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314 

WWUS20 KWNS 102148

SEL8

SPC WW 102148

MNZ000-110400-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 448

NWS STORM PREDICTION CENTER NORMAN OK

450 PM CDT SAT JUL 10 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       WEST CENTRAL MINNESOTA



EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 450 PM UNTIL

1100 PM CDT.



TORNADOES...HAIL TO 2 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 60 STATUTE

MILES EAST AND WEST OF A LINE FROM 35 MILES NORTH NORTHEAST OF

ALEXANDRIA MINNESOTA TO 55 MILES SOUTH SOUTHEAST OF ORTONVILLE

MINNESOTA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU8).



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 446...WW 447...



DISCUSSION...THUNDERSTORM DEVELOPMENT IS JUST UNDERWAY NEAR THE

MN/SD/ND BORDER REGION ALONG A NE-SW SURFACE TROUGH.  DESPITE

LARGELY NEUTRAL LARGE SCALE FORCING FOR ASCENT...STRONG SURFACE

HEATING AND CONTINUED BOUNDARY LAYER MOISTENING HAVE WEAKENED

CONVECTIVE INHIBITION IN THE ZONE OF LOW-LEVEL ASCENT ALONG THE

BOUNDARY.  MLCAPE OF 3000-3500 J/KG AND EFFECTIVE BULK SHEAR NEAR 35

KT WILL SUPPORT A FEW SUPERCELLS EARLY IN THE STORM EVOLUTION...WHEN

LOW-LEVEL HODOGRAPH CURVATURE AND MOISTURE WILL REMAIN SUFFICIENT

FOR A TORNADO OR TWO.  CONVECTIVE MODE IS EXPECTED TO TREND MORE TO

CLUSTERS LATER THIS EVENING AS A RESULT OF STORM MERGERS AND

RELATIVELY WEAK FLOW ALOFT...THOUGH THE THREAT FOR HAIL/DAMAGING

WINDS WILL PERSIST.



AVIATION...TORNADOES AND 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

550. MEAN STORM MOTION VECTOR 31015.





...THOMPSON

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