SPC 1300Z Day 1 Outlook

Day 1 Outlook Image

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0700 AM CST Mon Nov 23 2020

Valid 231300Z - 241200Z


Although severe storms are not expected, scattered thunderstorms are
possible across portions of New England today and across parts of
the Rockies and Plains today and tonight.

...New England...
A shortwave trough/speed max over the Lower Great Lakes/Northeast
States will continue steadily eastward today. A strong southerly
low-level jet will continue to transport a modestly moist air mass
quickly northward into near-coastal areas early today in advance of
a cold front that will sweep eastward offshore this afternoon.
Numerous/steady bands of showers precede the cold front, with
embedded/scattered thunderstorms having become increasingly common
in the predawn hours off the coast of New Jersey/New York into
coastal southeast New England.

12Z observed soundings from OKX/New York City and CHH/Chatham MA
both sampled semi-steep mid-level lapse rates and weak buoyancy atop
a very shallow (less than 0.5 km AGL) stable boundary layer, with
235 J/kg MUCAPE (OKX) and 725 J/kg MUCAPE (CHH), respectively. 40-50
kt winds were noted within the lowest 1-2km AGL. A small
spatiotemporal opportunity exists mainly across near-coastal
southeast Massachusetts for some additional near-surface-rooted
destabilization this morning. Convectively aided strong wind gusts
cannot be entirely ruled out this morning, but the potential for
severe-caliber wind gusts is expected to remain low given the
probable persistence of boundary-layer stability over inland areas.

...Central/southern Rockies to Great Plains...
Considerable height falls will occur today and especially tonight in
association with a trough amplifying toward the Four Corners area,
with the exit region of a strengthening mid/high-level jet reaching
the south-central Plains tonight. Cooling mid-level profiles and
steepening lapse rates suggest some lightning potential with the
convection over the central/southern Rockies today into this
evening, with isolated thunderstorms also a possibility into nearby
parts of the Plains tonight.

..Guyer.. 11/23/2020

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