMAINDER OF
SOUTHEAST MINNESOTA AND SOUTHWEST WISCONSIN LATE THIS AFTERNOON
AND THROUGH THE EVENING.

THOMPSON