

853 

WWUS20 KWNS 271942

SEL9

SPC WW 271942

IAZ000-MNZ000-WIZ000-LMZ000-280200-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 629

NWS STORM PREDICTION CENTER NORMAN OK

245 PM CDT MON JUL 27 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHEAST IOWA

       SOUTHEAST MINNESOTA

       SOUTHERN WISCONSIN

       LAKE MICHIGAN



EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 245 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 20 MILES WEST

SOUTHWEST OF ROCHESTER MINNESOTA TO 20 MILES NORTH NORTHEAST OF

MILWAUKEE WISCONSIN.  FOR A COMPLETE DEPICTION OF THE WATCH SEE

THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU9).



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 627...WW 628...



DISCUSSION...THUNDERSTORMS ARE EXPECTED TO INCREASE IN INTENSITY AND

COVERAGE AHEAD OF SURFACE LOW TRACKING EAST FROM MN THIS AFTERNOON.

AIRMASS NEAR THE LOW AND ALONG ASSOCIATED FRONTAL ZONES HAS BECOME

STRONGLY UNSTABLE AND WEAKLY CAPPED AND THIS SHOULD FUEL ROBUST

THUNDERSTORM UPDRAFTS. MEANWHILE...DEEP-LAYER EFFECTIVE SHEAR ACROSS

THE REGION WILL LIKELY INCREASE THROUGH THE LATE AFTERNOON AND

CONTRIBUTE TO THE PERSISTENCE OF ORGANIZED STORMS/SUPERCELLS WITH

THE THREAT FOR LARGE HAIL AND DAMAGING WINDS.



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 28020.





...CARBIN

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