MESOSCALE DISCUSSION 0765
   NWS STORM PREDICTION CENTER NORMAN OK
   0342 PM CDT FRI MAY 08 2009
   
   AREAS AFFECTED...SRN/ERN OK...N-CNTRL TX
   
   CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 
   
   VALID 082042Z - 082215Z
   
   STRONG CAPPING INVERSION SHOULD WEAKEN SUFFICIENTLY FOR TSTM
   DEVELOPMENT BY EARLY EVENING ALONG AND N OF COLD FRONT/RESIDUAL
   OUTFLOW BOUNDARY IN SRN/ERN OK INTO N-CNTRL TX. MAIN UNCERTAINTY
   REMAINS IN TIMING OF INITIATION...WITH CONSENSUS OF GUIDANCE
   SUGGESTING AROUND 22Z. GIVEN EXTREME INSTABILITY...ONCE INITIATION
   APPEARS TO BE COMMENCING A WW WILL LIKELY BE ISSUED.
   
   20Z SUBJECTIVE SURFACE ANALYSIS PLACED A LOW CENTERED 20 E
   SPS...WITH A COMPOSITE COLD FRONT/OUTFLOW BOUNDARY ARCING NEWD INTO
   CNTRL/ERN OK TO FSM AND AN ATTENDANT DRY LINE S/SWD TO THE EDWARDS
   PLATEAU. VISIBLE SATELLITE IMAGERY DEPICTS CU GRADUALLY BUILDING
   BETWEEN ABI AND MWL...WITH MORE VIGOROUS CU DEVELOPMENT BETWEEN OKC
   AND MKO. STRONG CAPPING INVERSION REMAINS NOTED ON RECENT ACARS DATA
   INVOF OKC/DAL. HOWEVER...MODIFIED FORECAST SOUNDINGS/RAOBS SUGGEST
   MLCIN SHOULD BE MINIMAL ACROSS N-CNTRL TX WHERE SURFACE TEMPERATURES
   HAVE REACHED 95 TO 100 DEG F WITH DEW POINTS FROM 65 TO 70 DEG F.
   CONTINUED HEATING AND CONVERGENCE ASSOCIATED WITH THE SWD-SAGGING
   BOUNDARY SHOULD BE SUFFICIENT FOR TSTM INITIATION AROUND 22Z. AN
   EXTREMELY UNSTABLE AIRMASS AMIDST MODERATE DEEP-LAYER SHEAR WOULD
   SUPPORT RAPID DEVELOPMENT OF SUPERCELLS WITH VERY LARGE HAIL.
   UPSCALE GROWTH SHOULD LEAD TO CLUSTERS/QUASI-LINEAR SEGMENTS WITH
   EMBEDDED SUPERCELL STRUCTURES PRODUCING LARGE HAIL/DAMAGING WINDS
   AND ISOLATED TORNADOES.
   
   ..GRAMS.. 05/08/2009
   
   
   ATTN...WFO...TSA...FWD...OUN...SJT...
   
   LAT...LON   32799770 32409842 32359896 32439918 32609924 33249843
               33609813 34219802 35039741 35729626 35949538 35809451
               35179448 34789488 34399591 33759657 32799770