Severe Thunderstorm Warning 107, NWS La Crosse, WI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
200 PM CDT WED JUL 16 1997

THUNDERSTORMS ARE THE MAIN CONCERN OF THE NIGHT.

AT 17Z...VISIBLE SATELLITE IMAGERY SHOWED AREAS OF CLOUDS OVER PORTIONS
OF THE DAKOTAS...NORTHERN MINNESOTA AND NORTHERN WISCONSIN...SEVERAL
BOUNDARIES CAN ALSO BE SEEN JUST OUTSIDE OF THE FORECAST AREA IN THE
CLOUD FIELD. DEWPOINTS ACROSS THE FORECAST AREA RANGE FROM 70 IN CENTRAL
WISCONSIN TO THE MIDDLE 70S ACROSS SOUTHEAST MINNESOTA AND NORTHEAST
IOWA. LATEST SURFACE OBSERVATIONS THE MAIN SURFACE TROUGH EXTENDING
FROM NORTHEAST NORTH DAKOTA INTO SOUTH CENTRAL SOUTH DAKOTA. ANOTHER
SURFACE TROUGH APPARENTLY BEING INDUCED BY AN UPPER LEVEL WAVE EXTENDS
FROM NORTHEAST MINNESOTA TO SOUTHWEST MINNESOTA AND WAS MOVING TO THE
EAST.

12Z ETA/NGM FORECAST SOUNDINGS MODIFIED FOR THE ACTUAL LOW LEVEL
DEWPOINTS YIELD CAPES IN THE 5000 TO 6500 J/KG RANGE ACROSS THE
FORECAST AREA TONIGHT. ETA HELICITY VALUES GENERALLY IN THE 100 TO 180
RANGE DURING THE NIGHT WITH THE GREATEST SHEAR IN NORTHERN SECTIONS OF
THE FORECAST AREA.  ETA HAS STRONG DIVERGENCE AT 250 MB AT 06Z OVER
SOUTHEAST MINNESOTA BUT APPEARS TO BE CONVECTIVELY INDUCED.

WITH AMPLE AVAILABLE ENERGY AND SOME BOUNDARIES TO FOCUS ON NORTH OF
THE FORECAST AREA EXPECT THUNDERSTORMS TO CONTINUE TO DEVELOP AND
ORGANAIZE.  NORTHWESTERLY FLOW ALOFT SHOULD MOVE CONVECTIVE ACTIVITY
INTO THE FORECAST AREA DURING THE EVENING AND EXPECT SOME STORMS TO
BECOME SEVERE.  FREEZING LEVELS ARE HIGH AT 14500 FEET BUT WITH THE
VERY UNSTABLE AIR EXPECT SOME HAIL IN THESE STORMS ALONG WITH DAMAGING
WINDS IN THE NORTHERN HALF OF THE AREA.

NELSON

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
1120 AM CDT WED JUL 16 1997

...MODERATE RISK FOR SEVERE THUNDERSTORMS IN PORTIONS OF SOUTHEAST
MINNESOTA AND WESTERN WISCONSIN...

FOR TONIGHT...THE STORM PREDICTION CENTER HAS INDICATED THERE IS A
MODERATE RISK OF SEVERE THUNDERSTORMS GENERALLY NORTH OF A LINE FROM
CAMP DOUGLAS WISCONSIN TO LA CROSSE TO MANKATO MINNESOTA AND WEST OF A
LINE FROM CAMP DOUGLAS TO CHIPPEWA FALLS WISCONSIN. THERE IS ALSO A
SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE REST OF SOUTHEAST
MINNESOTA AND WEST CENTRAL WISCONSIN.

THE MAIN SEVERE WEATHER THREATS WILL BE DAMAGING WINDS AND LARGE HAIL.
THE STORMS ARE EXPECTED TO INITIALLY DEVELOP ALONG A LOW PRESSURE
TROUGH IN THE EASTERN DAKOTAS...AND THEN MOVE SOUTHEAST REACHING
SOUTHEAST MINNESOTA LATE THIS EVENING AND CONTINUING INTO WESTERN
WISCONSIN.

