006
FXUS62 KCHS 242346
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
746 PM EDT Sun Aug 24 2025

.SYNOPSIS...
Low pressure will pull away from the area tonight. A cold front
will clear the area Monday night with high pressure prevailing
through much of the week.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Drier air delineated by much lower PWATs compared to the past
few weeks will settle into the area tonight as low pressure
offshore pulls farther away from the region. Guidance still
depicts a pocket of considerably lower 850 hPa theta-e dropping
into much of the Lowcountry and Southeast Georgia as mid-level
dry air expands. This is also reflected in RAP soundings where
only meager instability will develop by peak heating even as the
cloud canopy thins. This should keep any convection that can
fire limited in coverage. Pops 10-20% were maintained with
decreasing cloudiness continuing as some downslope component
takes shape while the 850-700 hPa flow backs with time.

Dry conditions will prevail overnight, although weak troughiness
will linger in the wake of departing low pressure. Mostly clear
skies and diminishing winds will promote some degree of
radiational cooling, although some thin high clouds will
persist. Lows will range from the upper 60s/lower 70s inland
to the mid-upper 70s at the beaches. Some shallow ground fog
could develop in spots prior to daybreak Monday, but high 1000
hPa condensation pressure deficits suggest any fog that forms
not to become too widespread or significant.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
A digging upper level trough will be situated along the east
coast on Monday, with our previous surface frontal boundary
situated well off to our northeast. However, a separate cold
front attached to the surface low pressure near Hudson Bay is
also moving towards to the area from the west, with remnant
warmth and moisture keeping highs in the lower 90s and dewpoints
in the lower to mid 70s for most. While up to 3000 J/kg of
MUCAPE develops throughout the day (MLCAPE is much lower at
below 1000 J/kg) the vast majority of guidance keeps the area
dry as lifting mechanisms are too weak to overcome the synoptic
scale descent in the vicinity of the upper right exit region of
the upper level jet.

For Tuesday, the trough axis still hasn`t swept through the
region yet, keeping the main cold front off to our west out
ahead of a surface high pressure over the Ohio River Valley. Dry
conditions are expected as cooler (highs in the mid to upper
80s) and drier air (dewpoints in the 60s!) filters into the
area.

By Wednesday morning, the main cold front will have been pushed
through as the main wave moves through the upper level trough
axis. Benign conditions expected throughout the day as the
surface high pressure sets up to our north-northwest and weak
ridging develops aloft out ahead of our next approaching
shortwave.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Broad high pressure will remain over central Appalachian, with
the forecast area located within its southeastern fringes into
the weekend. This will result in mostly cooler conditions (daily
highs in the 80s and dewpoints in the 60s), though a shortwave
looks to pass across the area sometime later this week resulting
in an unsettled period. Ensemble clustering analysis does
little to help with uncertainty as clusters are relatively
evenly split, even within each respective group of ensembles.
Project EAGLE would suggest a low passing risk for southeastern
Georgia on Thursday night and again Friday as it brings the
surface high pressure further south along the eastern seaboard,
while its ensemble brings chances for rain further north in-line
with other ensembles, including the NBM.

&&

.AVIATION /00Z MONDAY THROUGH FRIDAY/...
VFR conditions will prevail at CHS/JZI/SAV terminals through 00Z
Tuesday.

Extended Aviation Forecast: There may be some very scattered
convection across southeastern Georgia on Monday, capable of
producing brief flight restrictions. Otherwise, concerns are low
for flight restrictions into the end of the week.

&&

.MARINE...
Tonight: Winds are expected to turn southerly this evening, then
westerly late as a cold front approaches Monday. Speeds will
remain less than 15 kt while seas ranging between 2-4 ft gradually
subside about 1 ft through the night.

Monday through Friday: South-southwesterly winds during the day
Monday will shift out of the northeast overnight as a cold
front pushes offshore. Both winds and seas look to remain below
Small Craft Advisory levels both during and after FROPA.
Northeast winds will prevail through the remainder of the period
with no marine concerns outside of shower and thunderstorm
activity.

&&

.TIDES/COASTAL FLOODING...
River and creek levels remain elevated following heavy rainfall
on Friday and Saturday and salinity levels upstream of the
representative tide gages have decreased in response to the
heavy storm freshwater input. High river levels/discharge should
remain through the evening, keeping tidal departures near 1.5 ft
at the Charleston Harbor during peak high tide. A Coastal Flood
Advisory has been issued for Charleston and Coastal Colleton
Counties from 8 PM to 12 AM, with minor coastal flooding likely
to occur 1-2 hours before/after the high tide this evening (9:43
PM). There is a low risk for moderate coastal flooding for a
shorter time should departures reach 1.6 ft at the peak of the
event.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...Coastal Flood Advisory until midnight EDT tonight for SCZ049-
     050.
MARINE...None.

&&

$$

NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...