645
FXUS62 KCHS 051810
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
210 PM EDT Sun Oct 5 2025

.SYNOPSIS...
Strong high pressure will extend across the region through mid-
week, with a cold front then progged to dive across the
southeastern CONUS heading into the weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
This evening and tonight: The morning heavy rainfall area is
still producing a pocket of moderate to heavy rain across Bryan
and Liberty counties but is definitely shrinking and weakening
as it shifts inland. This area will continue to push further
inland through the afternoon and we should end up with a period
of dry conditions through the mid to late afternoon hours.

Overall, the pattern remains unchanged with high pressure
parked to our north extending west and southwest across the Mid
Atlantic and into the Southern Appalachians. A coastal trough
will continue to sit just off our coast and model guidance
favors another round of showers developing across the coastal
waters late this evening and early Monday morning, then pushing
into the coast. Model guidance does not seem to be quite as
aggressive bringing in a large area of moderate to heavy
rainfall as it was for the forecast last night. But, we should
still see an expansion of showers and rain chances along the
coast late tonight and through sunrise Monday. The HREF doesn`t
have probabilities quite as high for an inch or more (~30%), but
we could still see some pockets of rainfall in the 0.25-0.50"
range. Expect another mild and humid night with lows only in the
upper 60s to low 70s.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
Upper level ridging gradually propagates eastward over the
Atlantic Monday, as a sfc high pressure lingers near the
Carolinas. Coastal trough also remains almost stationary along
our coast, keeping the stream of subtropical moisture advection
going. Thus, expect isolated to scattered showers to continue
offshore - with perhaps a few pushing inland throughout the
morning and early afternoon. Not expecting to see much in the
way of substantial rainfall - nonetheless, with the threat for
coastal flooding persisting, want to emphasize that any rain
occurring near the time of high tide could exacerbate flooding
impacts for very low lying coastal areas.

Should then see largely dry conditions prevail Tuesday and
Wednesday as the sfc ridge axis slides overhead. This will allow
for a brief reprieve in breezy northeasterly winds, especially
along the coast, with highs forecast to rise into the low to mid
80s under mostly sunny skies. May even see a few locations
across southeast interior Georgia take a shot at 90 degrees
Wednesday. Otherwise, look for lows in the mid to upper 60s to
remain common.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Sfc cold front extending from Maine to Texas is expected to
dive southeastward across the Ohio River Valley Wednesday night,
causing unsettled conditions to return to the forecast area by
Thursday. In terms of rainfall, overall moisture remains fairly
limited which should keep accumulations on the lighter side.

Of greater concern, will be the gusty northeasterly winds that
also return Thursday into Friday in the wake of FROPA. Could
easily see gusts along the coast range between 25 to 35 mph,
which, in addition to already elevated tide levels, could result
in a period of very impactful tidal flooding to end the week.
More on this in the coastal flooding section below.

Otherwise, model certainty decreases heading into next week, as
guidance diverges on how the upper level pattern will evolve.
For now, most models hints that an upper level low will develop
across the southeastern CONUS as the aforementioned front pushes
further into the Atlantic. However, a range in solutions still
exist concerning how far this low will sag, which will largely
determine how unsettled conditions become across our area.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
The 18z TAF period begins with VFR conditions in place at KCHS,
KJZI, and KSAV. Conditions should remain VFR through the
evening as well. The main forecast challenge revolves around the
potential for another round of showers to move onshore late
tonight at all 3 TAF sites, potentially bringing at least brief
periods of MVFR or even IFR conditions. Confidence isn`t as high
in seeing showers and restrictions as it was with the forecast
from yesterday afternoon, so we have only included VCSH at all 3
sites from roughly 08-15z. This potential will need further
refinement with the subsequent TAF issuances.

Extended Aviation Forecast: Lingering shower activity Monday
brings a limited threat for brief restrictions at all terminals.
Otherwise, no significant aviation impacts expected.

&&

.MARINE...
Tonight: The pattern will remain the same through the overnight
and will continue to favor east-northeast to east flow across
the local waters. Wind speeds should continue to sit in the
10-20 knot range, with gusts up to 25 knots at times. Seas will
continue to feature 4-6 feet across the nearshore waters and 5-8
feet across the outer waters. Small Craft Advisories remain in
effect for all waters outside Charleston Harbor.

Monday Onward: Very long fetch easterly winds will bring
persistent medium period swell across the waters, with some
underlying, but much smaller, longer period swell through early
week as well. The swell will peak Sunday night into Monday with
wave heights reaching 6-9 ft offshore, before only gradually
subsiding through midweek, when breezy NE winds will begin to
ease as well.

Rip Currents: A high risk of rip currents will continue through
Monday in primarily medium period E to NE swells.

&&

.TIDES/COASTAL FLOODING...
Upcoming evening high tide (~7:30 pm): Tide departures continue
to run very high and astronomical tide values will rise for the
upcoming evening high tide. Given recent trends in tidal
departures over the last several cycles, we should see
departures at high tide somewhere in the 1.2-1.4 ft range, which
will make minor to moderate coastal flooding almost certain.
The current forecast is for 7.6 ft MLLW at Charleston and 9.6 ft
MLLW at Fort Pulaski and a Coastal Flood Advisory has been
issued for the entire southeast SC and southeast GA coast.

Astronomical tides will continue to increase this week due to
the upcoming full moon (Oct 7) and perigee (Oct 8).
Additionally, tidal departure values will remain elevated with
periods of breezy NE winds this weekend through Monday, then
again Thursday into next weekend. As a result, the threat for
mainly minor to moderate coastal flooding with each high tide
cycles continues through mid-week. Then, late week, the threat
for major coastal flooding arrives with the late morning high
tides.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...High Risk for Rip Currents through Monday evening for GAZ117-119-
     139-141.
     Coastal Flood Advisory from 5 PM this afternoon to 10 PM EDT
     this evening for GAZ117-119-139-141.
SC...High Risk for Rip Currents through Monday evening for SCZ048>051.
     Coastal Flood Advisory from 5 PM this afternoon to 10 PM EDT
     this evening for SCZ048>051.
MARINE...Small Craft Advisory until 2 PM EDT Tuesday for AMZ350-352-354.
     Small Craft Advisory until 6 AM EDT Wednesday for AMZ374.

&&

$$

NEAR TERM...BSH
SHORT TERM...SST
LONG TERM...SST
AVIATION...BSH/SST
MARINE...BSH/SST