MESOSCALE DISCUSSION 1154
   NWS STORM PREDICTION CENTER NORMAN OK
   0212 PM CDT FRI JUN 21 2013

   AREAS AFFECTED...SERN WY THROUGH WRN NEB

   CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 

   VALID 211912Z - 212045Z

   PROBABILITY OF WATCH ISSUANCE...80 PERCENT

   SUMMARY...STORMS ARE EXPECTED TO DEVELOP AND INTENSIFY FROM SERN WY
   INTO WRN NEB THIS AFTERNOON INTO THE EVENING. TRENDS ARE BEING
   MONITORED FOR A WW WHICH WILL LIKELY BE NEEDED BY 20-21Z. LARGE HAIL
   AND DAMAGING WIND APPEAR LIKELY...BUT A COUPLE TORNADOES CANNOT BE
   RULED OUT.

   DISCUSSION...HIGH BASED CONVECTION HAS DEVELOPED WITHIN THE DRY AND
   DEEPLY MIXED REGIME OVER SERN WY. CONVECTIVELY REINFORCED BOUNDARY
   EXTENDS FROM A SFC LOW IN NCNTRL NEB SWWD INTO SERN WY THEN NWWD
   THROUGH ERN WY. THE SFC LAYER HAS BEEN CLOUDY AND RELATIVELY STABLE
   ON COOL SIDE OF THIS BOUNDARY. HOWEVER...LOW CLOUDS ARE FINALLY
   MIXING OUT WITH TEMPERATURES WARMING TO THE LOW 80S WITHIN MOIST SFC
   LAYER NORTH OF THE BOUNDARY SUPPORTING 2000-2500 J/KG MLCAPE. HIGH
   BASED STORMS MAY INTENSIFY AS THEY MOVE EWD INTO THE MOIST AND
   UNSTABLE REGIME. OTHER STORMS MAY INITIATE ALONG THE BOUNDARY OVER
   WRN NEB. THIS REGION RESIDES ALONG THE SRN PERIPHERY OF STRONGER
   SWLY WINDS ALOFT WITH 40+ KT EFFECTIVE SHEAR SUPPORTIVE OF
   SUPERCELLS. THE MAIN THREATS WILL BE LARGE HAIL AND DAMAGING WIND
   GUSTS...BUT A COUPLE TORNADOES CANNOT BE RULED OUT WHERE STORMS
   INTERACT WITH THE MODIFYING BOUNDARY.

   ..DIAL/KERR.. 06/21/2013


   ATTN...WFO...LBF...UNR...CYS...

   LAT...LON   41340413 42530498 44170497 44240426 42780374 42720183
               42140135 41440228 41340413