MESOSCALE DISCUSSION 1184
   NWS STORM PREDICTION CENTER NORMAN OK
   0240 PM CDT SAT JUN 11 2011
   
   AREAS AFFECTED...PART OF ERN WYOMING AND SE MONTANA INTO WRN SOUTH
   DAKOTA AND THE NEBRASKA PANHANDLE
   
   CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 
   
   VALID 111940Z - 112145Z
   
   A WW LIKELY WILL BE NEEDED WITHIN THE NEXT 1 TO 2 HOURS.
   
   BENEATH VERY STEEP MID-LEVEL LAPSE RATES ASSOCIATED WITH WARM AND
   CAPPING ELEVATED MIXED LAYER...SIGNIFICANT BOUNDARY LAYER
   DESTABILIZATION IS ONGOING ASSOCIATED WITH CONTINUED SURFACE HEATING
   AND MOISTENING SOUTHEASTERLY UPSLOPE FLOW.  GUIDANCE IS SUGGESTIVE
   THAT MIXED LAYER CAPE ON THE ORDER OF 1000-2000 J/KG... PERHAPS
   LOCALLY HIGHER...MAY BE REACHED AS A SHORT WAVE IMPULSE LIFTS
   NORTHEAST OF THE NORTHERN ROCKIES LATE THIS AFTERNOON.  SCATTERED
   CONVECTIVE DEVELOPMENT IS ALREADY UNDERWAY OFF THE HIGHER
   TERRAIN...AND IT APPEARS THAT LOW-LEVEL WARM ADVECTION AND
   CONVERGENCE WILL BE SUFFICIENT TO SUPPORT SCATTERED NEW CONVECTIVE
   DEVELOPMENT NEAR THE BLACK HILLS AND ADJACENT HIGH PLAINS BY THE
   21-23Z TIME FRAME.  VERTICAL SHEAR NEAR A WESTERLY 40+ KT 500 MB JET
   NOSING OUT OF WYOMING WILL BE FAVORABLE FOR SUPERCELLS...WITH
   SIZABLE CLOCKWISE CURVED LOW-LEVEL HODOGRAPHS SUPPORTIVE OF THE RISK
   FOR ISOLATED TORNADOES...IN ADDITION TO LARGE HAIL.
   
   ..KERR.. 06/11/2011
   
   
   ATTN...WFO...LBF...UNR...CYS...BYZ...
   
   LAT...LON   41670423 43430464 45330538 45440385 44030171 41830172
               41190256 41670423