

000 

WWUS20 KWNS 242209

SEL7

SPC WW 242209

MTZ000-WYZ000-250500-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 447

NWS STORM PREDICTION CENTER NORMAN OK

405 PM MDT SUN JUN 24 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       LARGE PART OF EASTERN MONTANA

       SMALL PART OF NORTHEAST WYOMING



EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 405 PM UNTIL

1100 PM MDT.



TORNADOES...HAIL TO 4 INCHES IN DIAMETER...THUNDERSTORM WIND

GUSTS TO 80 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE

AREAS.



THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 110 STATUTE

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

BILLINGS MONTANA TO 20 MILES SOUTH SOUTHEAST OF BAKER MONTANA.

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.



DISCUSSION...EXTREME INSTABILITY  WITH MLCAPES IN EXCESS OF 3500

J/KG COUPLED WITH STRONGLY VEERING SHEAR PROFILES  ARE IN PLACE

ACROSS MUCH OF WATCH AREA ATTM.  THE CAP IS WEAKENING OVER THE

HIGHER TERRAIN AND EXPECT RAPID DEVELOPMENT OF SEVERE THUNDERSTORMS.

 TORNADIC SUPERCELLS ARE LIKELY TO DEVELOP ACCOMPANIED BY VERY LARGE

HAIL AND DAMAGING WINDS.  ACTIVITY WILL SPREAD EWD ACROSS THE WATCH

THRU THE EVENING TOWARD THE DAKOTA BORDER WHERE SIMILAR CONDITIONS

ARE PRESENT.



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

SURFACE AND ALOFT TO 4 INCHES. EXTREME TURBULENCE AND SURFACE

WIND GUSTS TO 70 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO

600. MEAN STORM MOTION VECTOR 24035.





...HALES

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