SPC Jul 10, 2020 0730 UTC Day 3 Severe Thunderstorm Outlook

SPC 0730Z Day 3 Outlook

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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from SPC Forecast Products http://www.spc.noaa.gov/products/outlook/day3otlk_0730.html