Storm Prediction Center Mesoscale Discussion 2287

   Mesoscale Discussion 2287
   NWS Storm Prediction Center Norman OK
   0457 PM CST Thu Dec 26 2024

   Areas affected...Louisiana

   Concerning...Tornado Watch 715...

   Valid 262257Z - 270000Z

   The severe weather threat for Tornado Watch 715 continues.

   SUMMARY...Severe threat is expected to spread into central and
   southern Louisiana this evening. New tornado watch appears
   warranted.

   DISCUSSION...Strong, negative-tilt short-wave trough is ejecting
   across east TX early this evening. 500mb speed max is forecast to
   translate across northern LA which will encourage LLJ to shift north
   across the lower MS over the next 3-6hr. As this occurs, warm sector
   will recover a bit across LA, especially southwestern LA where
   surface dew points are rising through the mid 60s. This will
   contribute to near-surface based buoyancy, that appears adequate,
   for maintaining ongoing, upstream supercell activity. Latest radar
   data depicts several longer-lived supercells over southeast TX that
   will track northeast into a strongly sheared air mass, just east of
   ww715. This evolving risk likely warrants a new tornado watch
   immediately downstream.

   ..Darrow.. 12/26/2024

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

   ATTN...WFO...JAN...LCH...SHV...

   LAT...LON   29739399 31679308 31409199 29729276 29739399