Severe Thunderstorm Warning 163, NWS La Crosse, WI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
733 AM CDT MON AUG 4 2008

.UPDATE...THIS MORNING

WATER VAPOR IMAGERY AND WIND PROFILERS SHOW A 500 MB SHORT WAVE
TROUGH MOVING NORTHEAST OF EASTERN NEBRASKA THIS MORNING. STRONG
TO SEVERE THUNDERSTORMS HAVE DEVELOPED AHEAD OF THIS TROUGH ACROSS
NORTHWEST IOWA. NONE OF THE MODELS ARE REALLY HANDLING THIS
SITUATION THAT WELL...SO I HAVE TO SHOOT FROM THE HIP AND LOOK AT
THE VARIOUS PARAMETERS ON THE SPC RUC. WITH MOST UNSTABLE CAPES OF
3000 TO 4000 J/KG AHEAD OF THIS THUNDERSTORM COMPLEX...I SEE NO
REASON WHY THIS COMPLEX WILL NOT CONTINUE TO MOVE TRHOUGH OUR AREA
THIS MORNING. IT APPEARS THAT THE THUNDERSTORMS WILL MOVE INTO
SOUTHEAST MINNESOTA AND NORTHEAST IOWA AROUND 14Z AND REACH THE
MISSISSIPPI RIVER BETWEEN 1030 AM AND 11 AM.

&&

.PREV DISCUSSION... /ISSUED 327 AM CDT MON AUG 4 2008/

SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT

FORECAST CONCERNS REMAIN ON PRECIPITATION CHANCES TODAY THROUGH
TUESDAY ALONG WITH SEVERE WEATHER THREAT.

07Z SURFACE ANALYSIS SHOWS A WEAK AREA OF LOW PRESSURE OVER
NORTHWEST IOWA...WITH WARM FRONT EXTENDING INTO THE FAR
SOUTHWESTERN SECTIONS OF THE FORECAST AREA. AREA PROFILERS SHOWING
SOUTHWESTERLY LOW LEVEL JET ACROSS IOWA FEEDING ELEVATED BAND OF
CONVECTION FROM NEAR LA CROSSE INTO CENTRAL WISCONSIN ALONG
THE EDGE OF THE CAPPING INVERSION.

04.00Z NCEP DETERMINISTIC MODELS SIMILAR IN THEIR SOLUTIONS WITH
SHORTWAVE ROTATING OUT OF CANADIAN TROUGH FLATTENING THE RIDGE
ACROSS THE NORTHERN TIER OF STATES. THIS ZONAL FLOW THEN SLOWLY
TRANSITIONS TO A MORE NORTHWESTERLY FLOW FOR THE GREAT LAKES REGION
BY TUESDAY AND WEDNESDAY. THE STRONGEST WAVE IN THE FLOW DROPS
ACROSS THE AREA TUESDAY AND WILL PUSH THE THE FRONT SOUTH OF THE
AREA.

IN THE NEAR TERM...04.06Z RUC INDICATES LOW LEVEL JET TO VEER TO A
MORE WESTERLY DIRECTION EARLY THIS MORNING. THUS EXPECT CONVECTION
TO BUILD SOUTHEASTWARD INTO SOUTHERN WISCONSIN BEFORE EXITING
LATER THIS MORNING. WEAK LOW PRESSURE WILL SLIDE NORTHEAST WITH WARM
FRONT LIFTING NORTHWARD. ONCE MORNING CONVECTION EXITS THE
AREA BETWEEN 11Z-13Z...WARM TEMPERATURES ALOFT WILL BE KEEP THE AREA
CAPPED MOST OF THE DAY. WITH INSTABILITY INCREASING THIS AFTERNOON
AND NEXT IMPULSE COULD SEE SOME SCATTERED CONVECTION DEVELOP.

FRONTAL BOUNDARY WILL RESIDE FROM NORTHEAST IOWA INTO SOUTHWEST
WISCONSIN TONIGHT. AS LOW LEVEL JET STRENGTHENS...POTENTIAL EXISTS
FOR ANOTHER MCS TO DEVELOP ALONG/NEAR THE FRONT AND MOVE EASTWARD
ACROSS THE AREA...ESPECIALLY AFFECTING NORTHEAST IOWA AND SOUTHWEST
WISCONSIN. AS THIS UNFOLDS LATER TODAY...LATER SHIFTS MAY BE ABLE TO
RAISE POPS INTO THE LIKELY CATEGORY FOR THE SOUTHERN SECTIONS OF THE
FORECAST AREA.

