Storm Prediction Center Mesoscale Discussion 904

   Mesoscale Discussion 0904
   NWS Storm Prediction Center Norman OK
   0114 PM CDT Tue May 20 2025

   Areas affected...Eastern Texas into northern Louisiana

   Concerning...Severe potential...Watch possible 

   Valid 201814Z - 202015Z

   Probability of Watch Issuance...40 percent

   SUMMARY...Thunderstorms developing along a cold front across eastern
   Texas will likely pose a severe threat through late afternoon
   downstream into northern Louisiana. Watch issuance is possible as
   storm coverage becomes more clear in the next couple of hours.

   DISCUSSION...A focused band of ascent is evident in recent GOES
   imagery across east TX along an eastward moving cold front. KSHV and
   KPOE have recently sampled a couple of deeper convective towers with
   echo tops reaching up to 15-20 kft, suggesting that the probability
   for deep convective initiation is steadily increasing. Further
   heating of a very moist environment ahead of the front over the next
   couple of hours will continue to erode inhibition and promote
   thunderstorm development by around 19-21 UTC. While eastern TX/LA is
   on the southern periphery of the stronger mid-level jet core to the
   north across AR, 40-50 knot mid-level flow atop weak low-level winds
   will still support elongated, nearly-straight hodographs. This
   thermodynamic/kinematic environment will support splitting
   supercells with an attendant risk for severe gusts and large to very
   large hail (possibly as high as 1.5 to 2.5 inches). Modest warm-air
   advection across northern LA is currently supporting sufficient
   low-level veering for around 100-150 m2/s2 0-1 km SRH, which could
   support some tornado risk. However, flow within this layer is
   expected to become more uni-directional through late afternoon, so
   it is unclear if storms will intensify and migrate into the
   favorably sheared environment before low-level helicity wanes.
   Additionally, displacement from the stronger broad-scale ascent to
   the north casts some uncertainty on convective coverage through the
   afternoon. Watch issuance will likely be needed if a sufficiently
   widespread threat becomes apparent.

   ..Moore/Hart.. 05/20/2025

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

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

   LAT...LON   32179129 30899339 30619415 30579469 30759515 31119531
               31339529 31539514 32619381 32879347 33019312 33049221
               33019121 32739109 32459106 32179129 

   MOST PROBABLE PEAK TORNADO INTENSITY...100-130 MPH
   MOST PROBABLE PEAK WIND GUST...55-70 MPH
   MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN