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URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 797

NWS STORM PREDICTION CENTER NORMAN OK

605 PM MDT SAT AUG 2 2008



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       CENTRAL MONTANA



EFFECTIVE THIS SATURDAY NIGHT FROM 605 PM UNTIL MIDNIGHT MDT.



HAIL TO 1 INCH 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 75

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 30 MILES SOUTH

SOUTHWEST OF HELENA MONTANA TO 95 MILES EAST OF LEWISTOWN

MONTANA.  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.



OTHER WATCH INFORMATION...CONTINUE...WW 795...WW 796...



DISCUSSION...HIGH TSTMS CLUSTERS EXPECTED TO PERSIST THROUGH MID TO

LATE EVENING IN AREA OF ASCENT DOWNSTREAM FROM ID UPR IMPULSE.

COMBINATION OF SEASONABLY STRONG...UNIDIRECTIONAL DEEP WSW

FLOW...WITH DEEPLY MIXED BOUNDARY LAYER...AND ELY NEAR-SFC FLOW

COULD YIELD BOWING SEGMENTS/ FORWARD PROPAGATING CLUSTERS WITH HIGH

WIND AND MARGINALLY SVR HAIL.



AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT

TO 1 INCH. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60 KNOTS.

A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 400. MEAN STORM MOTION

VECTOR 25040.





...CORFIDI

