Mesoscale Discussion 0170
   NWS Storm Prediction Center Norman OK
   0132 PM CDT Thu Mar 12 2020

   Areas affected...Southern IL...Far Southwest IN...Western KY...Far
   Southeast MO/MO Bootheel

   Concerning...Tornado Watch 46...

   Valid 121832Z - 122030Z

   CORRECTED FOR INCORRECT GEOGRAPHIC REFERENCE

   The severe weather threat for Tornado Watch 46 continues.

   SUMMARY...The threat for damaging wind gusts and line-embedded
   tornadoes is expected to increase over the next few hours.

   DISCUSSION...Bowing segment moving across southeast MO/southern IL
   has recently shown slightly improved linear structure. Striated
   velocity signatures from KLSX suggest this more linear structure is
   currently resulting from a bore elevated atop the stable surface
   layer and not surface-based outflow. However, as the cluster
   continues to move downstream, the air mass is expected to become
   increasingly supportive of surface-based convective, particularly
   once it moves into western KY. Low/mid-level wind fields will also
   increase as the jet max currently extending from northern AR into
   southern MO spreads eastward. Expectation is for the effective SRH
   to increase to over 400 m2/s2 ahead of the line over western KY by
   20-21Z. As a result of these environmental changes, the threat for
   damaging wind gusts and/or line-embedded tornadoes is expected to
   increase.

   A more discrete storm also exists ahead of the line. More cellular
   nature of this storm and the improving downstream air mass suggests
   potential exists for this storm to develop into a mature supercell
   capable of producing damaging wind gusts and/or a tornado.

   ..Mosier.. 03/12/2020

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

   ATTN...WFO...PAH...LSX...

   LAT...LON   37118970 37519033 38159020 38588941 38298793 37628745
               36918809 37118970