Mesoscale Discussion 1866
   NWS Storm Prediction Center Norman OK
   0327 PM CST Wed Dec 23 2020

   Areas affected...east texas and western Louisiana

   Concerning...Severe potential...Watch unlikely 

   Valid 232127Z - 232330Z

   Probability of Watch Issuance...20 percent

   SUMMARY...Additional storm development and intensification will be
   possible over the next several hours ahead of a strong cold front.
   Storms with a conditional risk for damaging wind gusts and perhaps a
   tornado will be possible though considerable uncertainty remains.

   DISCUSSION...Afternoon satellite imagery showed towering cumulus and
   weak thunderstorms developing along and ahead of a strong cold front
   from eastern Texas to western Louisiana. This cold front is
   associated with a central US trough over the Great Plains and upper
   Midwest.

   SPC mesoanalysis shows remaining CIN has gradually eroded across
   portions of eastern Texas and western Louisiana where diurnal
   heating has taken place ahead of the cold front. With boundary-layer
   dewpoints in the mid 60s F, and 500 mb temperatures near -20 C ahead
   of the upper trough, sufficient MLCAPE (500-1000 J/Kg) for deep
   convection has developed. Regional VAD/VWPs show bulk shear near
   60-70 kts across much of the area. The favorable cape/shear combo
   may support severe thunderstorm development/intensification along
   the cold front and in the free warm sector over the next couple of
   hours. A mixed storm mode with a transition to predominately linear
   is expected as the cold front begins to surge eastward. Strong
   low-level wind fields will support enlarged hodographs with a highly
   conditional threat of damaging wind gusts and perhaps a couple of
   tornadoes.

   The considerable uncertainty on the need for a watch revolves around
   the presence of weak destabilization ahead of the ongoing
   convection. Most hi-res guidance points toward storms remaining
   relatively weak and disorganized until after nightfall when
   increasing lift from the low-level jet and surging cold front
   develop. With uncertainty on storm intensity/coverage through the
   next few hours, a watch is unlikely, but a conditional threat for
   severe weather with any developing storms remains.

   ..Lyons/Guyer.. 12/23/2020

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

   ATTN...WFO...LCH...SHV...HGX...

   LAT...LON   30179490 31339490 32919393 33009278 32879233 32239208
               31189221 30279277 29799312 29749377 29629438 30179490