Severe Thunderstorm Warning 164, NWS La Crosse, WI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
239 PM CDT TUE SEP 1997

IMMEDIATE FORECAST CONCERN IS FOR SEVERE WEATHER THREAT OVER THE
SOUTHERN HALF OF THE FORECAST AREA. TIMING THE ENDING OF THUNDERSTORMS
AND AMOUNT OF CLEARING IS A CHALLENGE FURTHER INTO THE NIGHT.

MID AFTERNOON SURFACE ANALYSIS HAD AN OCCLUDED/COLD FRONT COMBO RUNNING
FROM NC-SW MN AND THEN INTO WRN IA. ANOTHER CONVERGENT AXIS WAS NEAR
DSM. SOUTHERLY FLOW WAS ADVECTION WARM/MOIST AIR PARCELS NWD INTO IA
AND SRN MN AND THEN OVERTOP A MESO-WARM FRONT LINED UP THROUGH MSP-GRB.
THE RESULT HAS BEEN WIDESPREAD OVERRUNNING CONVECTION OVER THE NRN HALF
OF THE FORECAST AREA. CONVECTION WAS NOW BEGINNING TO TAKE SHAPE OVER
MUCH OF WRN IA AS MID LEVEL CAP WAS BREAKING. STORMS ARE EXPECTED TO
EXPAND AND INTENSIFY INTO SC MN LATE THIS AFTERNOON. AS THE STORMS
TRAVERSE EWD THEY WILL ENCOUNTER 1500-2000 J/KG CAPES AND PLENTY OF
JUICE. MAIN THREAT WILL BE DAMAGING WINDS GIVEN WIND FLOW ALOFT. BEST
SEVERE WEATHER POTENTIAL STILL APPEARS TO BE OVER THE SOUTHERN HALF OF
IA.

ONLY ONE MODEL TO CHOOSE FROM TODAY...THE NGM...AND IT APPEARS TO BE
REASONABLE.  COLD FRONT WILL MOVE TO ERN WI-ERN IA BY 06Z TONIGHT. BAND
OF STRONG-SEVERE THUNDERSTORMS WILL BEGIN TO END IN SE MN/NE IA THIS
EVENING AND IN WRN/CNTRL WI AROUND MIDNIGHT.  SOME CONCERN ON THE
AMOUNT OF CLEARING LATE TONIGHT.  NGM TENDS TO CLEAR US OUT
ABRUPTLY...BUT WOULD BE MORE COMFORTABLE WITH A GRADUAL CLEARING VERY
LATE TONIGHT GIVEN THE MID/UPPER LEVEL MOISTURE SEEN ON SATELLITE BACK
INTO THE ERN DKTS.

NGM MOS MAY BE TOO COOL WITH MORE CLOUDINESS EXPECTED...BUT
TEMPERATURES WILL DEFINATELY BE COOLER THAN THE PAST FEW NIGHT.

RACY

IAZ008>011-018-019-029-030-MNZ079-086>088-094>096-WIZ017-029-
032>034-041>044-053>055-061-170000-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LA CROSSE WI
135 PM CDT TUE SEP 16 1997

...STRONG THUNDERSTORMS ARE STILL EXPECTED THROUGH THE REMAINDER OF THE
AFTERNOON...

THERE CONTINUES TO BE A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER
WESTERN AND CENTRAL WISCONSIN...SOUTHEAST MINNESOTA AND NORTHEAST IOWA
THIS AFTERNOON. HOWEVER...LATEST INDICATIONS ARE THAT THE BEST THREAT
OF SEVERE WEATHER WILL BE JUST SOUTH OF THE AREA.

AT EARLY AFTERNOON...A FAIRLY EXPANSIVE AREA OF SHOWERS AND
THUNDERSTORMS COVERED THE UPPER MISSISSIPPI RIVER VALLEY. SOME OF THE
STORMS HAD PRODUCED SMALL HAIL AND WIND GUSTS UP TO 40 MPH. THE STORMS
WERE MOVING NORTHEAST.

