Day: March 17, 2018

   Mesoscale Discussion 0127
   NWS Storm Prediction Center Norman OK
   0225 PM CDT Sat Mar 17 2018

   Areas affected...Central and Southeast KY...Northeast TN...Extreme
   Southwest VA

   Concerning...Severe potential...Watch likely 

   Valid 171925Z - 172130Z

   Probability of Watch Issuance...80 percent

   SUMMARY...Scattered thunderstorms are expected to form over central
   KY this afternoon, spreading/developing east-southeastward into
   adjacent parts of TN and VA.  Large hail will be possible in the
   stronger cells.  A watch is likely in the next couple of hours.

   DISCUSSION...Visible satellite loops show a corridor of increasing
   cumulus development over north-central KY.  This is in vicinity of a
   weak surface low that will track southeastward across the discussion
   area during the afternoon and early evening.  Strong heating is
   occurring in the warm sector of the low, resulting in substantial
   heating and destabilization.  Meanwhile, low-level moisture is
   slowly returning to this area with dewpoints now in the 50s.

   Present indications are that storms will initiate near the surface
   low in the next 1-2 hours and spread southeastward across parts of
   southeast KY and into northeast TN and western VA.  Sufficient CAPE
   and favorable effective shear/mid-level lapse rates will promote
   rotating cells capable of large hail.  Locally damaging winds may
   also occur if storms can congeal and develop upscale several hours
   from now.

   ..Hart/Guyer.. 03/17/2018