Severe Thunderstorm Warning 86, NWS La Crosse, WI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
305 PM CDT SAT JUN 12 2004

.SHORT TERM...THROUGH MONDAY NIGHT

FORECAST CONCERNS REMAIN ON RAIN CHANCES...FLOODING AND SEVERE
WEATHER THREAT NEXT SEVERAL DAYS.

19Z SURFACE ANALYSIS SHOWS WEAK RESIDUAL BOUNDARY EXTENDING FROM
NORTH CENTRAL MINNESOTA...SOUTHWARD TO SOUTHEAST MINNESOTA...AND
INTO CENTRAL IOWA...TO AN AREA OF LOW PRESSURE IN KANSAS. CONVECTION
HAS FORMED ACROSS EASTERN NEBRASKA EARLIER THIS MORNING AND WAS NOW
MOVING INTO WESTERN IOWA. MEANWHILE WATER VAPOR IMAGERY SHOWING
SHORTWAVE IN NORTHERN STREAM ACROSS SOUTHERN CANADA.

12Z 12JUN04 MODELS IN REASONABLE AGREEMENT THROUGH 60 HOURS...AFTER
WHICH SOME DIFFERENCES APPEAR WITH RESPECT TO NORTHERN STREAM WAVE
TO AFFECT THE AREA EARLY NEXT WEEK. GFS CONTINUES TO HAVE SOME
NOTICEABLE AND SEEMINGLY INCORRECT CONVECTIVE FEEDBACK ISSUES TONIGHT
AND AGAIN SUNDAY NIGHT OVER THE REGION...AND THIS SKEWS SOME OF ITS
MASS FIELDS IN A DETRIMENTAL WAY. THUS HAVE FOLLOWED THE ETA FOR
THE MOST PART.

CURRENT CONVECTION ACROSS WESTERN IOWA SHOULD CONTINUE TO PUSH EAST-
NORTHEAST ACROSS IOWA THIS EVENING. MEANWHILE...NORTHERN STREAM
SHORTWAVE TO ROTATE ALONG THE U.S. CANADIAN BORDER. STRONGEST LOW
LEVEL JET AND MOISTURE TRANSPORT TO REMAIN TO OUR SOUTH WHERE
GREATEST THREAT OF SEVERE WEATHER AND HEAVY RAINS RESIDE. HOWEVER...
RUC IS SHOWING SOME MOISTURE TRANSPORT LATER TONIGHT UP ACROSS
MINNESOTA...AND FEEL THAT THESE TWO AREAS WILL MERGE GIVING AREA
ANOTHER GOOD CHANCE FOR RAINFALL. SHEAR PROFILES REMAIN RATHER
WEAK WITH WEAK TO MODERATE INSTABILITIES OVER THE FORECAST AREA...SO
THINK SEVERE THREAT IS RATHER LIMITED. WITH CONVECTION TO THE SOUTH
INTERCEPTING MOISTURE AND BOUNDARY BEING RATHER WEAK AND DIFFUSE...
NOT EXPECTING ANY WIDESPREAD HEAVY RAIN...ALTHOUGH LOCALLY HEAVY
RAIN IS STILL POSSIBLE. FOR NOW WILL HOLD OFF ON ANY FLOOD WATCH
BUT THIS WILL HAVE TO BE MONITORED THIS EVENING.

RAIN TO LINGER INTO SUNDAY MORNING THEN WAVE FINALLY PUSHES EAST BY
AFTERNOON. QUESTION FOR AFTERNOON/EVENING CONVECTION WILL BE
LOCATION OF BOUNDARY. ETA SHOWING 1000 TO 2000 J/G CAPES BY
AFTERNOON WITH 0-6KM SHEAR VALUES 35 TO 40 KNOTS. WILL CONTINUE THE
CHANCE POPS INTO THE EVENING HOURS BASED ON THIS. GIVEN THE AMOUNT
OF INSTABILITY AND SHEAR...WOULD EXPECT A RATHER GOOD CHANCE FOR
SOME SEVERE STORMS.

NEXT WAVE THEN TO AFFECT THE AREA MONDAY NIGHT INTO TUESDAY AND
CHANCE POPS LOOKS GOOD FOR THIS TIME FRAME PER PREVIOUS FORECAST.

AS FOR TEMPERATURES...GUIDANCE VALUES SIMILAR...EXCEPT FOR SUNDAY...
WHERE MET A LITTLE COOLER. QUESTION FOR THIS DAY WILL BE TIMING OF
RAIN MOVING. TOOK MORE OF A COMPROMISE BETWEEN THE GUIDANCE NUMBERS.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

FAST NEARLY ZONAL FLOW ACROSS THE NORTHERN TIER OF STATES WILL
GRADUALLY SHIFT TO A EASTERN TROUGH WESTERN RIDGE BY SATURDAY.
CONFIDENCE IS LOW WITH HANDLING THE INDIVIDUAL SHORTWAVES WITHIN
THE FLOW. MEDIUM RANGE MODELS ARE CONSISTENT WITH BRINGING A FRONT
ACROSS ON WEDNESDAY...SO WILL ADD POPS TO THIS TIME FRAME. BEYOND
THAT POSITIONING OF FRONT AND AFOREMENTIONED SHORTWAVES WILL IMPACT
OUR RAIN CHANCES. TODAYS MODEL RUNS INDICATE FRONT TO PUSH SOUTH OF
THE AREA AND KEEP AREA MAINLY DRY BEYOND WEDNESDAY. THIS ALREADY
COVERED IN CURRENT GRIDS AND WILL NOT MAKE ANY CHANGES AT THIS TIME.