A COLD FRONT WAS PLOWING THROUGH WESTERN MINNESOTA AND IOWA AT MIDDAY.
OUT AHEAD OF THE FRONT...SOME SUNSHINE HAS BEEN NOTED OVER MUCH OF IOWA
AND THE AIR WAS BECOMING INCREASINGLY UNSTABLE.  THUNDERSTORMS ARE
EXPECTED TO REFORM OVER WESTERN IOWA DURING THE MID AFTERNOON...THEN
TRANSLATE EAST WITH THE COLD FRONT.  IT NOW APPEARS THE BEST THREAT OF
SEVERE WEATHER WILL OCCUR OVER CENTRAL AND SOUTHERN PORTIONS OF IOWA.
HOWEVER...ISOLATED SEVERE THUNDERSTORMS WITH DAMAGING WINDS ARE
POSSIBLE OVER THE REST OF THE AREA...MAINLY FROM ROCHESTER-LA
CROSSE-WISCONSIN DELLS SOUTH.

EMERGENCY MANAGERS AND SPOTTER GROUPS MAY BE ACTIVATED LATER THIS
AFTERNOON.

RACY

IAZ008>011-018-019-029-030-MNZ079-086>088-094>096-WIZ041-042-
053-054-162220-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
345 PM CDT TUE SEP 16 1997

...A SEVERE THUNDERSTORM WATCH CONTINUES IN EFFECT UNTIL 8PM FOR
MOST OF SOUTHEAST MINNESOTA...NORTHEAST IOWA...AND A SMALL PART OF
SOUTHWEST WISCONSIN...

THE SEVERE THUNDERSTORM WATCH INCLUDES THE TOWNS OF
ROCHESTER...AUSTIN...SPRING VALLEY...WINONA MINNESOTA...CHARLES
CITY...NEW HAMPTON...DECORAH...OSAGE...WAUKON AND FAYETTE IOWA AND
LA CROSSE...VIROQUA...MT. STERLING AND SPARTA WISCONSIN.

AT MID AFTERNOON...A LARGE BATCH OF SHOWERS AND THUNDERSTORMS
COVERED WESTERN WISCONSIN BACK INTO SOUTHEAST MINNESOTA AND
NORTHEAST IOWA. THE STRONGEST THUNDERSTORMS WERE PRODUCING
TORRENTIAL RAINS AND WIND GUSTS UP TO 40 MPH...BUT NONE WERE SEVERE.

STRONGER THUNDERSTORMS WERE BEGINNING TO FORM OVER CENTRAL IOWA AND
WERE TRACKING NORTHEAST TOWARD THE WATCH AREA.  THE STORMS WILL
APPROACH NORTHEAST IOWA BY 5PM.  DAMAGING WINDS WILL BE THE MAIN
THREAT FROM THESE STORMS.

A COLD FRONT WAS MOVING INTO CENTRAL MINNESOTA AND CENTRAL IOWA.
THE AIR OUT AHEAD OF THE FRONT WAS UNSTABLE. THE BEST THREAT FOR
SEVERE WEATHER APPEARS TO BE DOWN OVER SOUTHEAST IOWA.

STAY TUNED TO YOUR FAVORITE WEATHER SOURCE FOR LATER INFORMATION.

RACY

IAZ011-030-WIZ053>055-061-162325-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
519 PM CDT TUE SEP 16 1997

...A LINE OF STRONG OF THUNDERSTORMS WAS POISED TO MOVE ACROSS
SOUTHWEST WISCONSIN AND FAR EASTERN PARTS OF NORTHEAST IOWA...

AT 515 PM...DOPPLER RADAR SHOWED A LINE OF STRONG THUNDERSTORMS
EXTENDING FROM DECORAH TO 40 MILES NORTHWEST OF DUBUQUE.  THE
STORMS WERE MOVING NORTHEAST AT 40 MPH AND CONTAINED WIND GUSTS UP
TO 45 MPH...PEA SIZED HAIL AND TORRENTIAL RAINS.

THE STORMS WILL IMPACT WAUKON AND CLAYTON BY 530 PM...AND
VIROQUA...MT.STERLING...AND LANCASTER BETWEEN 545 AND 6PM.
THE STORMS WILL LAST ABOUT A HALF HOUR...WITH LIGHT TO MODERATE
SHOWERS CONTINUING INTO EARLY EVENING BEHIND THE MAIN BAND.

