Mesoscale Discussion 1818
   NWS Storm Prediction Center Norman OK
   0437 PM CST Fri Nov 27 2020

   Areas affected...Southeast Louisiana...southern Mississippi...and
   southwest Alabama

   Concerning...Severe potential...Watch unlikely 

   Valid 272237Z - 280030Z

   Probability of Watch Issuance...20 percent

   SUMMARY...Strong to severe winds, and perhaps a brief tornado, will
   remain possible for portions of southeast Louisiana, southern
   Mississippi, and far southwest Alabama as a line of thunderstorms
   continues to push southeast and new convection develops along a warm
   frontal zone.

   DISCUSSION...Recent radar imagery from southeast LA, southern MS,
   and southwest AL has shown shallow discrete convection developing
   along a surface warm front that is draped from southern LA into
   southern AL. These storms should remain relatively discrete, and
   strong deep layer shear has allowed for a few storms to take on
   supercell characteristics. Additionally, transient, but weak,
   velocity couplets have been noted with this activity, and given
   around 150 m2/s2 0-3 km SRH (per the KMOB and KLIX VWPs) along with
   ambient surface vorticity along the warm front, a brief tornado
   associated with this activity appears possible over the next few
   hours. 

   To the west, a line of storms continues to push to the southeast
   into southern and southeastern LA. The environment ahead of this
   line continues to feature ample (around 50 knots) deep layer shear
   and sufficient instability (500-1000 J/kg MLCAPE), suggesting that
   storm organization and intensification remains possible - especially
   for segments of the line that can become more meridionally oriented
   and normal to the deep shear vector. However, this potential may be
   limited spatially as the storms begin to exit LA into the northern
   Gulf. Increasing inhibition with the onset of diurnal cooling within
   the next 2-3 hours may also limit the severe potential. Given these
   concerns a watch is not anticipated.

   ..Moore/Grams.. 11/27/2020

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

   ATTN...WFO...MOB...JAN...LIX...LCH...

   LAT...LON   30169246 30469181 30589100 30759011 31008965 31278877
               31338813 31168778 30788782 30428796 30308840 30188912
               29908922 29578971 29349031 29319095 29459165 29639213
               29849242 30169246