Mesoscale Discussion 0030
   NWS Storm Prediction Center Norman OK
   0612 AM CST Sat Jan 11 2020

   Areas affected...Western KY...Middle TN...Northern AL

   Concerning...Severe potential...Watch possible 

   Valid 111212Z - 111345Z

   Probability of Watch Issuance...60 percent

   SUMMARY...A downstream watch will likely be needed across middle TN
   and northern AL, and perhaps as far north as western KY, as the
   convective line continues eastward. Primary threats are strong wind
   gusts and QLCS tornadoes.

   DISCUSSION...Northern portion of the extensive convective line
   stretching from southern IN southwestward into southern LA has
   recently shown better overall organization, evidenced by a sharper
   reflectivity gradient along the leading edge as well as increased
   forward speed. This has occurred as the line continues eastward into
   a very impressive kinematic environment. Recent mesoanalysis
   estimates over 80 kt at 850 mb across far southwest KY and adjacent
   northwest TN. Outside of this maximum, mesoanalysis shows a very
   large area of 70+ kt at 850 mb. These very strong low-level winds
   are supporting 0-1 km storm-relative helicity values from 600 to 800
   m2/s2. Additionally, this portion of the line has become more
   favorably aligned with the deep layer shear.

   The downstream thermodynamic environment is not overly favorable but
   dewpoints in the low 60s are now into middle TN with enough
   instability anticipated for storm maintenance, particularly given
   the very strong vertical shear.  All of these factors suggest the
   potential for strong wind gusts and embedded QLCS tornadoes will
   persist eastward into northern AL and middle TN. Instability will
   lessen with northern extent, but some severe weather threat may
   still exist into western KY.

   ..Mosier/Grams.. 01/11/2020

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

   ATTN...WFO...LMK...OHX...HUN...PAH...MEG...

   LAT...LON   37048808 37908755 38088688 37538643 34458650 34758808
               37048808