Mesoscale Discussion 1828
   NWS Storm Prediction Center Norman OK
   0315 PM CST Wed Dec 02 2020

   Areas affected...Portions of the Middle/Upper TX Coast

   Concerning...Severe potential...Watch unlikely 

   Valid 022115Z - 022245Z

   Probability of Watch Issuance...20 percent

   SUMMARY...Any isolated hail, strong/gusty wind, or brief tornado
   threat should focus along and near a small part of the Middle/Upper
   Texas Coast this afternoon.

   DISCUSSION...Multiple supercells have been observed by radar off the
   Middle/Upper TX Coast this afternoon. This convection is largely
   being aided by modest low-level warm advection, as stronger
   large-scale forcing for ascent associated with a mid/upper-level low
   over the southern High Plains remains displaced to the north of this
   region. This activity has also slowed destabilization across the
   middle/upper TX Coast, even as surface dewpoints have gradually
   increased into the mid 60s along the immediate coast. Even so,
   modest heating has recently allowed surface temperatures to warm
   into the low 70s along a small part of the middle TX Coast ahead of
   weak front. There is a narrow (about 1-2 counties wide) corridor
   along the coast where some surface-based instability resides, with
   MLCAPE generally ranging from 500-1250 J/kg. Around 35-45 kt of
   mid-level flow evidenced on recent VWPs from the KHGX radar is
   supporting similar values of effective bulk shear across this
   region.

   A small storm has recently strengthened in Matagorda County TX along
   the coast, moving slowly east-northeastward. This storm, and any
   others that can develop over land in the small but favorable
   parameter space along/near the coast, may pose an isolated severe
   threat, with hail and strong/gusty downdraft winds possible in the
   strongest cores. A brief tornado also cannot be ruled out, although
   low-level flow is not overly strong across the narrow warm sector.
   The northern extent of this marginal severe threat (into the Houston
   metro area) will likely be limited by widespread cloud cover, lower
   surface dewpoints, and decreasing surface-based instability. Given
   the expected limited spatial and temporal extent of the severe risk,
   watch issuance will probably not be needed.

   ..Gleason/Bunting.. 12/02/2020

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

   ATTN...WFO...HGX...

   LAT...LON   28879534 28599586 28529614 28829632 29159617 29519616
               29689573 29739509 29639480 29529466 29329470 28879534