Damaging Winds in Wisconsin, July 23, 2005

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
353 AM CDT SAT JUL 23 2005

.SHORT TERM...THROUGH MONDAY

MAIN FORECAST CONCERN IS WITH THE RAIN CHANCES THROUGH MUCH OF THE
PERIOD.

SURFACE ANALYSIS THIS MORNING SHOWS AN AREA OF DEVELOPING LOW
PRESSURE OVER NORTHEAST WYOMING. WARM FRONT EXTENDS EAST/SOUTHEAST
INTO WESTERN IOWA AND THEN BECOMES MORE DIFFUSE OVER NORTHWEST
MISSOURI. A FEW SHOWERS WERE DEVELOPING NORTH OF THE 850 MB WARM
FRONT OVER SOUTHEAST MINNESOTA INTO SOUTHWEST WISCONSIN.

00Z MODELS PRESENT VERY DIFFERENT SOLUTIONS FOR TODAY. THE GFS HAS
BEEN THE MOST CONSISTENT AND AT THIS TIME IS THE PREFERRED
SOLUTION. THE SHORT WAVE TROUGH CURRENTLY OVER THE HIGH PLAINS WILL
MOVE EAST ALONG THE CANADIAN BORDER TODAY AND TONIGHT IN THE ZONAL
FLOW ALOFT. SURFACE LOW IS EXPECTED TO TRANSLATE EAST AS WELL AND
BE OVER EASTERN MINNESOTA OR WESTERN WISCONSIN BY LATE TONIGHT. THE
WARM FRONT IS EXPECTED TO LIFT NORTH INTO THE FORECAST AREA THIS
AFTERNOON AND THEN HALT ITS NORTHWARD ADVANCE OVERNIGHT. SHOWERS AND
STORMS CURRENTLY OVER THE AREA DEVELOPING IN RESPONSE TO THE LOW
LEVEL MOISTURE TRANSPORT INTO THE 850 MB WARM FRONT AND THE RESULTING
ISENTROPIC LIFT. AS THE SHORT WAVE TROUGH AND SURFACE MOVE EAST TODAY
AND TONIGHT...THE BEST WARM AIR ADVECTION WILL LIFT SLOWLY NORTH AND
EAST INTO NORTHERN AND EASTERN WISCONSIN. IN RESPONSE...THE GFS SHOWS
THE AREA OF 5 TO 6 UBAR/S OF UPGLIDE ON THE 310K ISENTROPIC SURFACE
ALSO SHIFTING SLOWLY NORTH AND EAST. WITH MUCH OF THE FORECAST AREA
EXPECTED TO REMAIN NORTH OF THE WARM FRONT TODAY...THE ISENTROPIC
FORCING WILL CONTINUE TO IMPACT THE AREA AND GENERATE CLOUD COVER AND
SCATTERED SHOWERS AND THUNDERSTORMS. DEBRIS CLOUDS FROM CONVECTIVE
COMPLEX OVER THE DAKOTAS HAVE ALSO BEEN SPREADING INTO THE AREA AND
THICKENING...SO TREND IS FOR LESS SUNSHINE THAN PREVIOUS FORECAST AND
AS A RESULT LOWER TEMPERATURES.

THE BEST ISENTROPIC UPGLIDE SHIFTS OUT OF THE AREA TONIGHT...BUT
COULD CONTINUE ACROSS THE NORTH AND EAST AND DID CONTINUE CHANCE POPS
ACROSS THIS AREA THROUGH THE NIGHT. THE SURFACE LOW GOES PAST SUNDAY
ALLOWING THE WEAK COLD FRONT TO COME THROUGH THE AREA DURING THE
MORNING AND EARLY AFTERNOON. NO SHORT WAVE TROUGHS ARE EXPECTED TO BE
OVER THE REGION TO PROVIDE ANY DYNAMICAL FORCING AS THE FRONT COMES
THROUGH AND WITH SURFACE BASED CINS OF 100 J/KG OVER MUCH OF THE
AREA...MAINTAINED THE DRY FORECAST FOR SUNDAY. DESPITE THE PASSAGE OF
THE FRONT...TEMPERATURES AT 850 MB ONLY COOL 1-2C DURING THE DAY ON
WEAK NORTHWEST WINDS. SO WITH MORE SUNSHINE...TEMPERATURES SUNDAY
EXPECTED TO BE WARMER THAN TODAY.

