SPC AC 190724

   Day 3 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0224 AM CDT Mon Apr 19 2021

   Valid 211200Z - 221200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   THE MID-ATLANTIC...

   ...SUMMARY...
   Isolated strong to severe storms capable of producing mainly
   damaging winds may occur across parts of the Mid-Atlantic on
   Wednesday.

   ...Mid-Atlantic...
   Within large-scale upper troughing over the eastern CONUS, a
   shortwave trough is forecast to move quickly east-northeastward
   across the Mid-Atlantic and over New England on Wednesday. A surface
   low initially centered over PA should likewise develop northeastward
   into southern New England by Wednesday afternoon while deepening. An
   attendant cold front will sweep eastward across the Mid-Atlantic
   through the day. Modest low-level moisture return should occur ahead
   of this cold frontal passage, with low to mid 50s surface dewpoints
   possible per consensus of latest guidance. Diurnal heating across
   the warm sector should foster the development of weak instability by
   late Wednesday morning. Even though MLCAPE may only reach about
   250-500 J/kg ahead of the front, it should be sufficient to support
   surface-based storms. Current expectations are for a low-topped
   convective line to develop along the cold front by early Wednesday
   afternoon. These storms should move quickly eastward in tandem with
   the cold front, and off the Atlantic Coast by late afternoon or
   early evening. Given the forecast strength of the low/mid-level flow
   accompanying the shortwave trough, isolated strong to damaging wind
   gusts appear possible with this line where enough destabilization
   can occur.

   ...South Florida...
   A cold front should progress southward across this region through
   the period. Large-scale ascent and stronger mid-level flow
   associated with upper troughing over the eastern states is expected
   to remain well north of the southern FL Peninsula. Given that
   low-level winds are forecast to veer to westerly early in the
   period, convergence along the front will likely remain quite weak.
   Therefore, the potential for organized severe thunderstorms
   currently appears low.

   ..Gleason.. 04/19/2021

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   NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 0730Z