MESOSCALE DISCUSSION 0962
   NWS STORM PREDICTION CENTER NORMAN OK
   0321 PM CDT WED MAY 21 2008
   
   AREAS AFFECTED...ERN WY...SWRN SD...NEB PANHANDLE...NERN CO
   
   CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 
   
   VALID 212021Z - 212115Z
   
   LARGE SCALE FORCING APPEARS TO BE INCREASING ACROSS MUCH OF THE
   CNTRL ROCKIES AS HEIGHTS FALL AHEAD OF DIGGING UPPER LOW.  A
   SUBSTANTIAL INCREASE IN CONVECTION HAS BEEN NOTED OVER WY INTO WRN
   CO/ERN UT BENEATH THIS INCREASING ASCENT.  OF INCREASING CONCERN IS
   THAT REGION OF ERN WY WHERE SELY BOUNDARY LAYER WINDS HAVE FORCED
   MID 40S SFC DEW POINTS INTO THE HIGHER TERRAIN.  THUNDERSTORMS
   SHOULD CONTINUE TO INCREASE OVER THE MOUNTAINS OF SCNTRL/CNTRL
   WY...THEN DRIFT NWD.  WITH TIME UPDRAFTS SHOULD STRENGTHEN ALONG THE
   ERN SLOPES AND THESE SHOULD INTERACT WITH HIGHER BUOYANCY OVER ERN
   WY.  SHEAR PROFILES STRONGLY SUPPORT SUPERCELLS...BUT SUB-CLOUD RH
   MAY BE A BIT LOW FOR MORE THAN BRIEF OR WEAK TORNADOES.  LARGE HAIL
   IS THE GREATEST RISK WITH THIS ACTIVITY.
   
   FARTHER SOUTH INTO NERN CO...STRONG DRY SURGE IS LIFTING NEWD ACROSS
   CO AND CU FIELD IS EXPANDING WITHIN THIS DEEP WARM BOUNDARY LAYER. 
   THUNDERSTORMS MAY VERY WELL DEVELOP ALONG LEADING EDGE OF THIS
   SURGE...BUT MAY NOT DO SO UNTIL NEAR THE WY/NEB BORDER.  ONCE
   INITIATION OCCURS...NWD MOVEMENT WOULD ALLOW THESE STORMS TO MOVE
   INTO SERN WY/NEB PANHANDLE.
   
   ..DARROW.. 05/21/2008
   
   
   ATTN...WFO...LBF...UNR...BOU...CYS...RIW...
   
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