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801
FXUS62 KCHS 170600
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
200 AM EDT Fri May 17 2024

.SYNOPSIS...
High pressure will persist into Friday. A storm system will
affect the area this weekend, followed by high pressure from
the north next week.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
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High pressure will prevail across the local area with a mid-lvl
ridge axis also placed across the Southeast United States in advance
of an MCS tracking across the Deep South. A fair amount of
radiational cooling will take place ahead of the MCS during the
night, resulting in calm winds and low temps that range in the low-
mid 60s inland to upper 60s/around 70 near the coast. However, mid-
high level clouds will likely increase from the west a few hours
prior to daybreak as the MCS presses eastward, limiting further
cooling potential. The decaying MCS will attempt to make way to far
inland zones around daybreak, but any shower/thunderstorm activity
will likely occur after 6 AM. As a result, a dry forecast will
remain through the remainder of the night.
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&&

.SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY/...
A potent shortwave will spread extensive mid and high clouds
over the area on Friday. Nevertheless, warm thicknesses should
support high temps pushing into the mid/upper 80s. Some drier
air is expected to mix down across inland areas with surface
dewpoints dropping into the lower 60s Friday afternoon. Much of
the guidance including synoptic scale models and CAMs show a
decaying MCS moving into our far western zones late Friday
afternoon. The best instability is forecast to remain just south
of the forecast area Friday afternoon/evening.

A warm front will lift north through the area Friday night, with
scattered showers and isolated thunderstorms possible through
the night. Saturday an increasing SW flow will bring >1.7"
PWATs into the area ahead of a longwave upper trough. There are
some hints that after warm frontal precipitation lifts north of
the area by mid Saturday morning, much of the day could be
relatively rain-free. A series of shortwaves will then move
through late Saturday afternoon through Saturday night, bringing
numerous to widespread showers and thunderstorms. The greatest
chance for severe thunderstorms will be Saturday afternoon
during which the strongest instability will be present. Most
guidance shows at least 1500 J/kg SBCAPE across the area and 50
kt bulk shear. This would support some storm organization with a
damaging wind threat. Forecast LIs <-7C would also support
large hail.

Plenty of moisture is expected to remain over the area through
Sunday as a cold front drops in from the NW, then the upper
trough axis swings through. Showers and thunderstorms are
likely to persist through the day. Isolated severe thunderstorms
could be possible due to decent instability ahead of the front.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
Isolated showers and thunderstorms will be possible through
Monday due to moisture and forcing on the western periphery of
the developing surface low off the NC/SC coast. Temperatures
will be considerably cooler due to cold advection as high
pressure builds from the north. The cooler weather will be
short-lived as the surface high shifts southeast and a southerly
flow redevelops. A few showers will be possible Wednesday as a
shortwave moves through.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
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VFR conditions are expected to prevail at CHS/JZI/SAV terminal
through 06Z Saturday. However, the remnants of an MCS will impact
the area, with the potential for SHRA/TSRA at the terminals (highest
chances at SAV). For now, VCSH remains in the TAF for SAV starting
around 15Z. Adjustments will likely be needed with later TAF
issuances to account for timing/occurrence of the event.

Extended Aviation Outlook: Showers and thunderstorms could bring
flight restrictions to all terminals Saturday through Sunday
as a low pressure system impacts the region.
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&&

.MARINE...
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Tonight: High pressure will remain across local waters resulting
in no marine concerns through daybreak. In general, south/southwest
winds will be around 10 kt or less. Seas will range between 1-2 ft.

Friday through Tuesday: Conditions through the period are
expected to remain below Small Craft Advisory criteria.
Southerly flow will persist through Sunday, then the winds turn
northerly behind a cold front early next week. Wind gusts could
approach 25 kt late Sunday night into Monday morning with an
initial burst of cold advection, mainly over the Charleston
County nearshore waters.
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&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...None.

&&

$$

NEAR TERM...DPB
SHORT TERM...JRL
LONG TERM...JRL
AVIATION...DPB
MARINE...DPB