Severe Thunderstorm Warning 140, NWS La Crosse, WI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
310 AM CDT FRI SEP 1 2000

MAIN FORECAST CONCERN FOR THIS PACKAGE IS ON FRONTAL POSITION. AS
THIS WILL HAVE BIG IMPACT ON TEMPERATURES...PRECIPITATION AND CLOUD
COVER.

06Z SURFACE ANALYSIS SHOWS COLD FRONT EXTENDING FROM JUST SOUTH OF
KGRB...TO NEAR KPDC...AND INTO CENTRAL IOWA. DEWPOINTS IN THE 70S
COMMON TO THE SOUTH OF THIS BOUNDARY AND FALL OFF INTO THE LOWER
50S ACROSS CENTRAL MINNESOTA. CONVECTION ACROSS NORTHERN ZONES HAS
MOVED OFF TO THE EAST. FOG PRODUCT SATELLITE IMAGERY SHOWS
EXTENSIVE AREA OF LOW CLOUDS BEHIND FRONT EXPANDING SOUTHWARD.

00Z MODELS IN GOOD AGREEMENT WITH THE MASS FIELDS...BUT DIFFER WITH
QPF. ETA APPEARS TO BE VERIFYING BEST AT 06Z.

UPPER LOW TO CONTINUE TO SPIN OFF THE NORTHWEST U.S COAST WITH
BROAD TROUGH ACROSS ALL OF THE WESTERN CONUS. MEANWHILE RIDGING WILL
CONTINUE FROM THE MID SECTION OF THE COUNTRY EASTWARD. UPPER FLOW
OVER FORECAST AREA TO REMAIN SOUTHWEST...PARALLEL TO THE FRONTAL
BOUNDARY. THUS BOUNDARY NOT PROGGED TO MOVE MUCH NEXT SEVERAL DAYS.
EXPECT BOUNDARY TO END UP EXTENDING FROM CENTRAL IOWA...INTO
NORTHERN ILLINOIS BY THIS AFTERNOON. SHORTWAVE IS EXPECTED TO MOVE
ACROSS AREA THIS AFTERNOON/EVENING OVERRIDING THIS BOUNDARY. TIMING
LOOKS TO BE AT PEAK HEATING...THUS CHANCE POPS LOOK GOOD ALONG AND
JUST TO THE NORTH OF THE BOUNDARY.

NEXT SYSTEM TO GET ORGANIZED OVER THE PLAINS ON SATURDAY WITH
BOUNDARY RETURNING NORTH AS A WARM FRONT. THUS WITH BOUNDARY STILL
IN THE AREA WILL CONTINUE CHANCE POPS FOR SATURDAY...IN LINE WITH
PREVIOUS FORECAST.

TEMPERATURES RATHER TRICKY GIVEN AMOUNT OF CLOUD COVER AND BOUNDARY
IN VICINITY. THE COOLER AND DRIER AIR IS LAGGING BEHIND FRONT SOME
40 TO 60 MILES. WITH THIS IN MIND WILL TAPER TEMPERATURES FROM THE
MIDDLE 80S NORTHEAST IOWA...TO MIDDLE 70S CLARK/TAYLOR COUNTIES
TODAY. AS BOUNDARY RETURNS NORTH AS WARM FRONT SATURDAY
TEMPERATURES RETURN TO THE 80S IN MOST AREAS. GUIDANCE NUMBERS IN
GOOD AGREEMENT THROUGH 48 HOURS...ALTHOUGH FAN TEMPERATURES APPEAR
TO BE TOO LOW ACROSS THE SOUTHERN CUTS FOR SATURDAY.

.LSE...NONE.

RABERDING

IAZ008>011-018-019-029-030-MNZ079-086>088-094>096-WIZ017-029-032>034-
041>044-053>055-061-020000-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LA CROSSE WI
1213PM CDT FRI SEP 1 2000

...A SLIGHT CHANCE OF SEVERE THUNDERSTORMS THIS AFTERNOON...

A FRONTAL BOUNDARY WILL WAVER ACROSS SOUTHERN WISCONSIN AND NORTHERN
IOWA THIS AFTERNOON AND THEN MOVE SLOWLY SOUTHEAST LATER TONIGHT. AT
THE SAME TIME...A SERIES OF UPPER LEVEL DISTURBANCES WILL MOVE ACROSS
THE AREA. THESE TWO WEATHER FEATURES WILL SERVE AS THE FOCUS FOR
THUNDERSTORM DEVELOPMENT THIS AFTERNOON AND TONIGHT. A FEW OF THESE
THUNDERSTORMS MAY BECOME SEVERE THIS AFTERNOON. THE PRIMARY THREAT WILL
BE LARGE HAIL AND DAMAGING WINDS.

EMERGENCY MANAGERS AND SPOTTERS SHOULD CONTINUE TO MONITOR NOAA
WEATHER RADIO OR THEIR FAVORITE WEATHER SOURCE FOR FURTHER UPDATES
ON THIS POTENTIAL WEATHER SITUATION.

BOYNE