THE FRONT IS THEN EXPECTED TO BECOME STATIONARY JUST SOUTH OF THE
FORECAST AREA SUNDAY NIGHT. THE UPPER LEVEL RIDGE WILL SINK JUST
FAR ENOUGH SOUTH TO ALLOW THE SHORT WAVE TROUGHS EMBEDDED IN THE
ZONAL FLOW TO AFFECT THE UPPER MIDWEST. ONE OF THESE SHORT WAVE
TROUGHS WILL MOVE ALONG THE BAROCLINIC ZONE SUNDAY NIGHT AND
INTERACT WITH THE LOW LEVEL MOISTURE TRANSPORT TO DEVELOP CONVECTION
NORTH OF THE STALLED FRONTAL BOUNDARY. THIS ACTIVITY EXPECTED TO
MOVE ACROSS THE FORECAST AREA AND RAISED POPS FROM PREVIOUS
FORECAST FOR SUNDAY NIGHT INTO MONDAY MORNING. IF CURRENT MODEL
TRENDS CONTINUE...THESE WILL HAVE TO BE RAISED MORE WITH LATER
SHIFTS.

.LONG TERM...MONDAY NIGHT THROUGH FRIDAY

THE GFS SUGGESTS ANOTHER MCS WILL DEVELOP NORTH OF THE STALLED FRONT
MONDAY NIGHT AND MOVE ACROSS NORTHERN IOWA INTO SOUTHERN WISCONSIN
BY TUESDAY MORNING. THE FRONT THEN GETS PUSHED SOUTH OF THE AREA AS
HIGH PRESSURE BUILDS INTO THE UPPER MIDWEST. RAISED POPS FOR MONDAY
NIGHT TO AGREE WITH WITH LATEST MODEL TRENDS AND SURROUNDING
OFFICES. ALSO LOWERED TEMPERATURES ACROSS THE SOUTH FOR TUESDAY WITH
PLENTY OF CLOUD COVER AND RAIN EXPECTED IN THE MORNING. REMAINDER OF
THE CURRENT FORECAST LOOKS OK AND NO CHANGES MADE.

&&

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

04

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LA CROSSE WI
915 AM CDT SAT JUL 23 2005

IAZ008>011-018-019-029-030-MNZ094>096-WIZ053>055-061-240900-
ALLAMAKEE-CHICKASAW-CLAYTON-CRAWFORD-FAYETTE-FILLMORE-FLOYD-GRANT-
HOUSTON-HOWARD-MITCHELL-MOWER-RICHLAND-VERNON-WINNESHIEK-
915 AM CDT SAT JUL 23 2005

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

.DAY ONE...TODAY AND TONIGHT

A WARM FRONT WILL LIFT NORTHEAST ACROSS THE AREA TODAY. A MOIST AND
UNSTABLE AIRMASS BEING LIFTED OVER THE FRONT WILL TRIGGER
THUNDERSTORMS ACROSS THE AREA...MAINLY THIS MORNING. THE MAIN THREAT
FROM ANY THUNDERSTORMS TODAY WOULD BE LARGE HAIL. ONCE THE WARM FRONT
MOVES THROUGH THE AREA...WARM TEMPERATURES ALOFT SHOULD CAP THE
AIRMASS AND LIMIT THUNDERSTORM POTENTIAL THIS AFTERNOON INTO TONIGHT.

