MESOSCALE DISCUSSION 1615
   NWS STORM PREDICTION CENTER NORMAN OK
   1248 PM CDT SUN JUL 11 2004
   
   AREAS AFFECTED...CENTRAL/ERN MT AND WRN ND/FAR NWRN SD
   
   CONCERNING...SEVERE THUNDERSTORM POTENTIAL 
   
   VALID 111748Z - 111945Z
   
   ELEVATED CONVECTION OVER PORTIONS OF NCENTRAL/ERN MT IS LIKELY TO
   BECOME ROOTED IN THE BOUNDARY LAYER AND BEGIN POSING A THREAT FOR
   DAMAGING WINDS/LARGE HAIL AS IT MOVES INTO FAR NWRN SD/WRN ND IN THE
   NEXT 2-3 HOURS. A WW IS ANTICIPATED TO BE NEEDED BY 19Z.
   
   LEAD SHORTWAVE TROUGH IS MOVING ACROSS CENTRAL MT EVIDENT ON WV
   IMAGERY AND RECENT PASSAGE IN THE BILLINGS VWP DATA. ELEVATED
   CONVECTION IS BEGINNING TO INTENSIFY AS LOW LEVEL DESTABILIZATION
   OCCURS BENEATH MID LEVEL CAA AS EVIDENT BY 17Z GGW SOUNDING.
   MODIFICATION OF THIS SOUNDING FOR CONDITIONS SLIGHTLY SOUTHEAST
   WHERE TEMPERATURES ARE WARMER OVER ERN MT/WRN ND AND FAR NWRN SD
   INDICATES STILL AROUND 50-100 J/KG OF MLCINH. WITH A FEW MORE HOURS
   OF HEATING...SFC TEMPERATURE IN THE UPPER 80S WITH DEWPTS IN THE
   LOWER-MID 60S...CONDITIONS SHOULD BE SUFFICIENT FOR CONVECTION TO
   BECOME ROOTED IN THE BOUNDARY LAYER AND BEGIN TO POSE A SEVERE 
   THREAT. STRENGTH OF DEEP LAYER SHEAR PROFILES SUGGEST THAT
   CONVECTION SHOULD START OUT AS SUPERCELLULAR IN NATURE.
   
   FARTHER WEST OVER SCENTRAL/SWRN MT...LARGE SCALE SUBSIDENCE BEHIND
   THE SHORTWAVE WILL AID IN MAINTAINING WLY WINDS LIMITING UPSLOPE
   FLOW AND POTENTIAL FOR ANY SEVERE THUNDERSTORMS UNTIL LATER THIS
   AFTERNOON. AS COLD FRONT MOVES SWD INTO SWRN/SCENTRAL MT AND UPSLOPE
   INCREASES IN THIS AREA CONVECTION WILL THEN BECOME LIKELY. DESPITE
   STEEP LAPSE RATES AND STRONG WIND PROFILES... INSTABILITY ON THE
   ORDER OF 500-700 J/KG WOULD LIKELY BE INSUFFICIENT FOR A WW.
   
   ..CROSBIE.. 07/11/2004
   
   
   ATTN...WFO...ABR...BIS...UNR...BYZ...GGW...TFX...
   
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