Severe Thunderstorm Warning 123, NWS La Crosse, WI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
255 PM CDT MON JUL 30 2001

MAIN FORECAST CONCERNS ARE THE HEAT AND HUMIDITY FOR THE NEXT COUPLE
DAYS...ONGOING PCPN...AND THE CHANCE FOR SOME RELIEF WIDESPREAD
RELIEF ON WEDNESDAY.

THE 17Z SURFACE ANALYSIS PLACED A LOW OVER CENTRAL SD...WITH A WARM
FRONT EXTENDING FROM THE LOW INTO NORTHCENTRAL WI...THEN TURNING
SOUTHEAST INTO SOUTHERN LAKE MICHIGAN. LATEST 88-D IMAGERY INDICATED
SCATTERED SHOWERS AND THUNDERSTORMS OVER NORTHERN WI...NORTH OR
ALONG THE WARM FRONT.

12Z MODEL INITIALIZATIONS LOOK GOOD WITH NOTHING GLARING. SOLUTIONS
ALSO REASONABLY CONSISTENT AND PRETTY CLOSE...EXCEPT...AGAIN...IN
THE QPF FIELDS. ALTHOUGH THE MODELS HAVE HAD SOME DIFFICULTLY
PICKING UP ALL THE CONVECTION OVER THE LAST COUPLE DAYS...FEEL THE
ETA HAS DONE THE BETTER JOB OVERALL...AND WILL USE IT FOR FORECAST
DETAILS.

IN THE IMMEDIATE TERM...SHOWERS/STORMS CONTINUE TO ADVANCE TO THE
SOUTH...MOVING INTO SOME FAVORABLY SURFACE BASED MOISTURE
CONVERGENCE AND A BAROLCLINIC ZONE. THE BEST SUPPORT FOR THESE
STORMS LOOKS TO BE OVER WESTERN WI CURRENTLY...BUT WILL SHIFT TO THW
WEST TONIGHT. WILL ADD MENTION TO PORTIONS OF THE AREA FOR THIS
EVENING AS A RESULT.

THE UPPER LEVEL RIDGE AXIS WILL BE CENTERED NORTH-SOUTH ACROSS WI BY
12Z TUE...MOVING EAST AND ACQUIRING A POSITIVE TILT BY WED
AFTERNOON. THE AXIS WILL THEN TILT FROM NORTHEAST MICH INTO THE
SOUTHERN PLAINS. THIS IS IN RESPONSE TO A SHORTWAVE THAT MOVED ONTO
THE PAC COAST THIS MORNING...AND WILL SPIN EAST NORTHEAST ACROSS THE
NORTHERN PLAINS LATE TUESDAY NIGHT. THE RIDGE WILL SERVE TO INHIBIT
CONVECTION ACROSS THE FORECAST AREA ON TUESDAY THROUGH TUESDAY
EVENING...BEFORE FINALLY GIVING AWAY TO THE COLD FRONT ON WEDNESDAY.

TONIGHT...LOW LEVEL JET AND MOISTURE TRANSPORT POINT TO MCS
DEVELOPMENT OVER ND. ETA QPF DOES PAINT SOME PCPN OVER IOWA...WHICH
LOOKS TO BE IN RESPONSE TO 850 THETA-E ADVECTION AND DEWPOINT
GRADIENT...ALONG WITH SOME SURFACE MOISTURE CONVERGENCE. MODELS DO
NOT ACCOUNT FOR THE ONGOING PCPN...KEEPING THE BETTER FORCING TO THE
WEST. AS MENTIONED ABOVE...BASED ON THE CURRENT PCPN AND AVAILABLE
FORCING...WILL ADD PCPN MENTION FOR THIS EVENING ACROSS PORTIONS OF
THE AREA...MOSTLY NORTH AND WEST. FOR THE MCS...CORFIDI VECTORS
WOULD MOVE IT MOSTLY NORTHEAST...ON THE EDGE OF THE CAP AND ALONG
AND NORTH OF THE SURFACE BOUNDARY (WHICH SHOULD RUN FROM A LOW OVER
WESTERN SD INTO NORTHERN MN TONIGHT). FOR TUESDAY...A VERY SIMILAR
DAY TO TODAY...BUT LIKELY A COUPLE DEGREES WARMER AND A BIT MORE
HUMID. TYPICAL SUMMER WEATHER...IF YOU LIVE IN THE AMAZON. THIS
COMBINATION OF HIGHS 90 OR GREATER AND DEWPOINTS 70 OR GREATER WILL
CREATE HEAT INDICES FROM 100 TO 105 DEGREES. THIS IS GETTING CLOSE
TO A HEAT ADVISORY...BUT A BIT BELOW CRITERIA...SO WILL NOT ISSUE
ONE BUT KEEP HEAT INDICES MENTIONED IN THE FORECAST.

