SPC Dec 10, 2023 0600 UTC Day 1 Convective Outlook

[NorthGeorgiaWX]

SPC 1200Z Day 1 Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1159 PM CST Sat Dec 09 2023

Valid 101200Z - 111200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
FAR EASTERN SOUTH CAROLINA AND EASTERN NORTH CAROLINA...

...SUMMARY...
Severe thunderstorms associated with wind damage and a few tornadoes
are expected across parts of far eastern South Carolina and eastern
North Carolina today. Marginally severe wind gusts will also be
possible over much of the Atlantic Coastal region from Florida to
the Mid-Atlantic.

...Atlantic Coastal States...
An upper-level trough will move eastward across the Ohio and
Tennessee Valleys today, as an associated belt of strong mid-level
flow translates eastward into the Appalachians and Atlantic coastal
states. At the surface, a cold front will advance eastward through
the southern and central Appalachians. Ahead of the front, moisture
advection will take place from the eastern Gulf Coast States
northward to the Mid-Atlantic, maintaining or increasing surface
dewpoints into the lower to mid 60s F in most areas. Thunderstorms
are expected to continue throughout the morning as the front
progresses eastward. Strengthening low-level flow ahead of the
system will result in a gradual increase in convective coverage
throughout the day over the moist sector. In spite of abundant cloud
cover and weak instability, an isolated severe threat is expected to
develop ahead of the front. Marginally severe wind gusts will be the
primary threat from northern Florida northward into the western and
central Carolinas and into the Mid-Atlantic.

Over the eastern Carolinas, the severe threat is expected to be
greater due to a number of factors. First, model forecasts suggest
that a corridor of stronger instability will develop by afternoon
from far eastern South Carolina into east-central North Carolina,
where MLCAPE is expected to peak around 1000 J/kg. Second, a
low-level jet is forecast to move through the central Carolinas
during the early afternoon. The combination of stronger instability,
moderate to strong deep-layer shear and increasing low-level flow
will be favorable for rotating storms. As the low-level jet moves
through during the early afternoon, 0-3 km storm-relative helicity
is forecast to increase to around 200 m2/s2 over parts of far
eastern South Carolina and eastern North Carolina, suggesting that
some of the storms could develop a tornado threat. The tornado
threat will likely be greatest with storms that remain discrete and
develop near the moist axis. A gradual increase in storm coverage is
expected during afternoon, with a mixed mode likely. Supercells and
organized line segments will likely be capable of wind-damage, with
the threat peaking during the early to mid afternoon.

..Broyles/Wendt.. 12/10/2023

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