MESOSCALE DISCUSSION 1453
   NWS STORM PREDICTION CENTER NORMAN OK
   0319 PM CDT THU JUN 30 2011
   
   AREAS AFFECTED...NCNTRL/WRN NEB...SWRN/SCNTRL SD AND NERN WY
   
   CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 
   
   VALID 302019Z - 302115Z
   
   SEVERE THUNDERSTORM WATCH COVERING PORTIONS OF NERN WY...SWRN/SCNTRL
   SD AND NCNTRL/WRN NEB IS LIKELY...GREATER THAN 80 PERCENT
   PROBABILITY.  PRIMARY SVR THREATS THROUGH MID-EVENING WILL BE
   SVR/DAMAGING WIND GUSTS AND LARGE HAIL.
   
   HIGH-PLAINS CONVECTION HAS BEEN INCREASING STEADILY ACROSS ERN WY
   AND WRN NEB PANHANDLE AS THE BOUNDARY LAYER STRONGLY HEATS AND
   UPSLOPE FLOW BECOMES ENHANCED BY AN APPROACHING UPPER LOW.  PRIMARY
   CONCERN IS FOR THIS ACTIVITY...AND ADDITIONAL STORMS...WILL BEGIN TO
   IMPACT AREAS ON THE LOWER PLAINS/BLACK HILLS REGION WITH TIME.
   
   LATEST MESOANALYSIS PLACES ONE SFC BOUNDARY ACROSS THE BLACK HILLS
   REGION ENE INTO NCNTRL SD AND SECOND WIND SHIFT FROM EAST OF THE
   CHAMBERLAIN SD AREA INTO THE WRN NEB PANHANDLE.  AIR MASS HAS BECOME
   UNSTABLE NEAR THESE BOUNDARIES WITH MLCAPES OF 1500-2500
   J/KG...THOUGH MODIFICATION OF THE RAPID CITY RAOB SUGGESTS A
   SUBSTANTIAL AMOUNT OF CINH STILL EXISTS ON THE LOWER PLAINS. 
   SUSPECT THAT AS ASCENT CONTINUES TO INCREASE...HIGH-BASED STORMS
   WILL GRADUALLY GROW UPSCALE INTO BOWING SEGMENTS/ISOLD SUPERCELLS
   ALONG/BETWEEN AFOREMENTIONED BOUNDARIES AND ALONG THE BLACK HILLS. 
   GIVEN INCREASING VERTICAL SHEAR/ENHANCED CHANNEL OF SWLY MID-LEVEL
   FLOW ASSOCD WITH THE LOW...SVR/DAMAGING WIND GUSTS AND HAIL WILL BE
   THE PRIMARY RISKS.
   
   ..RACY.. 06/30/2011
   
   
   ATTN...WFO...ABR...LBF...UNR...
   
   LAT...LON   44340548 44560171 43450046 42450020 41620039 41240076
               41180183 41810222 42960240 43390336 43770536 44340548