&&

.ARX...WATCHES/WARNING/ADVISORIES...
IA...NONE.
MN...NONE.
WI...NONE.

&&

RABERDING

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LA CROSSE WI
528 AM CDT SAT JUN 12 2004

IAZ008>011-018-019-029-030-MNZ079-086>088-094>096-WIZ017-029-032>034-
041>044-053>055-061-131100-
ADAMS-ALLAMAKEE-BUFFALO-CHICKASAW-CLARK-CLAYTON-CRAWFORD-DODGE-
FAYETTE-FILLMORE-FLOYD-GRANT-HOUSTON-HOWARD-JACKSON-JUNEAU-LA CROSSE-
MITCHELL-MONROE-MOWER-OLMSTED-RICHLAND-TAYLOR-TREMPEALEAU-VERNON-
WABASHA-WINNESHIEK-WINONA-
528 AM CDT SAT JUN 12 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PARTS OF SOUTHEAST
MINNESOTA...NORTHEAST IOWA...AND CENTRAL AND SOUTHWEST WISCONSIN.

.DAY ONE...TODAY AND TONIGHT

SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP LATE THIS AFTERNOON
ACROSS SOUTHWEST AND WEST CENTRAL MINNESOTA ALONG A FRONTAL BOUNDARY
TO OUR SOUTH AND WEST. AS THESE THUNDERSTORMS MOVE EAST...THEY
MAY AFFECT THE AREA THIS EVENING.

A FEW OF THESE THUNDERSTORMS MAY BECOME SEVERE BETWEEN 6 PM AND
MIDNIGHT. THE MAIN SEVERE WEATHER THREAT WILL BE HAIL UP TO ONE INCH
IN DIAMETER AND WIND GUSTS IN THE EXCESS OF 58 MPH.

LOOKING FURTHER TO OUR SOUTHWEST...A THUNDERSTORM COMPLEX IS EXPECTED
TO DEVELOP ACROSS EASTERN NEBRASKA...EASTERN KANSAS...AND NORTHERN
MISSOURI DURING THIS EVENING AND THEN MOVE NORTHEAST THROUGH THE AREA
AFTER MIDNIGHT TONIGHT. DEPENDING ON THE EXACT TRACK OF THIS
THUNDERSTORM COMPLEX...IT MAY AGGRAVATE THE FLOODING SITUATION
ACROSS THE AREA.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

THUNDERSTORMS MAY BE ONGOING ON SUNDAY MORNING AS THE THUNDERSTORM
COMPLEX OVERNIGHT TONIGHT CONTINUES TO MOVE NORTHEAST AWAY FROM THE
AREA. THE DEBRIS CLOUDS LEFT BEHIND BY THESE THUNDERSTORMS WILL
LIKELY LIMIT THE INSTABILITY ACROSS THE AREA DURING THE DAY.

HOWEVER...IF WE ARE ABLE TO RECOVER ON SUNDAY AFTERNOON BEFORE
AN UPPER LEVEL TROUGH MOVES EAST THROUGH THE REGION DURING THE
EVENING...THE AREA MAY SEE ANOTHER BOUT OF SEVERE WEATHER. THE
WIND SHEAR WILL BE SUFFICIENT FOR THE DEVELOPMENT OF SCATTERED
SUPERCELL THUNDERSTORMS ON SUNDAY AFTERNOON AND EVENING. THE MAIN
SEVERE WEATHER THREAT WILL BE LARGE HAIL AND DAMAGING WINDS.

ADDITIONAL THUNDERSTORMS MAY DEVELOP ACROSS THE AREA ON MONDAY
AFTERNOON AND EVENING AS YET ANOTHER UPPER LEVEL TROUGH MOVES EAST
ACROSS THE REGION. AT THIS TIME...IT APPEARS THAT THE BEST THREAT OF
SEVERE WEATHER WILL BE ACROSS IOWA AND SOUTHERN WISCONSIN WHERE
LARGE HAIL AND DAMAGING WINDS WILL BE THE PRIMARY THREATS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED THIS EVENING...AND AGAIN ON
SUNDAY AND MONDAY DURING THE AFTERNOON AND EVENING. IN ADDITION...
RAINFALL REPORTS WOULD BE APPRECIATED.

.EMERGENCY MANAGEMENT COORDINATION...

NO CALL IS SCHEDULED.

BOYNE