

951 

WWUS20 KWNS 301504

SEL6

SPC WW 301504

COZ000-UTZ000-010000-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 576

NWS STORM PREDICTION CENTER NORMAN OK

905 AM MDT THU JUN 30 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       WESTERN COLORADO

       EASTERN UTAH



EFFECTIVE THIS THURSDAY MORNING AND EVENING FROM 905 AM UNTIL 600

PM MDT.



HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 75

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



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 95

STATUTE MILES EAST AND WEST OF A LINE FROM 40 MILES SOUTH OF

BLANDING UTAH TO 45 MILES NORTH NORTHEAST OF VERNAL UTAH.  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...STRONG-SEVERE STORMS HAVE ALREADY DEVELOPED ACROSS THE

REGION THIS MORNING IN RESPONSE TO STRONG DYNAMIC FORCING ASSOCIATED

WITH WRN UT VORTICITY MAXIMUM ACTING ON A STEEP LAPSE RATE

ENVIRONMENT.  DAYTIME HEATING COUPLED WITH PW VALUES OF .70-.90 INCH

WILL SUPPORT FURTHER AIR MASS DESTABILIZATION TODAY WITH MLCAPE

APPROACHING 1000-1500 J/KG.  AS SUCH...EXPECT STORMS TO GRADUALLY

EVOLVE INTO MULTIPLE BANDS ALONG AND AHEAD OF THE PACIFIC FRONT WITH

ATTENDANT RISKS FOR DAMAGING WINDS AND SOME HAIL.



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

TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 65

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM

MOTION VECTOR 20035.





...MEAD

