Mesoscale Discussion 1892
   NWS Storm Prediction Center Norman OK
   0216 AM CST Thu Dec 31 2020

   Areas affected...Portions of southwest TX...including the Big Bend
   region

   Concerning...Heavy snow 

   Valid 310816Z - 311415Z

   SUMMARY...Heavy snow, with rates of 1 to 2 inches per hour, will
   likely continue this morning.

   DISCUSSION...An upper low evident on water vapor satellite imagery
   over northern Mexico will continue to move slowly eastward this
   morning. Low-level thermal profiles will likely remain cold enough
   behind a surface front to support mainly snow, with perhaps a little
   sleet mixed in based on some bright banding in reflectivity and
   lowered CC values in recent radar imagery from KMAF. Strong low to
   mid-level frontogenetic forcing along with saturation through the
   dendritic growth zone will likely support heavy snow in a relatively
   narrow southwest to northeast band from the Big Bend into parts of
   southwest TX through the early morning. Snowfall rates of 1-2 inches
   per hour appear likely for several hours within this slow moving
   band, particularly in the higher terrain of the Big Bend region into
   the Stockton Plateau, where orographic lift should enhance snowfall
   rates. Dry mid-level air on the back side of this band and the upper
   low should provide a fairly sharp cut off to the heavy snow across
   west TX. With time, this band should pivot slowly east-northeastward
   in tandem with the eastward progression of the upper low.

   ..Gleason.. 12/31/2020

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

   ATTN...WFO...EWX...SJT...MAF...

   LAT...LON   29570435 30040416 30870333 31400261 31980164 32030119
               31700087 31420107 31170124 30860144 30460148 30050154
               29740153 29750186 29760222 29630265 29240279 28930313
               29270405 29570435