Storm Prediction Center Mesoscale Discussion 2229

   Mesoscale Discussion 2229
   NWS Storm Prediction Center Norman OK
   0125 AM CST Mon Nov 18 2024

   Areas affected...much of northwestern Texas into southwestern
   Oklahoma

   Concerning...Severe potential...Watch likely 

   Valid 180725Z - 180930Z

   Probability of Watch Issuance...80 percent

   SUMMARY...Potential for damaging wind gusts and perhaps a few
   tornadoes may begin to increase with an evolving squall line
   accelerating northeast of the Texas South Plains through much of
   northwestern Texas and southwestern Oklahoma by 3-5 AM CDT.

   DISCUSSION...Downstream of a 90+ kt 500 mb jet streak beginning to
   nose northeast of the Texas Big Bend into the Pecos Valley, strong
   forcing for ascent continues to aid the evolution of a squall line
   in advance of a deepening surface low now near/southwest of Lubbock.
   Instability is still rather weak in the presence of thermodynamic
   profiles characterized by modest mid-level lapse rates, but weak
   low-level lapse rates and modest moisture.  However, low-level and
   deep-layer shear is strong, and an ill-defined meso-beta scale
   mid-level cyclonic circulation is now progressing  northeast of
   Lubbock.  

   A number of better defined meso-gamma scale cyclonic circulations
   are evident along the line, which has been surging northeastward
   around 30 kt, to the northeast of the mid-level circulation.  This
   appears likely to propagate into the Altus OK vicinity through
   09-11Z, with the southern flank of the line progressing across the
   Abilene TX vicinity.
    
   In response to the deepening surface troughing, a gradual
   north-northwestward advection of mid 60s to near 70F surface dew
   points toward the upstream squall line will gradually contribute to
   somewhat more unstable updraft inflow.  This may also contribute to
   a boundary-layer at least marginally more supportive of downward
   momentum transfer to the surface and potential for tornadoes, as
   low-level shear intensifies beneath an 850 mb jet forecast to
   strengthen in excess of 50 kt.

   ..Kerr/Gleason.. 11/18/2024

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

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

   LAT...LON   33610035 34130064 35169968 35239810 34159800 32049873
               31479966 31470050 32160084 33610035