Mesoscale Discussion 0535
   NWS Storm Prediction Center Norman OK
   0621 PM CDT Mon May 04 2020

   Areas affected...Portions of central into middle Tennessee...far
   northeast Alabama...far northwest Georgia

   Concerning...Severe potential...Watch likely 

   Valid 042321Z - 050015Z

   Probability of Watch Issuance...95 percent

   SUMMARY...Organized quasi-linear convection continues to grow
   upscale, with relatively deep moisture and instability increasing
   ahead of the cluster. Bow echo development is possible with this
   convection, with damaging winds likely. Large hail will also be a
   concern, and given modest backing of the surface flow, a brief
   tornado cannot be ruled out. A downstream WW issuance will likely be
   needed.

   DISCUSSION...Strong linear segments, embedded within a larger region
   of convection, have produced 1-1.5 inch hail within the past couple
   of hours. KNQA WSR-88D data also suggests that some of these storm
   cores are hail/graupel laden, with up to 60 dBZ echoes noted over
   the -20C layer. In addition, latest RAP forecast soundings indicate
   a relatively dry, deep layer extending from 800-600 mb, suggesting
   that rapid cold pool development and expansion may accompany the
   aforementioned convection given adequate evaporative cooling of
   rainwater, supported by mid-level melting of frozen graupel/hail.

   Deep 925-850 mb moisture and steep mid-level lapse rates are both
   advecting northeastward ahead of the convection. Additional
   intensification of updrafts, and further evaporative cooling given
   the previously mentioned accompanying dry mid-level layer, will both
   serve to increase the damaging wind and large hail threat over the
   next few hours, as supported by the latest high-resolution model
   guidance. Given backed surface winds across portions of Middle
   Tennessee, a tornado or two may also occur. Severe potential is
   expected to continue downstream of WW 0164 as storm mergers and
   upscale growth continues, with a WW issuance expected shortly.

   ..Squitieri.. 05/04/2020

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

   ATTN...WFO...MRX...FFC...OHX...HUN...PAH...MEG...

   LAT...LON   35689022 36049035 36379008 36668961 36798930 36698862
               36568790 35798576 35238462 34868472 34698485 34558546
               34528609 34678700 34978787 35348961 35689022