ZCZC SPCSWOMCD ALL ACUS11 KWNS 232337 SPC MCD 232337 OKZ000-TXZ000-240100- MESOSCALE DISCUSSION 0729 NWS STORM PREDICTION CENTER NORMAN OK 0637 PM CDT SAT MAY 23 2015 AREAS AFFECTED...SOUTHERN/CENTRAL OK AND NORTH TX CONCERNING...TORNADO WATCH 197... VALID 232337Z - 240100Z THE SEVERE WEATHER THREAT FOR TORNADO WATCH 197 CONTINUES. SUMMARY...HEAVY RAINFALL ASIDE...SHORT-TERM TORNADO THREAT WILL LIKELY REMAIN MAXIMIZED ACROSS SOUTH-CENTRAL/EAST-CENTRAL OK THROUGH EARLY/MID-EVENING. TORNADO WATCH 197 CONTINUES UNTIL 07Z...WHILE ADDITIONAL PORTIONS OF EAST-CENTRAL OK MAY REQUIRE AN ADDITIONAL TORNADO WATCH. DISCUSSION...A COMPOSITE NORTHEAST-SOUTHWEST ORIENTED SQUALL LINE CONTINUES TO SLOWLY SPREAD EAST-SOUTHEASTWARD ACROSS NORTH-CENTRAL/SOUTHWEST OK AS OF 2330Z/630 PM CDT...WHILE OTHER SEMI-DISCRETE STORMS CONTINUE TO QUICKLY DEVELOP/INTENSIFY TO THE EAST-SOUTHEAST OF THE SQUALL LINE ACROSS SOUTH-CENTRAL/CENTRAL OK. THESE SEMI-DISCRETE STORMS HAVE BEEN VERY QUICK TO ACQUIRE LOW-LEVEL ROTATION INCLUDING A HISTORY OF SEVERAL TORNADOES IN AREAS TO THE IMMEDIATE WEST/SOUTH OF THE OKC METRO AS OF 630 PM CDT. SCENARIO WILL LIKELY REMAIN VERY FAVORABLE FOR AT LEAST TRANSIENT SUPERCELLS WITH A TORNADO WITHIN A TROPICAL-LIKE AIR MASS CHARACTERIZED BY LOWER 70S F SURFACE DEWPOINTS. LOW-LEVEL WINDS REMAIN BACKED TO SOUTHEASTERLY EAST/SOUTHEAST OF THE SQUALL LINE...WHICH IS CONTRIBUTING TO STRONG LOW-LEVEL SRH WITH LATEST WSR-88D VWP DATA FROM KTLX INDICATING AROUND 350 M2/S2 OF 0-1 KM SRH. ..GUYER.. 05/23/2015 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...TSA...FWD...OUN... LAT...LON 34179951 35129831 35819736 36459609 36489521 34649489 33169678 33379891 34179951 NNNN