Hail in Wisconsin, May 11, 2002

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
225 PM CDT SAT MAY 11 2002

FORECAST CONCERNS WILL PRIMARILY BE WITH RAINFALL AND WIND TREND
TONIGHT...THEN CLOUD TRENDS AND LINGERING RAIN CHANCES ON SUNDAY.

SURFACE ANALYSIS INDICATED LOW PRESSURE OVER KANSAS...WITH FRONT
EXTENDING ACROSS NORTHERN MISSOURI INTO SOUTHERN ILLINOIS. RAIN
DECREASING IN COVERAGE OVER MOST OF THE FORECAST AREA. TIGHT PRESSURE
GRADIENT PRODUCING STRONG EAST WINDS ACROSS PORTIONS OF SOUTHEAST MN
AND NORTHEAST IOWA...WHERE GUSTS OF 40 TO 50 MPH HAVE OCCURRED.

12Z MODELS INITIALIZED FAIRLY WELL...WITH AVN AND ETA GENERALLY IN
GOOD AGREEMENT ON OVERALL UPPER LEVEL AND SURFACE FEATURES. ON
MONDAY...ETA WAS SLOWER WITH UPPER WAVE AND ASSOCIATED SURFACE FRONT
MOVING INTO OUR FORECAST AREA. OVERALL...PREFER THE ETA WITH RESPECT
TO DETAILS.

RAIN SHOULD BE DIMINISHING TONIGHT AS STRONGEST FORCING ASSOCIATED
WITH ISENTROPIC LIFT MOVES INTO GREAT LAKES. WINDY/BLUSTERY
CONDITIONS EXPECTED PER ETA SURFACE PRESSURE GRADIENT FIELD...BUT
SHOULD BE MARGINAL ENOUGH FOR WIND ADVISORY TO BE ALLOWED TO EXPIRE
AT 4 PM. SCATTERED SHOWERS COULD LINGER ON SUNDAY MAINLY FROM THE
MISSISSIPPI RIVER INTO CENTRAL WI. THIS ALREADY HANDLED WELL IN
CURRENT FORECAST. TIME/HEIGHT CROSS SECTIONS INDICATED ABUNDANT LOW
LEVEL MOISTURE REMAINS THROUGH SUNDAY. BASED ON EXPANSIVE CLOUD
SHIELD WESTWARD INTO THE DAKOTAS CURRENTLY ON SATELLITE...OPTED TO
CHANGE ALL ZONES TO INDICATE MORE CLOUDS SUNDAY.

ON MONDAY...SHORT WAVE DIVING SOUTHEAST TOWARD LAKE SUPERIOR...ALONG
WITH WEAK SURFACE FRONT PROGRESSING TOWARD THE FORECAST AREA. ETA
MODEL SHOWS DECENT WARM AIR ADVECTION...THETA-E CONVERGENCE AND CAPES
OF 500 J/KG TO INTRODUCE CHANCE PROBABILITIES OF RAIN IN NORTH
CENTRAL WI. TQ INDEX...WHICH ACCESSES LOW TOP CONVECTIVE POTENTIAL...
SUGGESTS A FEW THUNDERSTORMS POSSIBLE AS WELL IN NORTH CENTRAL WI.

DUE TO THE CLOUDS...MAXIMUM TEMPERATURES ON SUNDAY SHOULD BE MAINLY
IN THE 50S...THEN MOSTLY 60S FOR MONDAY AND TUESDAY WHEN SUNSHINE
RETURNS. FWC AND MAV GUIDANCE...AS WELL AS ETA 2M VALUES...SUPPORT
THIS. OF NOTE...ETA 2M TEMPERATURES SUGGEST SUNDAY NIGHT MINIMUMS
COULD DROP INTO THE UPPER 30S WEST OF THE MISSISSIPPI RIVER WHERE THE
CLOUDS SHOULD CLEAR OUT. THEREFORE...TRENDED TEMPERATURES DOWNWARD IN
SOUTHEAST MN AND NORTHEAST IOWA. READINGS IN THE MIDDLE TO UPPER
30S COULD OCCUR AREAWIDE MONDAY NIGHT AS SURFACE HIGH BUILDS IN...
SO TRENDED DOWNWARD IN ALL ZONES FROM CURRENT FORECAST.

IN THE LONGER TERM...MEDIUM RANGE MODELS HAVE DECENT CONTINUITY WITH
RESPECT TO A FRONT MOVING INTO THE UPPER MISSISSIPPI VALLEY DURING
THE MIDDLE TO LATTER PART OF THE WEEK. THIS SUPPORTS NEXT SHOWER
AND THUNDERSTORM CHANCES. IN ADDITION...TEMPERATURES SHOULD REACH
MORE SEASONAL LEVELS AS 500MB RIDGE BUILDS ACROSS THE REGION.

.LSE...NONE.

THOMPSON