732
FXUS62 KCHS 061051
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
651 AM EDT Sat Sep 6 2025

.SYNOPSIS...
High pressure will extend across our area today. A cold front
is expected to move through late Sunday. The front should stall
offshore through the middle of next week, while High pressure
prevails to our north.

&&

.NEAR TERM /THROUGH TONIGHT/...
Atlantic surface high pressure off to our east is is leading to
mostly quiet conditions across the region, with radiational cooling
resulting in overnight lows this morning in the upper 60s inland to
lower 70s along the coast. Given the strong temperature inversion
near the surface, would not be surprised to see some patchy fog
develop prior to daybreak, though low-level condensation pressure
deficits remain fairly high which should help keep visibilities
from dropping below 1 mile. NBM probabilities for visibilities
below 1 mile are highest near the CSRA right around 30%, though
some patchy and shallow ground fog will likely be seen across
the region in low- lying areas.

The inversion will be slow to mix out throughout the morning, but
once it does temperatures will quickly rise back into the 80s by the
mid-morning hours and 90s into the early afternoon. While the region
does remain out ahead of the trough axis aloft, the expected sea-
breeze likely won`t be enough to develop any showers/storms given
that k-index values remain below 30 for most of the day. Otherwise,
we`ll be watching a cold front move towards the area from west-
northwest, likely reaching our extreme west prior to daybreak
Sunday. Some models are hinting at chances for fog again during the
overnight period into Sunday, though given the expected additional
cloud coverage aloft, mention of fog was left out of the
forecast.

&&

.SHORT TERM /SUNDAY THROUGH TUESDAY/...
Sunday: The mid-levels will consist of a trough stretching from the
Great Lakes region into the Deep South in the morning. It`ll slowly
lift northeast as time progresses. At the surface, a cold front will
be located to our northwest in the morning. There are some
differences between the models regarding how quickly it moves
through our area. But the consensus seems to have it pushing
southeast through our area in the afternoon or evening, then well
offshore overnight. There is a decent plume of moisture ahead of the
front, with PWATs peaking ~1.75" late. High temperatures should peak
in the upper 80s to lower 90s, except cooler at the beaches. Even
with this heat and moisture, models don`t have much instability in
place. So even though thunderstorms are in the forecast, the risk of
strong to severe storms is very low. Though, locally heavy rainfall
is possible in a few spots. Otherwise, the NBM has chance POPs in
the afternoon and early evening, with drier conditions inland behind
the front. Slight chance to chance POPs could persist along the
immediate coast late at night. Lows should range from the mid 60s
far inland to the lower 70s near the beaches.

Monday and Tuesday: Weak mid-level troughing should prevail over the
Southeast U.S. Though, it could strengthen on Tuesday in response to
an approaching ridge from the Central Plains. At the surface, a cold
front will be moving offshore Monday morning, then transition to a
stationary front to our south and southeast through Tuesday.
Meanwhile, High pressure should stay centered over New England both
days. The periphery of the High should stretch all the way down into
the Southeast U.S. This synoptic setup should yield a tight gradient
between dry conditions and rainfall. The NBM has the lowest POPs and
QPF far inland, with the highest POPs and QPF along the immediate
coast. Even higher POPs are further offshore. Though, it`s possible
the NBM is too high with both the POPs and the QPF. High
temperatures will be below normal due to the persistent clouds and
gusty northeast winds, especially along the immediate coast. Highs
should range from the low/mid 70s across our SC counties, to the
low/mid 80s across our GA counties.

&&

.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
The surface pattern should feature a wedge of High pressure to our
north and inland with a stationary front well to our south and
southeast. The NBM keeps slight chance to chance POPs closer to the
coast each day. Temperatures should remain a few degrees below
normal.

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
12 TAFs - Patchy MVFR fog is occuring across portions of the area,
with some isolated IFR visbys as well...though the three TAF sites
have managed to stay clear of the fog. SAV looks to just be
across the river from a bank of fog so will maintain a tempo 4
sm group, with otherwise a VFR day expected once the fog burns
off. Winds slowly increase while remaining light and out of the
south-southeast by late afternoon. Can`t entirely rule out the
possibility of fog again into Sunday, though the increase cloud
coverage continues probabilities just below 50%.

Extended Aviation Forecast: A cold front could bring some flight
restrictions due to showers Sunday afternoon. Additional flight
restrictions are possible from showers each afternoon through
Wednesday.

&&

.MARINE...
Quiet conditions will continue today as a front approaches from
the west. Light northeasterly winds this morning will turn south-
southeasterly into the afternoon hours, with seas remaining
between 2-3 ft.

Extended Marine: A cold front will approach from the northwest on
Sunday, then move across the waters by Sunday night. The front
should stall offshore through the middle of next week, while High
pressure prevails to our north. This synoptic setup will cause
northeast winds to surge behind the front and stay elevated through
the middle of next week. Small Craft Advisories will be needed for
all of our ocean waters during this time period for winds and seas,
and perhaps for the Charleston Harbor due to winds. Conditions
should start to improve on Wednesday, with winds and seas trending
lower.

&&

.TIDES/COASTAL FLOODING...
Astronomical tide levels will continue to increase through the
weekend, getting as high as 6.4 ft MLLW by the Sunday evening
high tide cycle within the Charleston Harbor. However, winds
will not be particularly favorable for large tidal departures
during this time period but observed peak tides could still top
out around 7 ft MLLW at Charleston each evening through Sunday.

Astronomical tide levels will remain high through the middle of
next week, given a full moon (9/7) and lunar perigee (9/10). A
notable surge of northeast flow along the coast is expected to
produce increased tidal departures through at least the middle
of next week which will result in an increasing probability of
minor to moderate coastal flooding along portions of the SC
coast. Minor coastal flooding is possible along the lower SC and
GA coast beginning Monday evening.

&&

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

&&

$$

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