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URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 696

NWS STORM PREDICTION CENTER NORMAN OK

155 PM MDT THU OCT 7 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       LARGE PART OF WESTERN COLORADO

       LARGE PART OF EASTERN UTAH

       SMALL PART OF SOUTHERN WYOMING



EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 155 PM UNTIL

800 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 105

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

SOUTHEAST OF BULLFROG MARINA UTAH TO 35 MILES NORTHWEST OF

RAWLINS WYOMING.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU6).



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...A VIGOROUS S/WV TROUGH AND UPPER JET STREAK MOVING NEWD

INTO UT ATTM WHERE AIR MASS IS DESTABILIZING. STEEP LAPSE RATES

COUPLED WITH 50-60KT OF DEEP LAYER SHEAR AND MLCAPES TO AOA 500 J/KG

WILL BE SUFFICIENT FOR STORMS DEVELOPING INTO LINE SEGMENTS WITH

ASSOCIATED DAMAGING WIND THREAT AT AS THEY MOVE RAPIDLY NEWD.

PARAMETERS ALSO FAVOR POTENTIAL FOR ISOLATED SUPERCELLS WHICH WOULD

ENHANCE BOTH THE HAIL AND WIND THREAT.



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 450. MEAN STORM

MOTION VECTOR 23035.





...HALES

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