Subj : DAY1SVR: Day 1 Convective
To   : All
From : Mike Powell
Date : Thu Dec 28 2023 08:23:00

ACUS01 KWNS 281238
SWODY1
SPC AC 281237

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0637 AM CST Thu Dec 28 2023

Valid 281300Z - 291200Z

....NO SEVERE THUNDERSTORM AREAS FORECAST...

....SUMMARY...
No severe thunderstorms are forecast across the contiguous U.S.
through tonight.

....Synopsis/Discussion...
A large, long-lived, nearly stacked, mid/upper-level low is evident
in moisture-channel imagery over southern IL, with expansive
cyclonic flow still apparent from the central/southern Rockies to
the central/southern Appalachians, and the Great Lakes to the Gulf.
The 500-mb low should wobble erratically through the period while
taking a net eastward path up the lower Ohio Valley region.  Just
outside the southern rim of the gyre's closed isohypses, a couple
southern-stream shortwave troughs are apparent over the central and
southeastern Gulf.  In response, and along a surface boundary that
long has moved offshore from the Atlantic Coast, a frontal-wave low
was analyzed at 11Z over the western Straits of Florida, with a warm
front extending eastward, south of the Keys and across the Bahamas.

The low and front should remain just south of the Keys into early
afternoon, as the low ripples eastward to east-northeastward toward
the area between Bimini and Andros Island.  A small complex of
thunderstorms has been apparent for a few hours near the low, moving
eastward to the south of the Dry Tortugas and Marquesas Keys.  The
expanding northern fringes of this activity north of the low --
and/or additional convection developing in the warm-advection regime
farther downshear and north of the Straits boundary -- will pose
some lightning potential across the Keys and southernmost parts of
the peninsula through midday.  Around 100-300 J/kg elevated MUCAPE,
occasionally extending into icing layers suitable for lightning,
should be present north of the boundary, before the leading
shortwave trough passes.

...Edwards/Dean.. 12/28/2023

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