SPC AC 220442

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1042 PM CST Thu Dec 21 2017

   Valid 231200Z - 241200Z

   ...NO SEVERE THUNDERSTORM AREAS FORECAST...

   ...SUMMARY...
   Some thunderstorm potential will exist from the Mid-South into the
   Middle Atlantic region Saturday.

   ...Discussion...

   Strong short-wave trough over the southwestern US will eject across
   the southern Plains day1 then deamplify as it translates across the
   TN Valley into the Middle Atlantic by 24/00z. This feature will
   encourage a seasonally moist plume of modified Gulf air to stream
   across the mid-South ahead of a surging cold front. Latest
   short-range model guidance suggests significant large-scale forcing
   for ascent will spread ahead of the short wave where mid-level
   height falls are expected to focus. Forecast soundings exhibit
   modest mid-level lapse rates along a corridor from TN into the
   Delmarva which should contribute to adequate buoyancy for elevated
   convection. Updrafts will likely be rooted primarily near 850mb and
   the deepest convection could attain heights necessary for lightning
   discharge. For this reason have extended thunder probabilities into
   the Middle Atlantic where strongest forcing will be observed ahead
   of the short wave/surface low track.

   ..Darrow.. 12/22/2017

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   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z