817
FXUS62 KCHS 080650
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
250 AM EDT Wed Oct 8 2025

.SYNOPSIS...
High pressure will persist across the region today. A cold
front will drop south through the area tonight into Thursday
with inland high pressure prevailing into early next week. Low
pressure will develop off the Southeast U.S. coast this
weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
Prior to Daybreak: Weak sfc high pressure will remain across the
local area under ridge axis stretched across the region through
daybreak. Light/calm winds under mostly clear skies continues to
favor radiational cooling, while condensation pressure deficits and
low-lvl moisture suggest patchy to areas of fog developing across
much of the area away from the beaches prior to daybreak. Latest
guidance, particularly the HREF indicates the potential for some fog
to become dense, especially across inland areas and perhaps with
some greater coverage for locations that saw rain during the
previous day. Vsbys lowering to the 1/2 to 1 mile range are most
probable for a 3-5 hr stretch around daybreak. Conditions will
continue to be monitored for potentially lower vsbys and the need
for a Special Weather Statement and/or Dense Fog Advisory. Low temps
should range in the mid 60s inland to upper 60s/lower 70s closer to
the coast.

Today: Aloft, mid-upper lvl ridging will remain stretched across
region from the northeast Gulf Coast to the western Atlantic ahead
of a large trough advancing across the Great Lakes region to the
Northeast and Mid-Atlantic states by mid-late afternoon. The trough
will help advance a cold front toward the region, but the front will
remain west of the local area through daylight hours. Ahead of this
feature, weak high pressure will hold across the local area under
the ridge axis aloft, supporting warmer temps across Southeast South
Carolina and Southeast Georgia within a light east-southeast flow.
In general, high temps should peak in the mid-upper 80s, warmest
across the Georgia interior. A few spots could even touch 90 well
inland in this area. Initial h5 vort energy associated with the mid-
upper lvl trough arrives mid afternoon, and given ample heating and
a stretch of PWATs approaching 2 inches should favor few to perhaps
scattered showers/thunderstorms across areas well inland prior to
sunset.

Tonight: A cold front will approach from the northwest, nudging a
few to scattered showers and thunderstorms toward the coast during
evening hours. Fropa should be slow to occur during the overnight,
becoming further displaced from the mid-upper lvl trough passing
across the Northeast and offshore. Sfc winds will flip to the
northeast after midnight as high pressure builds in wake of the
front, leading to breezy conditions late as the pressure gradient
tightens and cold air advection takes place. Timing of the front
along with cold air advection will be key to how gusty winds are
able to get prior to daybreak, which could lead to a Lake Wind
Advisory across Lake Moultrie starting around daybreak. Temps will
remain mild prior to fropa, but eventually dip into the low-mid 60s
after midnight.

&&

.SHORT TERM /THURSDAY THROUGH SATURDAY/...
In the wake of a cold front high pressure will build into the region
on Thursday morning, centered over New England. Aloft, the region
will remain in the southern periphery of large scale troughing over
the eastern CONUS. Some lingering showers post-FROPA are possible,
mainly along the southeastern GA coastline. Otherwise, most other
areas will remain rain free. The cold front will usher in a cooler
airmass, with temperatures Thursday forecast to only reach into the
low to mid 70s, with a steady NE wind gusting to around 20 mph in
the afternoon. Gusts will be higher along the direct coastline.
Overnight lows will drop into the mid 50s far inland, with around 60
along the coastal counties.

An upper low will develop over the southeastern states Friday and
into Saturday. In association with this upper low, surface
cyclogenesis is expected off the southeastern coast. A wedge of high
pressure will remain in place over the local forecast areas. There
is a chance of rain mainly along the coastline Friday and Saturday,
however the rainfall will likely be dependent on the position of
cyclogenesis off the coast. With the region pinched between the high
pressure inland and the cyclogenesis offshore breezy conditions will
prevail over the area, strongest along the beaches. High
temperatures in the low to mid 70s Friday will warm into the mid to
upper 70s on Saturday. Overnight lows will be in the 50s inland and
60s near the coast.

Lake Winds: Winds on Lake Moultrie will become elevated early
Thursday morning and into the weekend as a strong, pinched gradient
develops in response to building high pressure across the region and
cyclogenesis off the coast. Winds look to reach Lake Wind Advisory
level criteria (sustained 20 kt or frequent gusts to 25 kt) during
this time and a Lake Wind Advisory will likely be required.

&&

.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
The region will be under the influence of cyclonic flow aloft
centered over the Mid-Atlantic. High pressure will prevail at the
surface, reinforced by the cyclonic flow aloft. A rain-free forecast
has been maintained through the period. Temperatures will slowly
warm to slightly above normal by the middle of next week.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
Latest obs are indicating some reduced vsbys associated fog
developing across the region. MVFR groups with BCFG start out around
09Z at CHS/JZI terminals and 06Z at SAV. There is some suggestion in
guidance that fog and low cigs could occur from 09Z-13Z at all
terminals. For this reason, TEMPO IFR groups remain at all sites for
cigs, with reduced vsbys also approaching 1/2SM at SAV. VFR
conditions should then prevail late morning and through the
afternoon, prior to a cold front approaching the area overnight.
TEMPO MVFR groups could eventually be needed for showers after 00Z
Thursday. For now, VCSH has been included at CHS/JZI terminals. SAV
remains VFR through 06Z Thursday.

