MESOSCALE DISCUSSION 0508
   NWS STORM PREDICTION CENTER NORMAN OK
   0836 PM CDT WED APR 17 2013
   
   AREAS AFFECTED...NERN THROUGH CENTRAL AND SWRN OK...PORTIONS NWRN TX
   
   CONCERNING...TORNADO WATCH 116...
   
   VALID 180136Z - 180300Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 116 CONTINUES.
   
   SUMMARY...THE THREAT FOR SUPERCELLS WITH TORNADOES...LARGE HAIL AND
   DAMAGING WINDS CONTINUES...WITH BOWING SEGMENTS PRODUCING DAMAGING
   WINDS/MESOVORTICES INCREASINGLY LIKELY THROUGH 04Z.
   
   DISCUSSION...AT 01Z...A QUASI-STATIONARY SURFACE FRONT EXTENDED FROM
   JUST W OF BVO SWWD TO NEAR OKC...WHERE THE BOUNDARY BECOMES MASKED
   BY CONVECTIVE OUTFLOWS WHICH EXTENDS SWWD FROM OKC INTO NWRN TX
   APPROX 45 S LTS. AHEAD OF THIS FRONT/OUTFLOW BOUNDARY...A MODERATE
   TO STRONGLY UNSTABLE AIR MASS REMAINS IN PLACE WITH MLCAPES RANGING
   FROM 1000 J/KG OVER NRN PORTIONS OF WW TO NEAR 2500 J/JG OVER NWRN
   TX. DEEP-LAYER SHEAR OF 45-50 KTS WILL SUPPORT THE CONTINUATION OF
   SUPERCELL STRUCTURES OVER SRN/SWRN PORTIONS OF WW...LIKELY EVOLVING
   INTO A MORE LINEAR CONVECTIVE MODE OVER TIME AS COLD OUTFLOWS MERGE.
   EFFECTIVE SRH HAS INCREASED TO 300-350 M2/S2...RESULTING IN A
   CONTINUED THREAT FOR TORNADOES WITH MORE DISCRETE STORMS OVER SWRN
   OK/NWRN TX AND FOR EMBEDDED MESOVORTICES WITH ANY BOWING SEGMENTS.
   LARGE HAIL IS ALSO LIKELY WITH SUPERCELL TSTMS GIVEN STEEP MID-LEVEL
   LAPSE RATES OVER SWRN OK/ADJACENT PORTIONS OF NWRN TX.
   
   BEHIND THE FRONT...THE POTENTIAL REMAINS FOR STORMS TO PRODUCE
   SEVERE HAIL GIVEN AMPLE DEEP LAYER SHEAR AND ELEVATED INSTABILITY.
   
   ..BUNTING/THOMPSON.. 04/18/2013
   
   
   ATTN...WFO...SGF...TSA...ICT...FWD...OUN...SJT...
   
   LAT...LON   36979753 37009477 36109452 33979670 33489830 33379959
               33519991 36979753