Severe Thunderstorm Warning 51, NWS La Crosse, WI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
300 AM CDT MON MAY 6 2002

MAIN FORECAST FOCUS REMAINS ON RAIN CHANCES. TEMPERATURES ALSO
PROBLEMATIC WITH BOUNDARY IN THE AREA.

LATEST SURFACE ANALYSIS SHOWS FRONTAL BOUNDARY REACHING FROM
SOUTHEAST TIP OF SD ACROSS SOUTHERN MN AND INTO NORTHWEST WI.
GOOD DEAL OF CONVECTION FOUND ON REGIONAL RADAR MOSAICS SOUTHEAST
OF THIS BOUNDARY.

COMPARING MODELS WITH LATEST CONDITIONS LEAD ME TO FAVOR ETA MODEL
TODAY.

EXPECT SCATTERED SHOWERS AND THUNDERSTORMS TO MOVE THROUGH FAR
SOUTHERN ZONES THIS MORNING...AS CONVECTION OVER IA MOVES NORTHEAST
TOWARD WI.  WILL GO WITH CATEGORICAL WORDING THERE FOR THE MORNING.
ELSEWHERE...SATELLITE SHOWING SOME CLEARING FROM NE UP INTO SOUTHWEST
MN.  MODELS ALSO SHOW PATCHES OF DRY AIR AROUND...AND THE RESULTING
SUNSHINE SHOULD HELP TO DESTABILIZE THE LOWER ATMOSPHERE.  AS A
RESULT...DESPITE MODELS NOT PAINTING ANY QPF AND THE LOW POPS IN
ALL GUIDANCE...WILL MAINTAIN AT LEAST A 30 PERCENT CHANCE FOR NEW
DEVELOPMENT LATER TODAY.  TEMPERATURES WILL BE DEPENDANT ON WHERE
THE BOUNDARY ENDS UP.  MODELS ALL WANT TO SAG THE BOUNDARY SOUTH
THROUGH THE DAY.  THIS LIKELY TO HAPPEN...BUT TIMING OF THIS WILL
PLAY A BIG ROLE IN JUST HOW WARM WE CAN GET.  PLAN TO GO ABOVE
GUIDANCE MOST AREAS WITH LOWER ATMOSPHERE REMAINING QUITE MILD.

MORE OF THE SAME STORY FOR TONIGHT. MODELS NOT TOO KEEN ON RAIN
DEVELOPMENT.  HOWEVER...WE WILL BE CLOSE TO THE ACTION.  WILL
MAINTAIN LOW POPS TO BE ON THE SAVE SIDE.  MODELS LATCH ONTO ANOTHER
DISTURBANCE FOR TUESDAY.  SHOULD BE ANOTHER ROUND OF CONVECTION TO
DEAL WITH...AND 50 POPS LOOK GOOD.  BETTER CHANCES TUESDAY NIGHT
INTO WEDNESDAY AS THE LAST IN A SERIES OF DISTURBANCES ROTATES
THROUGH THE FLOW.

FINALLY...BY THURSDAY WE SEE THE PATTERN SHIFT ENOUGH THAT DRY HIGH
PRESSURE CAN SETTLE IN.  THURSDAY NIGHT AND FRIDAY LOOK RATHER NICE
AS WELL...BUT FRIDAY COULD BE A BIT BREEZY AS THE HIGH BEGINS TO
MOVE AWAY AND A TIGHT GRADIENT IS SET UP AS NEXT LEE LOW DEVELOPS.

.LSE...NONE.

MW

IAZ008>011-018-019-029-030-MNZ079-086>088-094>096-WIZ017-029-032>034-
041>044-053>055-061-062300-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LA CROSSE WI
100 PM CDT MON MAY 6 2002

HAZARD - SCATTERED THUNDERSTORMS.

TIMING - THIS AFTERNOON AND EVENING.

LOCATION - ALL OF NORTHEAST IOWA...SOUTHEAST MINNESOTA...AND
SOUTHWEST INTO CENTRAL WISCONSIN.

DISCUSSION - A NEARLY STATIONARY FRONT FROM NORTHEAST WISCONSIN INTO
NORTHWEST IOWA WILL MOVE VERY SLOWLY EAST TODAY. A MOIST...AND
WEAK TO MODERATELY UNSTABLE AIRMASS WILL REMAIN OVER THE AREA SOUTH
OF THE FRONT. THE FRONT...AND A WAVE OF LOW PRESSURE MOVING ALONG
IT...ARE EXPECTED TO TRIGGER SCATTERED SHOWERS AND THUNDERSTORMS
THIS AFTERNOON INTO THIS EVENING. ALONG WITH THE INSTABILITY...WIND
PROFILES SUPPORT THUNDERSTORM DEVELOPMENT. THERE IS A SLIGHT RISK
FOR SEVERE WEATHER SOUTH OF THE BOUNDARY...MAINLY ALONG AND SOUTH OF
A OSAGE IOWA TO TOMAH WISCONSIN LINE. THE MAIN SEVERE THREAT WOULD
BE LARGE HAIL.

SPOTTER INFORMATION - SPOTTER ACTIVATION COULD BECOME NECESSARY
LATER THIS AFTERNOON.

RIECK/RRS