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URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 280

NWS STORM PREDICTION CENTER NORMAN OK

220 PM MDT MON JUN 7 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHWEST COLORADO

       CENTRAL AND NORTHERN UTAH

       FAR SOUTHWESTERN WYOMING



EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 220 PM UNTIL 900

PM MDT.



HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 80

MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 120

STATUTE MILES EAST AND WEST OF A LINE FROM 45 MILES EAST OF

MILFORD UTAH TO 65 MILES NORTHEAST OF VERNAL UTAH.  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...COMBINATION OF APPROACHING UPPER TROUGH AND COLD FRONT

SHOULD AID IN THUNDERSTORMS DEVELOPING ACROSS THE REGION INTO THE

EVENING HOURS. STRONG INSTABILITY AND DEEP LAYER SHEAR FAVORS

SUPERCELLS WITH HAIL AND DAMAGING WINDS...ESPECIALLY ACROSS MUCH OF

NRN/CENTRAL UT. IN FAR NERN UT/SWRN WY AND NWRN CO...A DEEPLY MIXED

BOUNDARY LAYER TO 500 MB SUGGESTS THAT THE MAIN THREAT IN WILL BE

DAMAGING WINDS.



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

TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 70

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 450. MEAN STORM

MOTION VECTOR 27030.





...IMY

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