MESOSCALE DISCUSSION 1728
   NWS STORM PREDICTION CENTER NORMAN OK
   0531 AM CDT FRI AUG 16 2013

   AREAS AFFECTED...TX BIG COUNTRY

   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

   VALID 161031Z - 161200Z

   PROBABILITY OF WATCH ISSUANCE...20 PERCENT

   SUMMARY...MARGINALLY SEVERE WIND/HAIL WILL REMAIN POSSIBLE NEXT
   COUPLE OF HOURS WITH SOUTHWARD SURGING LINE SEGMENT. BUT WITH WEAKER
   INSTABILITY DOWNSTREAM...THIS RISK SHOULD WANE BY ABOUT 13Z.

   DISCUSSION...MERGING OF TWO CONVECTIVE OUTFLOWS HAD ENHANCED
   INTENSIFICATION OF A LINE SEGMENT NOW ACROSS THROCKMORTON TO JACK
   COUNTIES...WITH A ROBUST REFLECTIVITY GRADIENT AND SEVERE-LEVEL
   VELOCITIES AOA 3000 FT AGL. DOWNSTREAM AIR MASS IS NOT NEARLY AS
   UNSTABLE WITH WEAKER LAPSE RATES PER 00Z DFW RAOB AND 09Z ACARS
   DATA. AS THIS LINE SEGMENT SURGES PROGRESSIVELY FARTHER AWAY FROM
   THE SOURCE REGION OF STEEPER LAPSE RATES/GREATER BUOYANCY OVER THE
   TX PANHANDLE...IT WILL LIKELY WEAKEN NEAR THE I-20 CORRIDOR. THIS
   SCENARIO APPEARS REASONABLY WELL-SIMULATED BY THE 08Z HRRR.

   ..GRAMS/GOSS.. 08/16/2013


   ATTN...WFO...FWD...OUN...SJT...LUB...MAF...

   LAT...LON   33660018 33569940 33389847 33439796 33199760 32829755
               32239757 31809775 31559825 31439871 31469959 31740019
               32070054 32520077 32850078 33200069 33660018