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000 

WWUS20 KWNS 012048

SEL8

SPC WW 012048

MTZ000-WYZ000-020400-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 648

NWS STORM PREDICTION CENTER NORMAN OK

250 PM MDT TUE JUL 1 2008



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       A LARGE PART OF CENTRAL MONTANA

       A SMALL PART OF NORTHERN WYOMING



EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 250 PM UNTIL

1000 PM MDT.



HAIL TO 2 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 100

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

NORTHWEST OF HAVRE MONTANA TO 65 MILES SOUTH OF BILLINGS MONTANA.

 FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU8).



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.



DISCUSSION...THUNDERSTORMS WILL INCREASE IN BOTH NUMBER AND

INTENSITY ACROSS THE WATCH AREA AS AIR MASS CONTINUES TO

DESTABILIZE.  WITH APPROACH OF UPPER TROUGH...SHEAR WILL BE

SUFFICIENT ALONG WITH MLCAPES TO 1500 J/KG FOR MULTICELL STORMS

INCLUDING LARGE HAIL AND LOCALLY DAMAGING WINDS.



AVIATION...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 500. MEAN STORM

MOTION VECTOR 25025.





...HALES

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