MESOSCALE DISCUSSION 2018
   NWS STORM PREDICTION CENTER NORMAN OK
   0146 PM CDT TUE SEP 15 2009
   
   AREAS AFFECTED...ERN UT AND WRN CO
   
   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 
   
   VALID 151846Z - 152015Z
   
   MARGINALLY SEVERE HAIL AND ISOLATED DAMAGING WIND GUSTS MAY BE
   POSSIBLE WITH STORMS OCCURRING OVER ERN UT AND WRN CO. THE SEVERE
   WEATHER THREAT APPEARS TO BE TOO MARGINAL TO JUSTIFY A WW AT THIS
   TIME.
   
   A COLD CORE UPPER LEVEL LOW WAS LOCATED AT 18Z OVER CENTRAL-S
   CENTRAL UT...AND IS FORECAST TO DRIFT SLOWLY SSEWD THROUGH THE
   AFTERNOON AND INTO THE EVENING. LARGE SCALE ASCENT PRESENT ENE OF
   THE UPPER LOW COMBINED WITH STRONG DAYTIME HEATING/BOUNDARY LAYER
   DESTABILIZATION IS AIDING IN THUNDERSTORM DEVELOPMENT AND INCREASING
   COVERAGE OVER PORTIONS OF ERN UT AND WRN CO. ONE STORM MOVING NEWD
   FROM SAN MIGUEL COUNTY INTO MONTROSE COUNTY COLORADO HAS RECENTLY
   DISPLAYED DEVIANT RIGHTWARD MOTION /COMPARED TO SURROUNDING CELLS/
   ALONG WITH WEAK MID LEVEL UPDRAFT ROTATION. EFFECTIVE BULK SHEAR
   VALUES ACROSS THE REGION ARE AROUND 30-35 KT AND MID LEVEL LAPSE
   RATES RESIDE NEAR 8 C/KM...WHICH SUGGESTS THAT ADDITIONAL STORM
   ACTIVITY MAY ACQUIRE BRIEF SUPERCELLULAR ORGANIZATION...POSING A
   THREAT OF MARGINALLY SEVERE HAIL GIVEN THE COOL MID LEVEL AIRMASS.
   STEEPENING LOW LEVEL LAPSE RATES/DRY BOUNDARY LAYER MAY ALSO AID IN
   AN ISOLATED THREAT FOR DAMAGING DOWNBURST WINDS DURING THE REMAINDER
   OF THE AFTERNOON.
   
   ..GARNER.. 09/15/2009
   
   
   ATTN...WFO...GJT...SLC...
   
   LAT...LON   37601131 38601181 39771165 40621031 40700866 40040758
               38970725 37770760 37400876 37331044 37601131