ON TUESDAY AS UPPER FLOW BECOME MORE NORTHWESTERLY ANOTHER
SHORTWAVE DROPS ACROSS THE AREA. THIS WILL PUSH ATTENDANT COLD FRONT
TO THE SOUTH OF THE AREA BY LATE AFTERNOON. BOTH GFS AND NAM SHOWING
MODERATE INSTABILITIES DEVELOPING ACROSS THE SOUTHERN SECTIONS OF THE
FORECAST AREA. WILL KEEP CHANCE POPS GOING WITH THE HIGHEST ACROSS
THE SOUTH. THE FRONT GETS PUSHED SOUTH OF THE AREA TUESDAY NIGHT AS
HIGH PRESSURE AND DRIER AIR ADVECT INTO THE AREA. DEW POINTS LOOK TO
DROP BACK INTO THE 50S UNDER CLEAR SKIES. WILL HAVE TO WATCH FOR FOG
POTENTIAL...ESPECIALLY GIVEN THE RECENT RAINS. FOR NOW WILL LEAVE OUT
THE GRIDS. DID DROP TEMPERATURES A LITTLE IN THIS TIME FRAME BASED ON
THE LOWER DEW POINTS AND CLEARING SKIES.

QUIET AND SEASONABLE WEATHER THEN SETTLES IN WEDNESDAY AND WEDNESDAY
NIGHT AS HIGH PRESSURE BUILDS INTO THE REGION.

LONG TERM...THURSDAY THROUGH SUNDAY

AREA WILL CONTINUE UNDER THE INFLUENCE OF NORTHWEST FLOW ALOFT.
THUS EXPECT TEMPERATURES TO BE NEAR OR SLIGHTLY BELOW NORMAL THROUGH
THE PERIOD. MAINLY A DRY PERIOD IS EXPECTED WITH THE EXCEPTION OF A
SHORTWAVE WAVE ON THURSDAY AFTERNOON...COMBINING WITH AFTERNOON
INSTABILITIES TO GENERATE SOME SHOWERS ACROSS THE NORTHEASTERN
ZONES AND THEN ANOTHER WAVE ON SUNDAY. PREVIOUS SET OF GRIDS HAVE
THE WILL IN HAND AND THUS PLAN NO CHANGES TO THIS PERIOD.

AVIATION...TODAY AND TONIGHT

THUNDERSTORMS WILL CONTINUE TO MOVE SOUTHEAST ACROSS WEST CENTRAL...
SOUTHWEST...AND CENTRAL WISCONSIN EARLY THIS MORNING...AND THEN MOVE
OUT OF THE AREA BETWEEN 11Z AND 13Z. THESE THUNDERSTORMS WILL HAVE
THE POTENTIAL OF PRODUCING LARGE HAIL AND DAMAGING WINDS.

FOR THE REMAINDER OF THE MORNING AND EARLY AFTERNOON...IT LOOKS LIKE
THE AREA WILL BE UNDER A STRONG CAP. THE CAP THEN WILL WEAKEN AS
SHORT WAVE TROUGH MOVES THROUGH THE REGION. AS THIS OCCURS...
THUNDERSTORMS WILL ONCE AGAIN DEVELOP ACROSS THE AREA. A FEW OF
THESE THUNDERSTORMS MAY BECOME SEVERE.

ADDITIONAL THUNDERSTORMS WILL BE POSSIBLE TONIGHT AS THE COLD FRONT
SINKS SOUTHWARD THROUGH THE AREA. A FEW OF THESE THUNDERSTORMS MAY
BECOME SEVERE. AT THIS TIME...IT LOOKS LIKE THESE THUNDERSTORMS MAY
BE SOUTH OF THE TAF SITES...SO MAY LEAVE THUNDER OUT OF THE TAFS.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&

UPDATE - BOYNE
SHORT AND LONG TERM - RABERDING
AVIATION - BOYNE

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LA CROSSE WI
525 AM CDT MON AUG 4 2008

IAZ008>011-018-019-029-030-MNZ079-086>088-094>096-WIZ017-029-032>034-
041>044-053>055-061-051100-
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-
525 AM CDT MON AUG 4 2008