BEHIND THE WARM FRONT...HEAT INDICES THIS AFTERNOON ARE EXPECTED TO
CLIMB INTO THE 100 TO 105 DEGREE RANGE...MAINLY ACROSS PORTIONS OF
NORTHEAST IOWA. PROLONGED EXPOSURE TO THIS HEAT COULD CAUSE PHYSICAL
PROBLEMS...SUCH AS HEAT EXHAUSTION.

A COLD FRONT WILL APPROACH THE AREA LATE TONIGHT. WITH MOISTURE AND
INSTABILITY IN PLACE AHEAD OF THE FRONT...THERE IS THE POTENTIAL FOR
MORE THUNDERSTORM DEVELOPMENT. HOWEVER...THE WARM TEMPERATURES ALOFT
MAY KEEP THE AIRMASS CAPPED AND LIMIT THE THUNDERSTORM POTENTIAL.
SHOULD ANY THUNDERSTORMS DEVELOP...THE SEVERE THREATS WOULD BE LARGE
HAIL AND DAMAGING WINDS.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

THE COLD FRONT WILL DROP SOUTH OF THE AREA SUNDAY AS A WEAK RIDGE
OF HIGH PRESSURE BUILDS OVER THE AREA. HEAT INDICES ON SUNDAY ARE
AGAIN EXPECTED TO CLIMB INTO THE 100 TO 105 DEGREE RANGE ACROSS
THE SOUTH PARTS OF THE AREA AND IN THE RIVER VALLEYS.

THE FRONTAL BOUNDARY IS EXPECTED TO WAVER BACK AND FORTH ACROSS IOWA
AND NORTHERN ILLINOIS SUNDAY NIGHT THROUGH MONDAY NIGHT...TRIGGERING
MORE THUNDERSTORMS. THE EXACT DETAILS ON THE TIMING AND AREAL
COVERAGE OF STORMS SUNDAY NIGHT THROUGH MONDAY NIGHT REMAIN UNCERTAIN
AT THIS TIME. HOWEVER...SOME OF THESE STORMS COULD BE SEVERE WITH
LARGE HAIL...DAMAGING WINDS AND FLASH FLOOD PRODUCING RAINS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED TODAY AND LATE TONIGHT. SPOTTER
GROUPS ARE ADVISED TO REMAIN ALERT FOR POSSIBLE ACTIVATION SUNDAY
NIGHT THROUGH MONDAY NIGHT.

.EMERGENCY MANAGEMENT COORDINATION...

NO CALL IS SCHEDULED.

MNZ079-086>088-WIZ017-029-032>034-041>044-240900-
ADAMS-BUFFALO-CLARK-DODGE-JACKSON-JUNEAU-LA CROSSE-MONROE-OLMSTED-
TAYLOR-TREMPEALEAU-WABASHA-WINONA-
915 AM CDT SAT JUL 23 2005

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST
MINNESOTA AND WEST INTO CENTRAL WISCONSIN.

.DAY ONE...TODAY AND TONIGHT

A CLUSTER OF THUNDERSTORMS WILL TRACK ACROSS CENTRAL AND EASTERN
MINNESOTA THIS MORNING...PUSHING INTO NORTHERN WISCONSIN BY NOON.
THIS CLUSTER OF THUNDERSTORMS HAS A HISTORY OF PRODUCING DAMAGING
WINDS. LARGE HAIL WILL ALSO BE POSSIBLE. THE THUNDERSTORMS SHOULD
MAINLY EFFECT AREAS NORTH OF A WABASHA TO BLACK RIVER FALLS LINE...
EXITING EAST OF THE AREA EARLY IN THE AFTERNOON.

