SPC Aug 15, 2020 0730 UTC Day 3 Severe Thunderstorm Outlook

SPC 0730Z Day 3 Outlook

Day 3 Convective Outlook  
NWS Storm Prediction Center Norman OK
0126 AM CDT Sat Aug 15 2020

Valid 171200Z - 181200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE OHIO
VALLEY/LOWER GREAT LAKES REGION AND VICINITY...

...SUMMARY...
Scattered afternoon and evening thunderstorms are expected across
the Ohio Valley and lower Great Lakes region, and eastward to the
New Jersey/New York coastal areas.  Locally strong wind gusts will
be the primary severe risk.

...Synopsis...
Little change to the large-scale flow field aloft will occur over
the U.S. Monday, as a large/strong ridge remains over the West,
while troughing persists over the East.  Within the eastern trough,
several smaller-scale disturbances will rotate eastward through the
broader belt of enhanced cyclonic flow.

At the surface, a weak front will cross the lower Great Lakes/Ohio
Valley region, while a weak baroclinic zone lingers west-to-east
along the Gulf Coast region.  Elsewhere, high pressure will largely
prevail.

...Ohio Valley/lower Great Lakes to the northern
Mid-Atlantic/western New England areas...
Multiple mid-level cyclonic disturbances are forecast to move
through the broader cyclonic flow field across the Great
Lakes/Northeast Monday, accompanied by a weak cool front expected to
be crossing the Ohio Valley and lower Great Lakes during the
afternoon and evening.  While lapse rates aloft will remain rather
weak, diurnal heating will contribute to modest destabilization --
sufficient to support development of widely scattered afternoon
storms.  

With moderate (generally 25 to 35 kt) mid-level westerlies across
this region, a few stronger storms/multicell clusters will likely
evolve, with occasional wind gusts capable of producing mainly tree
damage.  Storms will spread eastward with time, diminishing
gradually during the evening but with lingering/low-end severe risk
possibly reaching the NY/NJ coastal areas.

..Goss.. 08/15/2020

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