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WWUS20 KWNS 012044

SEL9

SPC WW 012044

MTZ000-WYZ000-020500-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 469

NWS STORM PREDICTION CENTER NORMAN OK

245 PM MDT SUN JUL 1 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       EASTERN AND CENTRAL MONTANA

       NORTHEAST WYOMING



EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 245 PM UNTIL

1100 PM MDT.



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 130

STATUTE MILES EAST AND WEST OF A LINE FROM 25 MILES NORTH

NORTHWEST OF GLASGOW MONTANA TO 20 MILES SOUTHEAST OF SHERIDAN

WYOMING.  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 468...



DISCUSSION...WIDELY SCTD TSTMS...INCLUDING SUPERCELLS...EXPECTED TO

FORM IN AREA OF SUSTAINED...MODERATELY MOIST UPSLOPE FLOW DURING THE

NEXT FEW HOURS.  GLANCING INFLUENCE OF UPR DISTURBANCE NOW OVER NW/N

CNTRL MT...AND STRONG SFC HEATING WILL FURTHER DESTABILIZE REGION

WITH 40-50 KT DEEP WSWLY SHEAR.  A STORM OR TWO MAY ALSO FORM INVOF

DIFFERENTIAL HEATING BOUNDARY EXTENDING ENE FROM NEAR LWT.



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 24035.





...CORFIDI

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