MESOSCALE DISCUSSION 1238
   NWS STORM PREDICTION CENTER NORMAN OK
   0251 PM CDT FRI JUN 19 2009
   
   AREAS AFFECTED...MUCH OF NRN NV...FAR NW UT...SWRN ID...SERN OR
   
   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 
   
   VALID 191951Z - 192115Z
   
   HIGH BASED THUNDERSTORM DEVELOPMENT IS LIKELY OVER PORTIONS OF NRN
   NV...FAR NW UT...SWRN ID AND SERN OR. SOME OF THESE STORMS MAY BE
   CAPABLE OF PRODUCING SEVERE WIND GUSTS AND HAIL...BUT THE MARGINAL
   NATURE OF THE SEVERE WEATHER THREAT SHOULD PRECLUDE A WW.
   
   A STRONG UPPER LEVEL TROUGH AND ATTENDANT SURFACE COLD FRONT ARE
   EXPECTED TO CONTINUE PROGRESSING E THROUGH THE NWRN CONUS THIS
   AFTERNOON...AND TOWARD THE GREAT BASIN/NRN ROCKIES DURING THE
   OVERNIGHT HOURS. AS COLD MID LEVEL AIR MOVES E INTO THE REGION WITH
   THE APPROACHING TROUGH...AND SURFACE TEMPERATURES WARM DURING THE
   AFTERNOON...LOW/MID LEVEL LAPSE RATES WILL STEEPEN...AIDING IN THE
   DEVELOPMENT OF MLCAPE VALUES AROUND 500 J/KG. IN ADDITION...BOUNDARY
   LAYER WILL BECOME WELL MIXED...TAKING ON AN INVERTED-V PROFILE. THIS
   THERMODYNAMIC STRUCTURE MAY FAVOR HIGH BASED THUNDERSTORMS CAPABLE
   OF PRODUCING ISOLATED DAMAGING DOWNBURST WINDS. COOLING MID LEVEL
   TEMPERATURES/STEEPENING LAPSE RATES/STRONG DEEP LAYER SHEAR MAY ALSO
   CONTRIBUTE TO HAIL PRODUCTION...THOUGH LIMITED BOUNDARY LAYER
   MOISTURE AND CAPE MAY MITIGATE LARGE HAIL THREAT SOMEWHAT.
   
   ..GARNER.. 06/19/2009
   
   
   ATTN...WFO...SLC...PIH...BOI...LKN...REV...MFR...
   
   LAT...LON   42951788 43431490 42741338 41321350 40111540 39761792
               40071963 41131997 41991975 42951788