MESOSCALE DISCUSSION 0867 NWS STORM PREDICTION CENTER NORMAN OK 0610 PM CDT SUN MAY 22 2011 AREAS AFFECTED...CNTRL/SWRN MO...SERN KS...NWRN AR...NERN OK CONCERNING...TORNADO WATCH 325... VALID 222310Z - 230015Z THE SEVERE WEATHER THREAT FOR TORNADO WATCH 325 CONTINUES. AT 2245-23Z...REGIONAL AND HI-RES RADAR IMAGERY SHOW A CLUSTER OF HP SUPERCELLS MOVING E-SE AT AROUND 30 KT. MOST SIGNIFICANT STORM /WITH A HISTORY OF PRODUCING A TORNADO/ IN THIS CLUSTER WAS LOCATED NEAR JOPLIN AT 2248Z. SGF VWP SHOWS ENLARGED LOW-LEVEL HODOGRAPH STRUCTURE...WITH 0-1 KM SRH NEAR 200 M2 S-2. GIVEN STRONG SHEAR PROFILES RESIDE DOWNSTREAM OVER SWRN MO...ALONG WITH AXIS OF MLCAPE VALUES FROM 2500-4000 J/KG...TORNADO THREAT /POTENTIALLY STRONG/ ALONG WITH VERY LARGE HAIL SHOULD PERSIST AS HP SUPERCELL CLUSTER MOVES ACROSS THE REMAINDER OF SWRN MO. FARTHER N OVER CNTRL MO...CLUSTER OF STORMS WAS MOVING E ACROSS AN ENVIRONMENT CHARACTERIZED BY STRONG INSTABILITY AND FAVORABLE SHEAR PROFILES FOR SUPERCELLS POSING A THREAT FOR TORNADOES...LARGE HAIL AND DAMAGING WINDS. MEANWHILE OVER NERN OK...SUSTAINED STORM DEVELOPMENT APPEARS TO BE TAKING PLACE BASED ON RECENT REGIONAL REFLECTIVITY. WITH SURFACE CONDITIONS CHARACTERIZED BY TEMPERATURES IN THE MID 80S AND DEWPOINTS IN THE LOW 70S...AND 700-500 MB LAPSE RATES AROUND 7 C/KM...EXTREME INSTABILITY RESIDES AHEAD OF THIS NEW DEVELOPMENT /MLCAPE VALUES NEAR 4000 J PER KG/. AREA VWP/S AND RUC SOUNDINGS SHOW FAVORABLE WIND PROFILES FOR SUPERCELL DEVELOPMENT AS THIS ACTIVITY MOVES DOWNSTREAM ACROSS NERN OK INTO NWRN AR...WITH THE POTENTIAL FOR VERY LARGE HAIL AND TORNADOES CONTINUING INTO THE EVENING HRS. OVER S-CNTRL OK...LEFT MOVING SUPERCELL IS RAPIDLY MOVING N TOWARD THE SWRN CORNER OF WW 325. THIS STORM WILL POSE A THREAT FOR LARGE HAIL IF IT PERSISTS INTO E-CNTRL/NERN OK. ..GARNER.. 05/22/2011