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000 

WWUS20 KWNS 061932

SEL0

SPC WW 061932

MTZ000-SDZ000-WYZ000-070300-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 660

NWS STORM PREDICTION CENTER NORMAN OK

135 PM MDT SUN JUL 6 2008



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       SOUTH CENTRAL INTO SOUTHEAST MONTANA

       WESTERN SOUTH DAKOTA

       NORTHERN AND CENTRAL WYOMING



EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 135 PM UNTIL 900

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 95

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 25 MILES SOUTH OF

CODY WYOMING TO 25 MILES SOUTH SOUTHEAST OF BUFFALO SOUTH DAKOTA.

 FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU0).



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 COVERAGE AND INTENSITY

THROUGH THE EVENING AHEAD OF SLOW MOVING SHORTWAVE TROUGH MOVING

INTO THE NRN ROCKIES.  AIR MASS WILL BE MODERATELY UNSTABLE...WITH

SHEAR STRENGTHENING AND SUPPORTING BOTH SUPERCELLS AND ORGANIZED

LINES/CLUSTERS.  LARGE HAIL AND DAMAGING WINDS WILL BE LIKELY WITH

THE MORE INTENSE STORMS.



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 26020.





...EVANS

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