

000 

WWUS20 KWNS 210413

SEL6

SPC WW 210413

MNZ000-WIZ000-LSZ000-211100-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 676

NWS STORM PREDICTION CENTER NORMAN OK

1110 PM CDT THU SEP 20 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHERN AND EASTERN MINNESOTA

       NORTHWEST WISCONSIN

       LAKE SUPERIOR



EFFECTIVE THIS THURSDAY NIGHT AND FRIDAY MORNING FROM 1110 PM

UNTIL 600 AM 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 70

STATUTE MILES EAST AND WEST OF A LINE FROM 65 MILES SOUTH

SOUTHWEST OF KENNEDY WISCONSIN TO 30 MILES NORTH OF HIBBING

MINNESOTA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU6).



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 674...WW 675...



DISCUSSION...SCTD ELEVATED TSTMS/POSSIBLE SUPERCELLS EXPECTED OVER

NE MN/NW WI THROUGH EARLY FRIDAY AS ELEVATED THETA-E ADVECTION /1/

PERSISTS IN WAKE OF DEPARTING SHORTWAVE IMPULSE NOW IN ONTARIO AND

/2/ RE-STRENGTHENS FRIDAY MORNING WITH APPROACH OF STRONG NRN STREAM

DISTURBANCE NOW IN MT.  DEGREE OF MUCAPE /AROUND 2000 J PER KG...

DERIVED FROM QUALITY OF ELEVATED MOISTURE INFLOW AND PRESENCE OF

COOL MID LVL TEMPERATURES/...AND 50 KT WSWLY MID LVL JET SUGGEST

POTENTIAL FOR SVR HAIL/POSSIBLE DAMAGING WIND AS STORMS ORGANIZE

INTO SMALL BANDS/CLUSTERS.



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 27045.





...CORFIDI

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