TUESDAY NIGHT...THE ACTIVITY WILL STAY ALONG THE COLD FRONT...WITH
THE LOW LEVEL MOISTURE RETURN AND JET PUNCHING INTO THIS BOUNDARY.
AGAIN...THIS SHOULD KEEP MOST OF THE AREA DRY...WITH PCPN INCREASING
TOWARD WED MORNING...ESPECIALLY TO THE WEST. WEDNESDAY LOOKS LIKE A
PRETTY GOOD CHANCE FOR SOME WETTING...WITH THE FRONT SLIDING ACROSS
THE AREA DURING THE DAY. TEMPERATURES WILL PROBABLY BE TEMPERED A
BIT FOR WEDNESDAY...DEPENDING ON THE CLOUD COVER AHEAD OF THE
FRONT...AND THE TIME IS PASSES THROUGH. REGARDLESS...TEMPERATURES
WILL RETURN TO MORE SEASONABLE READINGS FOR THURSDAY...ALONG WITH
LESS HUMID CONDITIONS.

COORDINATED WITH DMX.

.LSE...NONE.

RIECK

IAZ008>011-018-019-029-030-MNZ079-086>088-094>096-WIZ017-029-032>034-
041>044-053>055-061-310500-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LA CROSSE WI
1205 PM CDT MON JUL 30 2001

HAZARD - SCATTERED THUNDERSTORMS.

TIMING - EARLY THIS AFTERNOON AND AGAIN LATE TONIGHT.

LOCATION - EARLY THIS AFTERNOON CLARK/TAYLOR COUNTIES.
           TONIGHT MUCH OF SOUTHEAST MINNESOTA AND NORTHEAST IOWA.

DISCUSSION - A COMPLEX OF THUNDERSTORMS OVER NORTHERN WISCONSIN IS
EXPECTED TO SLOWLY WEAKEN AS THEY TRACK SOUTHEAST THROUGH EARLY
AFTERNOON...AFFECTING MAINLY CLARK AND TAYLOR COUNTIES. MAIN THREAT
WILL BE HAIL AND GUSTY WINDS.

THE FLOW OF WARM...MOIST...AND UNSTABLE AIR INTO THE AREA WILL
CONTINUE TONIGHT. THUNDERSTORMS ARE EXPECTED ALONG A TROUGH IN
EASTERN SOUTH DAKOTA AND FAR WESTERN MINNESOTA THIS AFTERNOON...THEN
MOVE EAST TONIGHT AND REACH SOUTHEAST MINNESOTA AND NORTHEAST IOWA
LATER TONIGHT. THE STORMS ARE EXPECTED TO WEAKEN AS THEY MOVE EAST
INTO LESS WIND SHEAR. THIS...PLUS THE LATE NIGHT TIMING...IS EXPECTED
TO KEEP ANY STORMS THAT MOVE IN BELOW SEVERE LIMITS.

SPOTTER INFORMATION - SPOTTER ACTIVATION IS NOT ANTICIPATED AT THIS
TIME.

RABERDING