MESOSCALE DISCUSSION 0853 NWS STORM PREDICTION CENTER NORMAN OK 0106 PM CDT SUN MAY 22 2011 AREAS AFFECTED...ERN KS...NERN OK...MUCH OF SRN AND SWRN MO...NRN AR CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY VALID 221806Z - 222000Z A TORNADO WATCH WILL BE ISSUED SHORTLY. AN EXTREMELY UNSTABLE AIR MASS HAS DEVELOPED E OF THE DRYLINE WITH DEWPOINTS NEAR 70 F BENEATH STEEP MID LEVEL LAPSE RATES. NEARLY ALL CONVECTIVE INHIBITION HAS BEEN ERODED...THUS EXPECTED CU ALONG THE DRYLINE TO ERUPT INTO INTENSE SUPERCELLS. EXTREMELY LARGE HAIL IS LIKELY...AND ALTHOUGH LOW LEVEL SHEAR IS A BIT MARGINAL...IT WILL BE MORE THAN SUFFICIENT FOR TORNADOES GIVEN EXTREME INSTABILITY. ..JEWELL.. 05/22/2011