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000 

WWUS20 KWNS 210459

SEL7

SPC WW 210459

MNZ000-NDZ000-SDZ000-211200-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 677

NWS STORM PREDICTION CENTER NORMAN OK

1200 AM CDT FRI SEP 21 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       WESTERN AND CENTRAL MINNESOTA

       EASTERN NORTH DAKOTA

       NORTHEAST SOUTH DAKOTA



EFFECTIVE THIS FRIDAY MORNING FROM MIDNIGHT UNTIL 700 AM CDT.



TORNADOES...HAIL TO 2.5 INCHES IN DIAMETER...THUNDERSTORM WIND

GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE

AREAS.



THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 95 STATUTE

MILES EITHER SIDE OF A LINE FROM 45 MILES WEST NORTHWEST OF

ORTONVILLE MINNESOTA TO 55 MILES EAST SOUTHEAST OF BEMIDJI

MINNESOTA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU7).



REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR

TORNADOES AND 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.



OTHER WATCH INFORMATION...CONTINUE...WW 674...WW 675...WW 676...



DISCUSSION...TSTMS/SUPERCELLS EXPECTED TO INCREASE IN STRENGTHENING

WAA ZONE ACROSS ERN ND/NE SD AND WRN/CNTRL MN OVERNIGHT AS WIND

FIELDS INTENSIFY DOWNSTREAM FROM STRONG NRN STREAM DISTURBANCE NOW

OVER MT.  QUALITY OF MOISTURE INFLOW...DEVELOPING SFC LOW AND

EXISTING WEAK WSW-ENE-ORIENTED BOUNDARY PARALLEL TO STRONG WSWLY

DEEP SHEAR SUGGEST POTENTIAL FOR A FEW SUSTAINED SUPERCELLS WITH

LARGE HAIL/HIGH WIND AND POSSIBLE TORNADOES BEFORE ACTIVITY MERGES

INTO A LARGE CLUSTER TOWARD DAWN.



AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL

SURFACE AND ALOFT TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE

WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO

500. MEAN STORM MOTION VECTOR 26040.





...CORFIDI

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