SPC 1300Z Day 1 Outlook

Day 1 Outlook Image

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0700 AM CST Sun Nov 22 2020

Valid 221300Z - 231200Z


Organized severe thunderstorms are not expected across the U.S.
today or tonight.

A strong shortwave trough is forecast to move from the
central/northern Plains this morning quickly eastward to the lower
Great Lakes region by 12Z Monday. In conjunction with this feature,
a weak surface low will slowly deepen and move northeastward from
the Ohio Valley this morning into portions of New England by Monday
morning. Upstream, another mid/upper-level trough will deepen over
the western CONUS tonight.

Thunderstorm potential is expected to increase this evening into the
overnight across the eastern Carolinas, as moisture and instability
gradually increase ahead of the quickly approaching upstream
shortwave trough and cold front. Thunderstorms across inland areas
are expected to remain elevated, though surface-based convection
cannot be entirely ruled out near the Outer Banks. At this time, the
best potential for stronger and more organized storms tonight is
expected to remain offshore.

...New England...
Late tonight into early Monday morning, a southerly low-level jet
will advect richer Atlantic low-level moisture into portions of
southern New England. Some convection is likely to develop within a
warm-advection regime, with a few lightning strikes possible in
conjunction with the strongest updrafts. While some stronger gusts
cannot be entirely ruled out, convection is expected to generally
remain disorganized through 12Z Monday, with the cold front not
expected to move through the region until later in the day Monday. 

...Southern Plains to the Tennessee Valley...
West/east bands of convection will persist today from southern
Oklahoma/north Texas into Arkansas and parts of Tennessee and
Kentucky. Occasional lightning flashes will remain possible this
morning, but overall convective intensity will otherwise wane with
diminishing thunderstorm potential into the afternoon.

Periodic bouts of weak convection may be capable of a few lightning
flashes across mainly the eastern part of the Florida Peninsula
today, though most showers will struggle to deepen due to the
presence of dry air aloft and lack of large-scale ascent across the

...Western Colorado/Northwest New Mexico...
As the mid/upper-level trough deepens over the West, gradually
increasing moisture and instability may support convection capable
of sporadic lightning activity across portions of northwest
New Mexico/western Colorado tonight.

..Guyer.. 11/22/2020

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