Extended Aviation Outlook: Gusty N to NE winds will impact
KCHS/KJZI/KSAV Thursday and Friday, possibly lingering into the
weekend as high pressure builds over the region.

&&

.MARINE...
Today and Tonight: Weak high pressure will prevail across local
waters for much of the day well ahead of a cold front arriving
overnight. Once fropa occurs, conditions are expected to deteriorate
late night, with winds increasing and seas building as strong high
pressure builds in wake of the front and cold air advection begins.
During the day, easterly winds will be no higher than 5-10 kt with
seas 3-4 ft across nearshore waters and 4-5 ft across outer Georgia
waters. Overnight, winds become northeasterly, increasing to 15-20
kt after midnight. Gusts around 25 kt begin across nearshore waters
off the Charleston County Coast late, but seas will initially be
slow to build across remaining waters until after daybreak. A Small
Craft Advisory has been issued for nearshore waters off Charleston
County at 5 AM, with remaining waters following at 8 AM.

Thursday through Monday: A cold front will push into the marine
waters Thursday morning, bringing rapidly deteriorating marine
conditions as high pressure builds across inland zones and low
pressure develops off the southeast coast. NE winds will increase to
20 to 25 knots Thursday morning, with seas 4 to 5 ft across the
nearshore waters and 5 to 6 ft in the 20 to 60 nm offshore GA
waters. A Small Craft Advisory has been issued for all waters
including the Charleston Harbor starting Thursday morning. Winds are
expected to continue to increase into the afternoon hours, with
gusts approaching 35 knots. A Gale Watch has been issued for all
waters outside of the Charleston Harbor through the weekend. Due to
the low pressure development off the southeast coast seas will build
into the weekend, peaking Friday night into Saturday with 8 to 10ft
in the nearshore waters and up to 12 ft in the 20 to 60 nm offshore
GA waters. As the low pressure departs to the northeast and high
pressure begins to weaken inland conditions will begin to improve on
Monday, however 25 knot wind gusts could linger across the marine
zones.

Rip Currents: A lingering 8-9 sec swell will keep the rip current
risk into the moderate range for all beaches today. A blend of the
latest rip current MOS with local rip current calculations support
a high risk of rip currents at all area beaches on Friday. An
enhanced risk of rip currents will persist into the weekend due
to building surf and increasing winds associated with the building
high pressure.

High Surf: The risk for high surf will increase Thursday night into
the start of the weekend as wave heights increase across the local
waters. A High Surf Advisory may be required for some area beaches.

&&

.TIDES/COASTAL FLOODING...
Wednesday morning high tides: Based on recent tidal trend departures,
tide levels were increased to 7.7 ft MLLW at Charleston Harbor
and 9.8 ft MLLW at Fort Pulaski, GA. Coastal Flood Advisories
are in effect from 7 to 11 AM for Charleston and coastal Colleton
Counties and 8 to 11 AM from Beaufort south to McIntosh County.

Astronomical tides will continue to increase this week due to the
full moon today (Oct 7) and perigee (Oct 8). Additionally, tidal
departure values will begin to increase again late week and into the
weekend due to strong NE winds. As a result, the threat for minor to
moderate coastal flooding continues through mid-week. Late week the
threat for major coastal flooding arrives for the late morning high
tides.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...Coastal Flood Advisory from 8 AM to 11 AM EDT this morning for
     GAZ117-119-139-141.
SC...Coastal Flood Advisory from 8 AM to 11 AM EDT this morning for
     SCZ048-051.
     Coastal Flood Advisory from 7 AM to 11 AM EDT this morning for
     SCZ049-050.
MARINE...Small Craft Advisory from 8 AM Thursday to 6 AM EDT Sunday for
     AMZ330.
     Small Craft Advisory from 5 AM to 2 PM EDT Thursday for AMZ350.
     Gale Watch from Thursday afternoon through late Saturday night
     for AMZ350.
     Small Craft Advisory from 8 AM to 2 PM EDT Thursday for AMZ352-
     354-374.
     Gale Watch from Thursday afternoon through Saturday evening
     for AMZ352.
     Gale Watch from Thursday afternoon through Saturday afternoon
     for AMZ354.
     Gale Watch from Thursday afternoon through Sunday morning for
     AMZ374.

&&

$$

NEAR TERM...DPB
SHORT TERM...CPM
LONG TERM...CPM
AVIATION...CPM/DPB
MARINE...CPM/DPB