Mesoscale Discussion 0213
   NWS Storm Prediction Center Norman OK
   0723 PM CDT Thu Mar 19 2020

   Areas affected...Portions of southern Texas

   Concerning...Severe potential...Watch unlikely 

   Valid 200023Z - 200300Z

   Probability of Watch Issuance...20 percent

   SUMMARY...Isolated storm development is currently underway, with
   additional development possible over the next several hours. The
   sparse nature of the potential severe threat precludes a WW issuance
   at this time.

   DISCUSSION...A supercell has recently developed approximately 30
   miles west of Maverick County TX, and is expected to continue
   eastward over the next few hours. Despite widespread clouds, surface
   temperatures have been able to warm into the 80s to lower 90s, with
   dewpoints reaching into the upper 60s in spots. 7.5+ C/km mid-level
   lapse rates overspreading this heated, modestly moist airmass have
   contributed to moderate instability (2000 J/kg MLCAPE). Bulk
   effective shear values of 60+ knots also suggest that any additional
   storms that develop may also become organized and obtain at least
   transient supercell characteristics (given an elongated, mainly
   straight hodograph, observed via both RAP forecast soundings and
   KDFX VAD profiler data). 

   Low-level shear profiles are somewhat meager. In addition, RAP
   forecast soundings suggest that a deeply mixed boundary layer with
   steep (7.5+ C/km) low-level lapse rates extending up to 700 mb is in
   place. Ample evaporative cooling will be likely with the most
   intense cells, that in tandem with relatively weak low-level shear,
   may promote strong cold pool development and subsequent outflow
   dominance, as also suggested by multiple members of the 12Z HREF and
   last few HRRR runs. As such, storm longevity is in question,
   precluding the issuance for a WW at this time. Nonetheless, a
   well-mixed boundary layer may promote isolated damaging gusts, with
   steep mid-level lapse rates promoting some severe hail threat with
   the strongest storms.

   ..Squitieri/Hart.. 03/20/2020

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

   ATTN...WFO...HGX...CRP...EWX...

   LAT...LON   27629956 28630058 29180040 29669984 29889881 29939761
               29809693 28909677 28069705 27429855 27629956