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

.DAY ONE...TODAY AND TONIGHT

A FRONT WILL MEANDER ACROSS SOUTHERN MINNESOTA AND CENTRAL WISCONSIN
TODAY...AND THEN MOVE SLOWLY SOUTH INTO NORTHERN IOWA AND SOUTHERN
WISCONSIN TONIGHT. SEVERAL ROUNDS OF THUNDERSTORMS WILL MOVE ALONG
THIS FRONT. A FEW OF THESE THUNDERSTORMS MAY BECOME SEVERE SOUTH OF
A LINE FROM THE TWIN CITIES TO WISCONSIN RAPIDS. THE MAIN SEVERE
WEATHER THREATS WILL BE LARGE HAIL...DAMAGING WINDS...AND POSSIBLY
A FEW ISOLATED TORNADOES. THESE THUNDERSTORMS WILL ALSO BE CAPABLE OF
PRODUCING VERY HEAVY RAIN. THIS MAY RESULT IN LOCALIZED FLASH
FLOODING...ESPECIALLY IN URBAN AREAS AND STEEP TERRAIN...WHERE
RAINFALL RUNOFF WILL BE ENHANCED.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

THE FRONT WILL CONTINUE TO PROVIDE A CHANCE OF THUNDERSTORMS ON
TUESDAY AS YET ANOTHER WAVE OF LOW PRESSURE MOVES ALONG IT. NONE
OF THESE THUNDERSTORMS ARE EXPECTED TO BECOME SEVERE.

ADDITIONAL THUNDERSTORMS WILL BE POSSIBLE ON SUNDAY...BUT IT IS TOO
EARLY TO ASCERTAIN WHETHER ANY OF THESE THUNDERSTORMS WILL BECOME
SEVERE.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED PERIODICALLY FROM TODAY THROUGH
TONIGHT.

.EMERGENCY MANAGEMENT COORDINATION...

NO CALL IS SCHEDULED.

BOYNE

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LA CROSSE WI
629 AM CDT MON AUG 04 2008

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0224 AM     HAIL             ARCADIA                 44.25N 91.49W
08/04/2008  M0.88 INCH       TREMPEALEAU        WI   LAW ENFORCEMENT

&&

BOYNE

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LA CROSSE WI
917 AM CDT MON AUG 04 2008

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0908 AM     HAIL             5 SW MARBLE ROCK        42.91N 92.94W
08/04/2008  E0.75 INCH       FLOYD              IA   PUBLIC

            MOST HAIL WAS PEBBLE SIZE IN EXTREME SOUTHWEST PART OF
            COUNTY.

&&

SHEA

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LA CROSSE WI
924 AM CDT MON AUG 04 2008

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0920 AM     HAIL             1 E MARBLE ROCK         42.96N 92.85W
08/04/2008  E1.00 INCH       FLOYD              IA   PUBLIC

&&

BROOKS

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LA CROSSE WI
926 AM CDT MON AUG 04 2008

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0917 AM     HAIL             3 S MARBLE ROCK         42.92N 92.87W
08/04/2008  E0.50 INCH       FLOYD              IA   PUBLIC

&&

SHEA

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LA CROSSE WI
928 AM CDT MON AUG 04 2008

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0927 AM     HAIL             4 E MARBLE ROCK         42.96N 92.79W
08/04/2008  E1.00 INCH       FLOYD              IA   PUBLIC

            LOTS OF HAIL PENNY TO QUARTER SIZED FROM FARMS EAST OF
            TOWN.

&&

SHEA

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LA CROSSE WI
946 AM CDT MON AUG 04 2008

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0923 AM     HAIL             1 E MARBLE ROCK         42.96N 92.85W
08/04/2008  E1.00 INCH       FLOYD              IA   LAW ENFORCEMENT

            ALSO 50 MPH WIND GUSTS WITH A FEW TREES DOWN IN MARBLE
            ROCK

0916 AM     HAIL             MARBLE ROCK             42.96N 92.87W
08/04/2008  E0.88 INCH       FLOYD              IA   LAW ENFORCEMENT

0940 AM     HAIL             2 SW CHARLES CITY       43.05N 92.70W
08/04/2008  E0.75 INCH       FLOYD              IA   FIRE DEPT/RESCUE

&&

BROOKS