MESOSCALE DISCUSSION 0512
   NWS STORM PREDICTION CENTER NORMAN OK
   1127 PM CDT THU APR 21 2011
   
   AREAS AFFECTED...NRN OK INTO SRN AND ERN KS
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 220427Z - 220700Z
   
   STORMS ARE EXPECTED TO FORM ACROSS FAR NRN OK INTO SRN AND ERN KS
   OVER THE NEXT SEVERAL HOURS...CONTINUING INTO FRIDAY MORNING. VERY
   LARGE HAIL WILL BE POSSIBLE AND A WW MAY BE REQUIRED BY 07-08Z.
   
   00Z SOUNDINGS FROM AROUND THE REGION INDICATE VERY STEEP MID TO
   UPPER LEVEL LAPSE RATES AND STRONG INSTABILITY IN PLACE WITH AMPLE
   DEEP LAYER SHEAR FOR STORM ORGANIZATION AHEAD OF AN UPPER TROUGH NOW
   BEGINNING TO AFFECT THE CNTRL/SRN HIGH PLAINS. WITH A PERSISTENT
   SWLY LOW LEVEL LET...MOISTURE AS SEEN ON 00Z OUN AND LMN SOUNDINGS
   WILL CONTINUE TO STREAM NWD ACROSS OK AND INTO KS...AND EVENTUALLY
   WRN MO.
   
   AS THE MOIST AND UNSTABLE AIR MASS CONTINUES NWD...FORCING
   ASSOCIATED WITH WARM ADVECTION AND THE LOW LEVEL JET SHOULD BREACH
   THE CAPPING INVERSION JUST BELOW 700 MB...WITH AN ERUPTION OF STRONG
   TO SEVERE CONVECTION POSSIBLE FROM FAR N CNTRL OK INTO MUCH OF ERN
   KS AND MOVING INTO WRN MO BY MORNING.  VERY LARGE HAIL WILL BE THE
   PRIMARY THREAT WITH THESE STORMS.
   
   ..JEWELL.. 04/22/2011
   
   
   ATTN...WFO...SGF...EAX...TSA...TOP...ICT...OUN...GID...DDC...
   
   LAT...LON   36449532 36589702 36769820 37319875 38119889 38919839
               39719730 39899579 39779464 39309426 38289416 37009432
               36839440 36449532