STAY TUNED TO YOUR FAVORITE WEATHER SOURCE FOR LATER STATEMENTS.

RACY

IAZ011-030-WIZ053>055-061-162325-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
519 PM CDT TUE SEP 16 1997

...A LINE OF STRONG OF THUNDERSTORMS WAS POISED TO MOVE ACROSS
SOUTHWEST WISCONSIN AND FAR EASTERN PARTS OF NORTHEAST IOWA...

AT 515 PM...DOPPLER RADAR SHOWED A LINE OF STRONG THUNDERSTORMS
EXTENDING FROM DECORAH TO 40 MILES NORTHWEST OF DUBUQUE.  THE
STORMS WERE MOVING NORTHEAST AT 40 MPH AND CONTAINED WIND GUSTS UP
TO 45 MPH...PEA SIZED HAIL AND TORRENTIAL RAINS.

THE STORMS WILL IMPACT WAUKON AND CLAYTON BY 530 PM...AND
VIROQUA...MT.STERLING...AND LANCASTER BETWEEN 545 AND 6PM.
THE STORMS WILL LAST ABOUT A HALF HOUR...WITH LIGHT TO MODERATE
SHOWERS CONTINUING HINTO EARLY EVENING BEHIND THE MAIN BAND.

STAY TUNED TO YOUR FAVORITE WEATHER SOURCE FOR LATER STATEMENTS.

RACY

IAZ008>011-018-019-029-030-MNZ086>088-094>096-170010-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
606 PM CDT TUE SEP 16 1997

...SEVERE THUNDERSTORM WATCH HAS BEEN CANCELLED EARLY FOR SOUTHEAST
MINNESOTA AND NORTHEAST IOWA...

SEVERE THUNDERSTORM WATCH NUMBER 729 HAS BEEN CANCELLED FOR THE
FOLLOWING COUNTIES...

IN IOWA...MITCHELL - FLOYD - HOWARD - CHICKASAW - WINNESHIEK -
FAYETTE - ALLAMAKEE - CLAYTON.

IN SOUTHEAST MINNESOTA...DODGE - OLMSTED - WINONA - MOWER -
FILLMORE - HOUSTON.

THE STORMS HAVE MOVED THROUGH OR JUST SOUTH OF THE AREA. SCATTERED
SHOWERS AND THUNDERTORMS WILL CONTINUE OVER THE AREA THROUGH EARLY
EVENING...BUT NO SEVERE WEATHER IS ANTICIPATED IN THE CANCELLED
WATCH AREA.

THE WATCH REMAINS IN EFFECT FOR A SMALL PART OF SOUTHWEST WISCONSIN
UNTIL 8PM.

RACY

IAZ008>011-018-019-029-030-MNZ086>088-094>096-170010-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
606 PM CDT TUE SEP 16 1997

...SEVERE THUNDERSTORM WATCH HAS BEEN CANCELLED EARLY FOR SOUTHEAST
MINNESOTA AND NORTHEAST IOWA...

SEVERE THUNDERSTORM WATCH NUMBER 729 HAS BEEN CANCELLED FOR THE
FOLLOWING COUNTIES...

IN IOWA...MITCHELL - FLOYD - HOWARD - CHICKASAW - WINNESHIEK -
FAYETTE - ALLAMAKEE - CLAYTON.

IN SOUTHEAST MINNESOTA...DODGE - OLMSTED - WINONA - MOWER -
FILLMORE - HOUSTON.

THE STORMS HAVE MOVED THROUGH OR JUST SOUTH OF THE AREA. SCATTERED
SHOWERS AND THUNDERTORMS WILL CONTINUE OVER THE AREA THROUGH EARLY
EVENING...BUT NO SEVERE WEATHER IS ANTICIPATED IN THE CANCELLED
WATCH AREA.

THE WATCH REMAINS IN EFFECT FOR A SMALL PART OF SOUTHWEST WISCONSIN
UNTIL 8PM.

RACY