Mesoscale Discussion 0134
   NWS Storm Prediction Center Norman OK
   0331 PM CDT Sun Mar 18 2018

   Areas affected...parts of Texas from the Hill Country eastward

   Concerning...Severe potential...Watch possible 

   Valid 182031Z - 182230Z

   Probability of Watch Issuance...40 percent

   SUMMARY...Storms may develop/increase over the next couple of hours,
   with attendant severe potential.  WW may be needed.

   DISCUSSION...Latest surface analysis shows a warm front moving
   slowly north across north-central and northeast Texas, and a dryline
   mixing east into the Hill Country.  While the warm sector airmass
   features dewpoints in the upper 60s, the boundary layer has been
   somewhat slow to heat/destabilize due to relatively
   widespread/multi-layer cloudiness.  Clouds are gradually thinning,
   however, with resulting insolation helping to push surface-based
   CAPE above 1500 J/kg across the area.  

   While the cu field remains relatively subdued over the discussion
   area per the latest visible satellite loop, some deeper cu is noted
   just west, near the dryline.  With multiple CAM runs, and the
   operational GFS/ECMWF all showing convective development across the
   area this afternoon/early evening, is would appear possible that
   these hints of deeper dryline cumulus may gradually evolve into an
   area of thunderstorms in the next couple of hours.

   Along with ample CAPE, area VWPs confirm model forecasts of very
   strong west-southwest flow at mid levels, atop (rather weak)
   low-level southerlies.  Resulting long hodographs would support
   supercells/splitting storms -- with large hail likely the main risk
   (in addition to locally gusty/damaging winds or even a tornado).  We
   will continue to monitor cumulus evolution, as a cue for timing on
   any potential WW issuance.

   ..Goss/Guyer.. 03/18/2018

   ...Please see www.spc.noaa.gov for graphic product...

   ATTN...WFO...LCH...SHV...HGX...FWD...EWX...

   LAT...LON   29859809 30879796 31789733 32349630 32289485 31799444
               31029452 30289484 29729671 29859809