ACUS01 KWNS 281300
SWODY1
SPC AC 281259

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0659 AM CST Wed Feb 28 2024

Valid 281300Z - 291200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE
APPALACHIAN STATES...AND EASTWARD TO THE EASTERN U.S. COASTAL
PLAIN...

...SUMMARY...
Isolated strong to severe gusts will be possible today from the west
slopes of the Appalachians to western New England, the Mid-Atlantic
Region, and portions of the Carolinas.

...Synopsis...
Mid-level troughing over the central U.S. this morning will continue
to intensify as it gradually takes on a more negative tilt, shifting
eastward across the eastern third of the U.S. through tonight.
Meanwhile, weak ridging will generally prevail over the West, ahead
of second trough over the Gulf of Alaska digging southeastward
toward the Pacific Northwest.

At the surface, a strong cold front will cross the Appalachians
through midday, and then continue across the eastern U.S., with the
boundary moving off the Atlantic and Gulf Coasts this evening and
lingering only across Florida overnight. In the West, a cold front
will gradually shift southeastward into/across the Pacific
Northwest. In between, high pressure will prevail across much of
the country.

...Appalachian states...
Showers and thunderstorms are ongoing this morning from the Lower
Great Lakes region southwestward to the Mississippi Delta, along and
ahead of the advancing cold front. The strongest storms are ongoing
from the Upper Ohio Valley southwestward across Kentucky, where
occasionally severe storms -- capable of producing damaging wind
gusts and a brief tornado or two -- continue moving eastward.

Instability ahead of the convection weakens with eastward extent,
particularly east of the mountains. However, pockets of
near-surface-based CAPE in the 250 to 500 J/kg range will be
possible through this afternoon -- enough to support broken/narrow
frontal convective bands until the front moves offshore this
evening.

Despite the very weak instability, the deep-layer wind field will
remain particularly strong -- including 40 to 60 kt as low as 1km
AGL and increasing with height. As such, potential for convectively
enhanced mixing/downward momentum transport appears to be sufficient
to suggest the possibility if isolated severe-caliber wind gusts.
This warrants eastward expansion of 5% wind probability/MRGL risk
through the day, with risk ending as the front moves offshore this
evening.

..Goss/Broyles.. 02/28/2024

$$
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