

108 

WWUS20 KWNS 190037

SEL0

SPC WW 190037

MNZ000-WIZ000-LSZ000-190700-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 470

NWS STORM PREDICTION CENTER NORMAN OK

735 PM CDT THU JUN 18 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       CENTRAL MINNESOTA

       NORTHWEST WISCONSIN

       LAKE SUPERIOR



EFFECTIVE THIS THURSDAY NIGHT AND FRIDAY MORNING FROM 735 PM

UNTIL 200 AM CDT.



HAIL TO 2 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 65

STATUTE MILES EAST AND WEST OF A LINE FROM 40 MILES WEST

NORTHWEST OF KENNEDY WISCONSIN TO 5 MILES SOUTHWEST OF EAU CLAIRE

WISCONSIN.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU0).



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 464...WW 465...WW

466...WW 467...WW 468...WW 469...



DISCUSSION...CONVECTION WILL CONTINUE TO SPREAD EWD ALONG THE

SYNOPTIC WARM FRONT FROM MN INTO NW WI THIS EVENING INTO TONIGHT.

MODERATE INSTABILITY IS PRESENT ALONG AND S OF THE BOUNDARY...WHILE

DEEP LAYER VERTICAL SHEAR IS SUFFICIENT FOR ORGANIZED CONVECTIVE

SYSTEMS...INCLUDING SUPERCELLS AND BOW ECHOES.  THE PRIMARY SEVERE

THREATS APPEAR TO BE DAMAGING WINDS AND HAIL AS CONVECTION

CONSOLIDATES ACROSS MN AND THEN MOVES EWD/ESEWD ALONG THE

INSTABILITY GRADIENT INTO WI.  A SOMEWHAT COOLER BOUNDARY LAYER

COMPARED TO AREAS FARTHER S/SW...AND ONLY MODEST LOW-LEVEL SHEAR IN

00Z OBSERVATIONS AND SHORT-TERM MODEL FORECASTS SUGGEST THAT THE

TORNADO THREAT WILL BE RATHER LIMITED INTO NW WI.



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

TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. MEAN STORM

MOTION VECTOR 28035.





...THOMPSON

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