Mesoscale Discussion 0036
   NWS Storm Prediction Center Norman OK
   0954 AM CST Sat Jan 11 2020

   Areas affected...Portions of eastern MS and western AL

   Concerning...Tornado Watch 13...

   Valid 111554Z - 111730Z

   The severe weather threat for Tornado Watch 13 continues.

   SUMMARY...The greatest wind and tornado threat over the next couple
   of hours should be focused across parts of eastern Mississippi and
   western Alabama.

   DISCUSSION...An extensive squall line extends from far southeastern
   LA into parts of central/eastern MS at 1550Z. Multiple inversions
   noted in the 760-580 mb layer from the 12Z BMX sounding have acted
   to limit the vertical depth of this line. But, very strong flow
   noted in the boundary layer from area VWPs owing to a 60-75+ kt
   southerly low-level jet is encouraging strong to severe wind gusts
   within the line and related damage reports across central MS.
   Special soundings from UAH in Haleyville, AL from 12Z and 13Z show
   an increase in low-level moisture coupled with a slight erosion of
   the inversion around 760 mb and gradual cooling of mid-level
   temperatures. Short-term guidance suggests these trends will
   continue across parts of eastern MS and western AL over the next
   couple of hours as the upper trough over the southern Plains ejects
   northeastward.

   Given the linear nature of the ongoing convection across eastern MS
   and the enhanced flow present at low levels, damaging winds will
   probably be the main severe threat in the short term. However, the
   airmass downstream is expected to continue destabilizing through the
   remainder of the morning and into the early afternoon, with MLCAPE
   of 1000-1500 J/kg potentially developing across parts of western AL.
   Very strong low-level shear, with effective SRH of 400-600+ m2/s2,
   suggests that low-level mesocyclones embedded within the line will
   be capable of producing tornadoes. The potential for supercells
   either within the line or just ahead of it remains unclear. But, if
   supercells do develop, then strong tornadoes will be possible,
   especially with eastward extent into AL where the most favorable
   thermodynamic and kinematic environment will likely exist this
   afternoon.

   ..Gleason.. 01/11/2020

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

   ATTN...WFO...BMX...MOB...JAN...

   LAT...LON   31178963 32168944 33398896 33608869 33658839 33678815
               33638788 33538769 33188758 32438773 31568796 31048833
               31028932 31178963