Mesoscale Discussion 1707
   NWS Storm Prediction Center Norman OK
   0114 PM CDT Wed Sep 23 2020

   Areas affected...portions of southern LA into far southwest MS

   Concerning...Severe potential...Watch possible 

   Valid 231814Z - 232015Z

   Probability of Watch Issuance...40 percent

   SUMMARY...A few strong to severe thunderstorms capable of producing
   a couple brief tornadoes and strong gusts are possible through the
   afternoon across parts of southern Louisiana into far southwest
   Mississippi. Trends are being monitored for possible tornado watch
   issuance.

   DISCUSSION...A surface low (post-tropical cyclone Beta) resides near
   the Sabine River northeast of Beaumont TX. A warm front extends
   eastward across southern LA and pockets of stronger heating have
   allowed temperatures to warm into the upper 70s to low 80s south of
   the front. Higher dewpoints in the mid to upper 70s are also noted
   south of the front. This has allow stronger destabilization to occur
   compared to previous days with this system, with MLCAPE values
   around 500-1000 J/kg noted across southern LA. 

   Convection has increased in intensity and organization in a
   persistent band of showers and thunderstorms, sustained by low level
   convergence just ahead of the low from the south-central LA coast
   northward through Lafayette to Alexandria. Southeasterly low level
   flow south of the warm front is contributing to enhanced low level
   shear, with 0-1 km SRH around 150-250 m2/s2 noted in latest
   mesoanalysis data and regional VWP data. While deep layer shear will
   remain modest, low level shear, in conjunction with rich low level
   moisture should allow for at least transient supercell structures
   capable of locally strong gusts and perhaps a couple of brief
   tornadoes through the remainder of the afternoon.

   ..Leitman/Guyer.. 09/23/2020

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

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

   LAT...LON   31429272 31749225 31849130 31629055 31089013 30408994
               30078997 29919028 29829078 29869129 30219210 30409273
               30609292 31069290 31429272