Mesoscale Discussion 1819
   NWS Storm Prediction Center Norman OK
   0240 PM CST Sun Nov 29 2020

   Areas affected...Parts of southeastern Louisiana...southeastern
   Mississippi....southwestern Alabama and the western Florida
   Panhandle

   Concerning...Severe potential...Watch unlikely 

   Valid 292040Z - 292315Z

   Probability of Watch Issuance...20 percent

   SUMMARY...Some potential exists for the development of a supercell
   or two, accompanied by the risk for producing a tornado, as a
   deepening surface low continues to migrate inland of the coast
   through 4-6 PM CST.  It is not yet clear that a severe weather watch
   will be needed, but trends will continue to be monitored.

   DISCUSSION...A surface frontal low continues to develop inland of
   north central Gulf coastal areas (near New Orleans, LA as of 20Z). 
   The Rapid Refresh has been indicating further deepening is likely
   through the remainder of the afternoon, with a more rapid
   north-northeastward migration toward the Selma AL vicinity by
   30/00Z, as a vigorous upstream short wave trough begins pivoting
   northeastward through the lower Mississippi Valley.

   Strongest southerly 850 mb flow is now inland of the coast in a belt
   across southeastern Mississippi through much of southern Alabama and
   the western Florida Panhandle, where clockwise-curved low-level
   hodographs are largest and becoming most conducive to potential for
   storms capable of producing tornadoes.  Deep-layer wind fields are
   expected to become more favorable, as west-southwesterly flow in the
   700-500 mb layer strengthens across this region through early
   evening.

   More problematic to severe weather potential, seasonably moist
   boundary-layer air remains largely confined to areas offshore of the
   Gulf coast, and forecast soundings are suggestive that a residual
   near surface stable layer may persist inland of coastal areas even
   as the surface low center migrates inland.  However, trends in
   latest objective surface analysis hint that at least some
   modification may be underway.  

   Given the deepening nature of the surface low, it may not be out of
   the question that boundary-layer destabilization could become
   sufficient to support an intensifying warm sector storm or two late
   this afternoon.  If this occurs, the wind profiles will be conducive
   to the evolution of supercells, with the potential to produce a
   tornado.

   ..Kerr/Hart.. 11/29/2020

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

   ATTN...WFO...TAE...BMX...MOB...LIX...

   LAT...LON   31418873 31848836 32118767 31218670 29658512 29608753
               29578821 29448916 29608983 31418873