Storm Prediction Center Mesoscale Discussion 2301

   Mesoscale Discussion 2301
   NWS Storm Prediction Center Norman OK
   1147 AM CST Sat Dec 28 2024

   Areas affected...portions of eastern Texas into far western
   Louisiana

   Concerning...Tornado Watch 718...719...

   Valid 281747Z - 281915Z

   The severe weather threat for Tornado Watch 718, 719 continues.

   SUMMARY...The severe threat continues across Tornado Watches
   718-719. All severe hazards remain possible. The best chance for
   tornadoes will exist with supercells embedded in confluence bands.

   DISCUSSION...Multiple storms along a confluence band, including a
   supercell with a history of producing at least one tornado, persist
   along a Walker to Matagorda County, TX line while a QLCS is
   developing farther to the west amid an increase in synoptic forcing.
   Storms in both regimes are overspreading a destabilized boundary
   layer, characterized by 70s F surface temperatures and dewpoints,
   yielding over 2000 J/kg MLCAPE with minimal MLCINH per 17Z
   mesoanalysis. Latest regional VADs show hodographs with elongation,
   but modest low-level curvature, indicating an environment favorable
   for damaging gusts, large hail, and perhaps a few tornadoes. 

   Latest mesoanalysis shows an 80+ kt 500 mb speed max pivoting the
   base of the mid-level trough, and is poised to overspread the TX/LA
   border over the next few hours. A low-level mass response is
   expected, with intensification of the low-level jet to well over 40
   kts likely. As this occurs, enlargement of the hodographs should
   occur, especially closer to LA. Subsequently, the potential for
   damaging gusts and tornadoes (including the risk of a strong
   tornado) should increase later this afternoon. The best chance for
   any strong tornadoes will likely be with any sustained supercell
   structures associated with the confluence band, especially if a
   supercell can avoid detrimental interference from nearby storms.
   Otherwise, the damaging gust/tornado threat will also increase with
   an approaching/intensifying QLCS, which will eventually overtake
   preceding warm-sector confluence bands/storms.

   Convection continues to oscillate in intensity farther east in the
   free warm sector. Confidence is not overly high in robust severe
   thunderstorms developing in this corridor. However, any storm that
   manages to develop could become supercellular, posing a threat for
   all severe hazards.

   ..Squitieri.. 12/28/2024

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

   ATTN...WFO...LCH...SHV...HGX...FWD...EWX...

   LAT...LON   30059718 31629636 32019506 31999418 31679325 31109274
               30649256 30099298 29789413 29749556 30059718