Mesoscale Discussion 0001
   NWS Storm Prediction Center Norman OK
   0215 PM CST Thu Jan 02 2020

   Areas affected...Portions of southern/eastern LA...southern/central
   MS...and far western AL

   Concerning...Severe potential...Watch possible 

   Valid 022015Z - 022245Z

   Probability of Watch Issuance...40 percent

   SUMMARY...Storms across Louisiana will continue moving northeastward
   this afternoon while posing an isolated damaging wind and tornado
   threat. Watch issuance is possible in the next couple of hours.

   DISCUSSION...Storms have recently developed in a
   southwest-to-northeast oriented band over parts of LA as large-scale
   ascent associated with an approaching upper trough gradually
   overspreads this area. Surface pressure falls around 2 to 3 mb in
   the past two hours have been observed from east TX across LA and
   into much of MS and western AL. Short-term guidance suggests a weak
   low will consolidate over central LA and then develop northeastward
   along a surface boundary into MS and eventually northwestern AL. A
   weakly unstable airmass characterized by mid 60s to lower 70s
   surface dewpoints will exist downstream of ongoing convection in LA.
   Still, MLCAPE is expected to reach no more than 500-750 J/kg across
   the warm sector this afternoon and early evening owing to modest
   diurnal heating and poor mid-level lapse rates.

   Recent VWP estimates from area radars show generally southwesterly
   winds rapidly strengthening with height through mid/upper levels,
   which is supporting 50-70+ kt of effective bulk shear. But, this
   enhanced flow aloft should remain largely parallel to the
   orientation of the convective band, which will probably tend to
   limit the potential for a more discrete mode. Storms may also have
   the tendency to become undercut by their own outflow, especially
   with eastward extent into MS and far western AL. Regardless,
   isolated strong to damaging winds appear to be the main threat as
   these storms move northeastward this afternoon and early evening
   given the strong flow present just off the surface. A couple
   tornadoes may also occur since strong low-level shear will be
   present ahead of the line.

   Across east-central MS and far western AL, ongoing precipitation
   associated with strong low-level warm air advection is forecast to
   shift northeastward over the next several hours. Although the
   near-term severe risk across this area is low, some threat may
   eventually exist as the low-level airmass gradually destabilizes
   from south to north later this afternoon and evening.

   Radar and observational trends will continue to be monitored for
   signs of increasing storm intensity and organization, with watch
   issuance possible over the next couple of hours.

   ..Gleason/Hart.. 01/02/2020

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

   ATTN...WFO...BMX...JAN...LIX...LCH...

   LAT...LON   30489249 31299197 32099138 33089011 33618883 33618825
               33298805 32678840 31448988 30829069 30039200 30019274
               30489249