Mesoscale Discussion 0518
   NWS Storm Prediction Center Norman OK
   1250 PM CDT Sun May 03 2020

   Areas affected...Southeastern Missouri...northeastern
   Arkansas...southern Illinois...western Kentucky and Tennessee

   Concerning...Severe Thunderstorm Watch 157...158...

   Valid 031750Z - 031915Z

   The severe weather threat for Severe Thunderstorm Watch 157, 158
   continues.

   SUMMARY...Potential for strong wind gusts and perhaps a short-lived
   tornado or two probably will increase through 3-5 PM CDT with an
   organized cluster of thunderstorms spreading into and across the
   region.

   DISCUSSION...The organized convective system is maintaining strength
   and speed of forward (east-southeastward) progagation around 50 kt,
   toward areas of the Mississippi Valley near and just south of the
   Ohio River.  Its associated surface cold pool appears to be
   strengthening, with 2-3 mb 2 hourly surface pressure rises evident
   in 17Z surface observations at Vichy and West Plains, Missouri.

   Strongest updrafts are now focused on the southern flank of the
   system which has shifted south of the state border into northern
   Arkansas, near/east-southeast of Flippin.  This is near the northern
   periphery of very steep mid-level lapse rates associated with warm
   elevated mixed-layer air, which may be contributing to the
   occasional production of very large hail in excess of 2 inches based
   on MRMS data.

   Otherwise, farther north and northeast, the primary severe threat
   probably has transitioned to potentially damaging winds along the
   strengthening gust front.  The warming and moistening boundary layer
   ahead of the gust front continues to destabilize, and convection
   still seems likely to become rooted increasingly closer to the
   surface through 20-21Z.  Due to weaker flow near the surface, weaker
   mean flow in the convective layer may result in some slowing of
   forward propagation.  However, further strengthening of the cold
   pool and rear inflow seems probable, which may be accompanied by
   increasing potential for intensifying mesovortices near the gust
   front, along with locally enhanced surface gusts and perhaps a
   short-lived tornado or two.

   ..Kerr.. 05/03/2020

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

   ATTN...WFO...LMK...OHX...PAH...MEG...LSX...LZK...SGF...

   LAT...LON   37509035 37438897 37218622 35888778 35549023 35539043
               35809181 36159248 36759152 37379128 37509035