From the NWS for 12/16:

Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
MODERATE 18,127 1,064,056 Jackson, MS…Alexandria, LA…Vicksburg, MS…Clinton, MS…Pearl, MS…
ENHANCED 39,104 2,055,280 Baton Rouge, LA…Lake Charles, LA…Monroe, LA…Hattiesburg, MS…Meridian, MS…
SLIGHT 93,471 9,546,243 New Orleans, LA…Birmingham, AL…Montgomery, AL…Mobile, AL…Huntsville, AL…
MARGINAL 53,683 7,336,335 Columbus, GA…Chattanooga, TN…Beaumont, TX…Sandy Springs, GA…Murfreesboro, TN…
 Forecast Discussion
   SPC AC 161925

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0125 PM CST Mon Dec 16 2019

   Valid 162000Z - 171200Z

   ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS FROM PORTIONS OF
   CENTRAL LOUISIANA INTO CENTRAL MISSISSIPPI...

   ...SUMMARY...
   Numerous severe thunderstorms will continue to affect parts of the
   Lower Mississippi Valley region this afternoon and evening, and into
   portions of Alabama and the Tennessee Valley.  Several tornadoes --
   including a couple of long-track/significant ones -- along with
   damaging winds, remain the primary hazards. The peak tornado risk is
   expected through early evening, centered on northern and central
   Louisiana into central Mississippi.

   ...Discussion...
   Overall forecast reasoning and expectations as laid out in the prior
   outlook remain valid, as an area of thunderstorms -- including
   several severe/supercell storms -- continues to move eastward across
   the Sabine and lower Mississippi Valleys.  The most significant
   severe weather is ongoing across portions of central Louisiana and
   vicinity at this time -- i.e. across western portions of the ENH and
   MDT risk areas -- where a couple of long-track/damaging tornadoes
   have occurred over the past couple of hours.  Given a similarly
   favorable downstream environment, expect this risk to continue over
   the next several hours, before diminishing later tonight as storms
   -- and the parent cold front -- shift eastward into a less unstable
   environment.