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URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 291

NWS STORM PREDICTION CENTER NORMAN OK

140 PM CDT THU MAY 12 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       SOUTHERN AND CENTRAL WISCONSIN



EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 140 PM UNTIL

700 PM CDT.



HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70

MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 80

STATUTE MILES EAST AND WEST OF A LINE FROM 5 MILES NORTH OF

RHINELANDER WISCONSIN TO 20 MILES WEST OF JANESVILLE WISCONSIN.

FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU1).



REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE

FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH

AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR

THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS

AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY

DO PRODUCE TORNADOES.



OTHER WATCH INFORMATION...CONTINUE...WW 288...WW 289...WW 290...



DISCUSSION...STRONG SURFACE HEATING AND MOIST AIR MASS ARE

CONTRIBUTING TO MLCAPE OF 1000 TO 2000 J PER KG ACROSS SRN AND

CENTRAL WI THIS AFTERNOON. CONTINUED HEATING SHOULD EFFECTIVELY

ELIMINATE REMAINING INHIBITION AND LEAD TO STORM INITIATION SHORTLY.

OVERALL STORM PERSISTENCE/ORGANIZATION MAY BE SOMEWHAT LIMITED BY

LACK OF GREATER FLOW/SHEAR ACROSS THE REGION. HOWEVER...WEAK MCV AND

ASSOCIATED FRONTAL LOW/WAVE MOVING ALONG WELL DEFINED

QUASI-STATIONARY FRONTAL BOUNDARY FROM NERN IA TO NCNTRL WI...IN

ADDITION TO LAKE-BREEZE REINFORCED BOUNDARY ACROSS ERN WI...MAY LEND

LOCAL/FOCUSED SUPPORT FOR BOTH STORM INITIATION AND UPDRAFTS

PERSISTENCE. SCATTERED SEVERE HAIL AND W FEW DAMAGING WIND EVENTS

AREA EXPECTED FROM PRIMARILY MULTICELLULAR STORMS DEVELOPING WITHIN

AN INCREASINGLY WARM AND UNSTABLE AIR MASS THROUGH LATE AFTERNOON.



AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT

TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 450. MEAN STORM

MOTION VECTOR 24020.





...CARBIN

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