SPOTTER ACTIVATION MAY BE NECESSARY BY LATE THIS EVENING ESPECIALLY IN
SOUTHEAST MINNESOTA AND WESTERN WISCONSIN.

NELSON

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
1120 AM CDT WED JUL 16 1997

...MODERATE RISK FOR SEVERE THUNDERSTORMS IN PORTIONS OF SOUTHEAST
MINNESOTA AND WESTERN WISCONSIN...

FOR TONIGHT...THE STORM PREDICTION CENTER HAS INDICATED THERE IS A
MODERATE RISK OF SEVERE THUNDERSTORMS GENERALLY NORTH OF A LINE FROM
CAMP DOUGLAS WISCONSIN TO LA CROSSE TO MANKATO MINNESOTA AND WEST OF A
LINE FROM CAMP DOUGLAS TO CHIPPEWA FALLS WISCONSIN. THERE IS ALSO A
SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE REST OF SOUTHEAST
MINNESOTA AND WEST CENTRAL WISCONSIN.

THE MAIN SEVERE WEATHER THREATS WILL BE DAMAGING WINDS AND LARGE HAIL.
THE STORMS ARE EXPECTED TO INITIALLY DEVELOP ALONG A LOW PRESSURE
TROUGH IN THE EASTERN DAKOTAS...AND THEN MOVE SOUTHEAST REACHING
SOUTHEAST MINNESOTA LATE THIS EVENING AND CONTINUING INTO WESTERN
WISCnONSIN.

SPOTTER ACTIVATION MAY BE NECESSARY BY LATE THIS EVENING ESPECIALLY IN
SOUTHEAST MINNESOTA AND WESTERN WISCONSIN.

NELSON

MNZ079-086>088-094>096-WIZ017-029-032>034-041>044-053>055-
061-170100-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LA CROSSE WI
154 PM CDT WED JUL 16 1997

...A MODERATE RISK OF SEVERE THUNDERSTORMS IN PORTIONS OF THE
AREA...

THE MODERATE RISK AREA IS GENERALLY NORTH OF A CAMP DOUGLAS-LA
CROSSE-MANKATO LINE AND WEST OF A CAMP DOUGLAS-CHIPPEWA
FALLS LINE. THERE IS A SLIGHT RISK OF SEVERE WEATHER OVER THE
REMAINDER OF WESTERN CENTRAL WISCONSIN AND SOUTHEAST MINNESOTA.

THUNDERSTORMS ARE EXPECTED TO FORM LATE THIS AFTERNOON OVER NORTH
CENTRAL WISCONSIN...THEN SPREAD SOUTH OVERNIGHT. THAT MEANS AREAS
AROUND MEDFORD AND NEILSVILLE HAVE THE THREAT OF SEVERE WEATHER
AFTER 3PM. ROCHESTER...LA CROSSE...BLACK RIVER FALLS AND FRIENDSHIP
WILL SEE THE SEVERE WEATHER THREAT INCREASE THIS EVENING INTO
OVERNIGHT. THE MAIN THREAT APPEARS TO BE HAIL UP TO THE SIZE OF GOLF
BALLS AND WIND GUSTS TO 70 MPH.

VERY UNSTABLE AIR RESIDED OVER THE AREA THIS AFTERNOON.  AN UPPER
AIR DISTURBANCE AND A WIND SHIFT AT THE SURFACE WILL MOVE EAST
AND HELP TRIGGER THUNDERSTORMS THROUGH THE OVERNIGHT.

EMERGENCY MANAGERS AND STORM SPOTTER GROUPS SHOULD KEEP ABREAST OF
THE WEATHER SITUATION AS THEY MAY NEED TO ACTIVATED.

RACY

MNZ079-086>088-094>096-WIZ017-029-032>034-041>044-053>055-
061-170100-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LA CROSSE WI
154 PM CDT WED JUL 16 1997

...A MODERATE RISK OF SEVERE THUNDERSTORMS IN PORTIONS OF THE
AREA...

