SPC AC 100729

   Day 3 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0229 AM CDT Fri Jul 10 2020

   Valid 121200Z - 131200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PORTIONS OF
   THE SOUTHEAST INTO THE OHIO VALLEY...

   ...SUMMARY...
   Isolated severe thunderstorms will be possible on Sunday across
   portions of the Southeast into the Ohio Valley.

   ...Synopsis...
   Some dampening of the ridge across the Southwest into the southern
   Plains is expected on Sunday, as an upper trough deepens over the
   northwest/northern Rockies. Meanwhile, a broad upper trough is
   forecast to remain in place over the East. 

   ...Lower MS Valley into the TN/OH Valleys and Southeast...
   A broad region of modest midlevel northwesterly flow will be in
   place from portions of the MS Valley into the Southeast on Sunday.
   Evolution of convection on D2/Saturday (which remains quite
   uncertain) will influence the severe threat across this region later
   in the day. If sufficient destabilization can occur in the wake of
   any early convection, wind profiles will support some risk of
   organized convection, with a primary risk of locally damaging wind
   and perhaps some hail. 

   Further north into portions of the TN/OH Valleys, scattered
   thunderstorms are expected in closer proximity to the primary
   midlevel trough axis. The magnitude of instability with northward
   extent remains uncertain, but effective shear will likely support
   some threat for organized convection during the afternoon, with a
   corresponding risk of locally damaging wind and marginal hail. 

   ...Central/northern High Plains...
   Modest low-level moisture return into the central/northern High
   Plains may support at least isolated thunderstorm development Sunday
   afternoon. Wind profiles would conditionally support some organized
   convection, given sufficient instability. Uncertainty regarding the
   coverage of convection and magnitude of instability precludes the
   introduction of probabilities at this time. 

   ...Northern New England...
   The glancing influence of a departing shortwave trough may focus
   convection across portions of northern New England on Sunday. There
   is considerable model spread regarding the magnitude of instability
   across this region, but wind profiles would likely support some
   organized severe threat given sufficient buoyancy. Uncertainty
   remains too large at this forecast range to include probabilities
   with this forecast.

   ..Dean.. 07/10/2020

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