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457 

WWUS20 KWNS 231519

SEL7

SPC WW 231519

IAZ000-MNZ000-WIZ000-232000-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 677

NWS STORM PREDICTION CENTER NORMAN OK

1015 AM CDT SAT JUL 23 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       EXTREME NORTHEAST IOWA

       EXTREME SOUTHEAST MINNESOTA

       SOUTHWEST WISCONSIN



EFFECTIVE THIS SATURDAY MORNING AND AFTERNOON FROM 1015 AM UNTIL

300 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 50

STATUTE MILES EITHER SIDE OF A LINE FROM 15 MILES NORTHWEST OF

ROCHESTER MINNESOTA TO 20 MILES SOUTHEAST OF CAMP DOUGLAS

WISCONSIN.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU7).



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.



DISCUSSION...STORMS HAVE INTENSIFIED ALONG THE SRN END OF A QLCS

EXTENDING FROM NWRN WI INTO SERN MN.  LATEST RADAR INDICATES SRN

STORMS HAVE DEVELOPED INTO A BOW ECHO MOVING ESEWD 35 KT.  NEW

UPDRAFTS ARE FORMING ALONG THE SRN FLANK OF THE SYSTEM AND MERGING

INTO THE BOW...SUGGESTING POSSIBLE SWD EXTENSION OF THE LINE.

SATELLITE IMAGERY SHOWS A CLOUD FREE REGION DOWNSTREAM FROM THE

STORMS EXTENDING INTO PARTS OF WEST CENTRAL/SWRN WI WHERE STRONGER

HEATING AND DESTABILIZATION WILL OCCUR...WITH INCREASING THREAT FOR

DAMAGING WINDS DURING THE LATE MORNING/EARLY 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 500. MEAN STORM

MOTION VECTOR 27030.





...WEISS

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