THE MODERATE RISK AREA IS GENERALLY NORTH OF A CAMP DOUGLAS-LA
CROSSE-MANKATO LINE AND WEST OF A CAMP DOUGLAS-CHIPPEWA
FALLS LINE. THERE IS A SLIGHT RISK OF SEVERE WEATHER OVER THE
REMAINDER OF WESTERN CENTRAL WISCONSIN AND SOUTHEAST MINNESOTA.

THUNDERSTORMS ARE EXPECTED TO FORM LATE THIS AFTERNOON OVER NORTH
CENTRAL WISCONSIN...THEN SPREAD SOUTH OVERNIGHT. THAT MEANS AREAS
AROUND MEDFORD AND NEILSVILLE HAVE THE THREAT OF SEVERE WEATHER
AFTER 3PM. ROCHESTER...LA CROSSE...BLACK RIVER FALLS AND FRIENDSHIP
WILL SEE THE SEVERE WEATHER THREAT INCREASE THIS EVENING INTO
OVERNIGHT. THE MAIN THREAT APPEARS TO BE HAIL UP TO THE SIZE OF GOLF
BALLS AND WIND GUSTS TO 70 MPH.

VERY UNSTABLE AIR RESIDED OVER THE AREA THIS AFTERNOON.  AN UPPER
AIR DISTURBANCE AND A WIND SHIFT AT THE SURFACE WILL MOVE EAST
AND HELP TRIGGER THUNDERSTORMS THROUGH THE OVERNIGHT.

EMERGENCY MANAGERS AND STORM SPOTTER GROUPS SHOULD KEEP ABREAST OF
THE WEATHER SITUATION AS THEY 0MAY NEED TO ACTIVATED.

RACY

MNZ079-086>088-094>096-WIZ017-029-032>034-041>044-053>055-
061-IAZ008>011-018-019-029-030-170100-

HAZARDOUS WEATHER OUTLOOK...CORRECTED
NATIONAL WEATHER SERVICE LA CROSSE WI
235 PM CDT WED JUL 16 1997

...A MODERATE RISK OF SEVERE THUNDERSTORMS IN PORTIONS OF THE
AREA...

THE MODERATE RISK AREA IS GENERALLY NORTH OF A CAMP DOUGLAS-LA
CROSSE-MANKATO LINE. THERE IS A SLIGHT RISK OF SEVERE WEATHER OVER THE
REMAINDER OF WESTERN WISCONSIN...SOUTHEAST MINNESOTA AND NORTHEAST
IOWA.

THUNDERSTORMS ARE EXPECTED TO FORM LATE THIS AFTERNOON OVER NORTH
CENTRAL WISCONSIN...THEN SPREAD SOUTH OVERNIGHT. THAT MEANS AREAS
AROUND MEDFORD AND NEILSVILLE HAVE THE THREAT OF SEVERE WEATHER
AFTER 3PM. ROCHESTER...LA CROSSE...BLACK RIVER
FALLS...FRIENDSHIP...CHARLES CITY...LANCASTER WILL SEE THE SEVERE
WEATHER THREAT INCREASE THIS EVENING INTO OVERNIGHT. THE MAIN THREAT
APPEARS TO BE HAIL UP TO THE SIZE OF GOLF BALLS AND WIND GUSTS TO 70
MPH.

VERY UNSTABLE AIR RESIDED OVER THE AREA THIS AFTERNOON.  AN UPPER
AIR DISTURBANCE AND A WIND SHIFT AT THE SURFACE WILL MOVE EAST
AND HELP TRIGGER THUNDERSTORMS THROUGH THE OVERNIGHT.

EMERGENCY MANAGERS AND STORM SPOTTER GROUPS SHOULD KEEP ABREAST OF
THE WEATHER SITUATION AS THEY MAY NEED TO ACTIVATED.

RACY

CORRECTED TO ADD SLIGHT RISK FURTHER SOUTH