Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point. Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
SPC AC 071743
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1243 PM CDT Tue Sep 07 2021
Valid 081200Z - 091200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF
EASTERN NEW YORK AND PENNSYLVANIA INTO NORTHERN NEW JERSEY...
Scattered strong to severe thunderstorms are expected across parts
of the Northeast and Mid Atlantic Wednesday afternoon and evening.
...Mid Atlantic into the Northeast...
An amplified upper air pattern will exist on Wednesday with a
prominent high over the Four Corners states and a deep upper trough
moving from the Great Lakes into the Northeast.
At the surface, a low is forecast to pivot from eastern Ontario into
western Quebec, with a cold front extending south across central NY
into eastern PA by late afternoon. Southerly surface winds will
result in a northward advection of mid to possibly upper 60s F
dewpoints from the Delmarva into NJ and possibly southeast PA.
Low-level lapse rates will be steepest across WV/VA, with best
overall theta-e from MD into eastern PA. Southerly 850 mb winds
around 40 kt will aid SRH with effective values over 200 m2/s2 by
While hodographs will be favorable for rotating storms, one
mitigating factor may be the warm layer near 700 mb which may
negatively impact low-level buoyancy. That said, lift along the
front may be deep enough to support a supercell threat, and a brief
tornado or two will be possible. Scattered damaging gusts are
expected as storms become linear along the front. Good CAM agreement
exists with increasing storms between 21-00Z from eastern NY into
eastern PA, with maximum storm coverage just after 00Z. The loss of
heating will play a part in limiting the eastward extent of the
Farther south into VA and NC, ample buoyancy will exist but with
marginal shear. Both marginal hail and wind gusts will be possible
after 21Z, with storms most likely from southern VA into central NC.
Winds aloft will be quite a bit weaker farther southwest into SC and
GA, but storms will also be likely near a surface trough. A few
strong wind gusts cannot be ruled out with activity that forms in
this region during the late afternoon, but the severe risk appears
limited due to weak lapse rates aloft as well as shear.
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NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0600Z