Storm Prediction Center Mesoscale Discussion 2227

   Mesoscale Discussion 2227
   NWS Storm Prediction Center Norman OK
   0853 PM CST Sun Nov 17 2024

   Areas affected...Pecos and Concho Valleys of Texas north into the
   South Plains/Big Country

   Concerning...Severe potential...Watch likely 

   Valid 180253Z - 180500Z

   Probability of Watch Issuance...95 percent

   SUMMARY...Severe-weather risk will gradually increase over the next
   several hours.  Damaging wind gusts should be the primary risk
   initially, before tornado threat ramps up later tonight.  An
   initial, Severe Thunderstorm Watch will likely be required in the
   next 1 to 2 hours.

   DISCUSSION...Latest radar loop shows thunderstorms beginning to
   strengthen across portions of western Texas across the Permian Basin
   region and vicinity.  This convective increase is occurring ahead of
   a vigorous mid- and upper-level low moving east-northeastward with
   time across northern Mexico, and approaching southwestern New Mexico
   and Far Wast Texas.  As this system advances, surface cyclogenesis
   is forecast to occur over western Texas, with the low shifting
   northward as it strengthens to a position over the South Plains
   region near daybreak.

   As the surface low develops, and southeasterlies at low-levels
   respond/strengthen, a warm front currently lying
   southwest-to-northeast across the Hill Country and into Northeast
   Texas will advance rapidly northward -- allowing an increasingly
   moist warm sector to overspread much of Texas and into southwestern
   Oklahoma overnight.

   In the meantime, modest instability is indicated across the western
   half of Texas, due to weak lapse rates aloft and dewpoints in the
   upper 50s to low 60s.  Still, increasing ascent ahead of the upper
   system is supporting the aforementioned/initial thunderstorm
   development from Far West Texas to the Permian Basin.  

   As the surface low strengthens and shifts northward, an evolving
   cold front will advance eastward across western Texas -- becoming a
   focus for increasingly organized storms.  Gradual moistening and
   some steepening of lapse rates aloft will allow modest increases in
   CAPE, further supporting convective evolution.

   The wind field preceding the advancing upper system is quite strong,
   more than sufficient for supercells.  However, storm mode will
   likely tend toward a more linear configuration, with small-scale
   bowing segments expected.  Damaging wind gusts will therefore become
   an increasing possibility with time.  Despite favorably veering
   low-level flow with height, greater tornado risk will likely be
   realized later into the overnight period in tandem with the
   increasing low-level theta-e.

   ..Goss/Hart.. 11/18/2024

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

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

   LAT...LON   30500320 32180266 34000133 33730002 33019896 31559970
               30510143 30500320