Mesoscale Discussion 0938
   NWS Storm Prediction Center Norman OK
   0318 PM CDT Fri Jun 19 2020

   Areas affected...TX South Plains...TX Caprock...TX Low Rolling
   Plains

   Concerning...Severe potential...Severe Thunderstorm Watch likely 

   Valid 192018Z - 192215Z

   Probability of Watch Issuance...80 percent

   SUMMARY...Convective initiation is forecast to begin with
   isolated-scattered storms developing thru 5pm CDT.  Additional storm
   coverage is expected during the evening as a cluster/band grows
   upscale and moves east of the Caprock and into the Low Rolling
   Plains.

   DISCUSSION...Visible-satellite imagery shows a high-based cumulus
   field swelling near a dryline bulge equidistant from
   Clovis-Hobbs-Lubbock.  Lightning was recently detected along the
   NM/TX border as of 2010z.  A separate swelling cumulus field is
   located near the Caprock 15 mi east of Plainview.  Water-vapor
   imagery loop this morning into the afternoon shows a mid-level
   shortwave trough moving east-northeast from the Permian Basin into
   the Low Rolling Plains.  Large-scale subsidence in wake of this
   feature has probably contributed to a delay in vertical cumulus
   development up until now (mid afternoon).  As the disturbance
   gradually becomes more displaced from the dryline, expecting a few
   thunderstorms to develop from the cumulus field west-southwest of
   Lubbock during the late afternoon.

   The 18z observed Amarillo sounding showed steep mid-level lapse
   rates with a capping inversion.  The additional heating this
   afternoon has likely weakened the remaining cap.  Although
   deep-layer flow will remain modest (at or below 25 kt effective
   shear), a strengthening LLJ this evening from the TX Big Country
   into the Low Rolling Plains will promote additional storm
   development/upscale growth this evening.  Recent HRRR and CAM
   guidance has been converging towards a scenario of a band of
   north-south storms moving east across the Caprock into the Low
   Rolling Plains during the 00-03z period.  An initial large hail risk
   coupled with isolated severe gusts (60-70 mph) will probably
   transition to primarily a wind risk (60-75 mph), with peak downdraft
   intensity expected during the cell-to-line transition phase during
   the early evening.

   ..Smith/Guyer.. 06/19/2020

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

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

   LAT...LON   32510250 32390005 33539985 34650064 35060174 33910316
               33660289 32990251 32510250