MEANWHILE...A WARM FRONT WILL LIFT NORTHEAST ACROSS THE AREA TODAY. A
MOIST AND UNSTABLE AIRMASS BEING LIFTED OVER THE FRONT WILL LIKELY
TRIGGER MORE THUNDERSTORMS ACROSS THE AREA THIS AFTERNOON AND
EVENING. SEVERE WEATHER THREATS WOULD AGAIN BE DAMAGING WINDS AND
LARGE HAIL. THE STORM PREDICTION CENTER HAS INDICATED THERE IS A
MODERATE RISK FOR SEVERE WEATHER TODAY AND TONIGHT.

A COLD FRONT WILL APPROACH THE AREA THEN LATE TONIGHT. WITH MOISTURE
AND INSTABILITY IN PLACE AHEAD OF THE FRONT...THERE IS THE POTENTIAL
FOR MORE THUNDERSTORM DEVELOPMENT. HOWEVER...THE WARM TEMPERATURES
ALOFT MAY KEEP THE AIRMASS CAPPED AND LIMIT THE THUNDERSTORM
POTENTIAL. SHOULD ANY THUNDERSTORMS DEVELOP...THE SEVERE THREATS
WOULD BE LARGE HAIL AND DAMAGING WINDS.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

THE COLD FRONT WILL DROP SOUTH OF THE AREA SUNDAY AS A WEAK RIDGE
OF HIGH PRESSURE BUILDS OVER THE AREA. HEAT INDICES ON SUNDAY ARE
AGAIN EXPECTED TO CLIMB INTO THE 100 TO 105 DEGREE RANGE ACROSS
THE SOUTH PARTS OF THE AREA AND IN THE RIVER VALLEYS.

THE FRONTAL BOUNDARY IS EXPECTED TO WAVER BACK AND FORTH ACROSS IOWA
AND NORTHERN ILLINOIS SUNDAY NIGHT THROUGH MONDAY NIGHT...TRIGGERING
MORE THUNDERSTORMS. THE EXACT DETAILS ON THE TIMING AND AREAL
COVERAGE OF STORMS SUNDAY NIGHT THROUGH MONDAY NIGHT REMAIN UNCERTAIN
AT THIS TIME. HOWEVER...SOME OF THESE STORMS COULD BE SEVERE WITH
LARGE HAIL...DAMAGING WINDS AND FLASH FLOOD PRODUCING RAINS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED TODAY AND TONIGHT. SPOTTER
GROUPS ARE ADVISED TO REMAIN ALERT FOR POSSIBLE ACTIVATION SUNDAY
NIGHT THROUGH MONDAY NIGHT.

.EMERGENCY MANAGEMENT COORDINATION...

NO CALL IS SCHEDULED.

RIECK/RRS

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
1019 AM CDT SAT JUL 23 2005

MNZ079-086>088-WIZ017-029-032>034-041>044-232100-
ADAMS-BUFFALO-CLARK-DODGE-JACKSON-JUNEAU-LA CROSSE-MONROE-OLMSTED-
TAYLOR-TREMPEALEAU-WABASHA-WINONA

THE NATIONAL WEATHER SERVICE HAS ISSUED SEVERE THUNDERSTORM WATCH
663 IN EFFECT UNTIL 4 PM CDT FOR THE FOLLOWING AREAS

IN MINNESOTA THIS WATCH INCLUDES 4 COUNTIES

IN SOUTHEAST MINNESOTA

DODGE                 OLMSTED               WABASHA
WINONA

IN WISCONSIN THIS WATCH INCLUDES 9 COUNTIES

IN CENTRAL WISCONSIN

ADAMS                 CLARK                 JUNEAU

IN NORTH CENTRAL WISCONSIN

TAYLOR

IN WEST CENTRAL WISCONSIN

BUFFALO               JACKSON               LA CROSSE
MONROE                TREMPEALEAU

THIS INCLUDES THE CITIES OF...DODGE CENTER...FRANKLIN...
GLENDALE...INDEPENDENCE...LA CROSSE...MAUSTON...MEDFORD...
NEILLSVILLE...ONALASKA...ROCHESTER...WABASHA AND WINONA.