

429 

WWUS20 KWNS 202018

SEL4

SPC WW 202018

WIZ000-LMZ000-210200-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 504

NWS STORM PREDICTION CENTER NORMAN OK

320 PM CDT TUE JUL 20 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       CENTRAL WISCONSIN

       LAKE MICHIGAN



EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 320 PM UNTIL

900 PM 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 50

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 10 MILES SOUTHWEST

OF EAU CLAIRE WISCONSIN TO 50 MILES EAST NORTHEAST OF GREEN BAY

WISCONSIN.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU4).



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 502...WW 503...



DISCUSSION...ISOLATED THUNDERSTORMS ARE INCREASING ACROSS CENTRAL WI

NEAR LEFT EXIT REGION OF MID/UPPER LEVEL JET.  COOL TEMPERATURES

ALOFT AND STEEP LAPSE RATES...COUPLED WITH FAVORABLE EFFECTIVE SHEAR

VALUES...WILL POSE A RISK OF LARGE HAIL IN STRONGER STORMS THROUGH

MID EVENING.  STORMS SHOULD DIMINISH RAPIDLY AFTER DARK.



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 450. MEAN STORM

MOTION VECTOR 30025.





...HART

