841
FXUS62 KCHS 172320
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
720 PM EDT Sun Aug 17 2025

.SYNOPSIS...
Weak high pressure will build into the region early this week
as Hurricane Erin passes well offshore through the middle of
the week. A cold front could drop into the area later in the
week.

&&

.NEAR TERM /THROUGH MONDAY/...
Tonight: Few to scattered showers/thunderstorms remain in the
forecast early evening, but the bulk of activity will likely
wane and/or dissipate within an hour or two post sunset. The
exception remains along the immediate Georgia coastline, where
an isolated shower/thunderstorm is possible overnight. Attention
turns over to fog potential late tonight. Winds are expected to
decouple this evening, remaining light/calm away from the coast
for much of the night. Additionally, skies should become
clear/mostly clear by late evening and persist for much of the
night. These conditions along with favorable condensation
pressure deficits suggest at the least some potential for patchy
fog to develop late tonight/early morning, especially across
Southern South Carolina into Southeast Georgia where saturated
grounds remain due to rainfall received during the past 24
hours. Overnight lows should generally range around 70 degrees
inland to mid 70s near the coast.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
The forecast area will largely stay on the eastern periphery of a
mid level ridge through mid week, with occasional weak vort maxes
poised to drop through the region. At the surface, a weak boundary
is expected to sink south into the area later Monday into Monday
night, allowing high pressure to build inland thereafter for Tuesday
and Wednesday. Meanwhile, powerful Hurricane Erin will track well
off the Southeast coast (its center forecast to stay ~500 miles to
the east). Convective coverage is not expected to be particularly
high on any given day, with just isolated to scattered showers and
thunderstorms highlighted in the forecast, mainly Tuesday and
Wednesday. Temperatures will be warmest on Monday with most areas
inland of the coast peaking in mid 90s. Heat indices will stay in
the 100-105 range. Highs settle closer to normal for Tuesday and
Wednesday. Lows will average in the low to mid 70s.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Hurricane Erin will quickly pull away from the region on Thursday.
As this occurs, a cold front will sink into the area and could
linger in the vicinity into late week or early weekend. While
isolated to perhaps scattered showers and thunderstorms are possible
Thursday, higher rain chances arrive Friday and Saturday as deep
moisture returns, and the front and mid level energy provide
potential forcing.

&&

.AVIATION /23Z SUNDAY THROUGH FRIDAY/...
Prior to the 0Z TAFs, KCLX detected a few dissipating showers
near KSAV. These showers should end before 0Z. The rest of the
night should feature dry conditions with light to calm winds. It
is possible that a period of ground fog or patchy fog may
develop near the terminals around dawn Monday, most likely at
KSAV. The fog potential is too uncertain to feature in the TAFs
at this time. On Monday, conditions appear less humid with
limited instability. All terminals are expected to remain free
of convection on Monday.

Extended Aviation Forecast: Brief flight restrictions are possible
in afternoon showers/thunderstorms Tuesday through late week.

&&

.MARINE...
This Afternoon and Tonight: Weak high pressure across local waters
will favor wind/sea conditions that remain well below Small Craft
Advisory levels. In general, east-northeast winds will remain 10-15
kt or less today, highest near the coast where a sea breeze occurs,
then turn more directly onshore (east), but weaken to 5-10 kt during
the night. Seas will generally range between 2-3 ft.

Monday through Friday: Attention for the week will be on Hurricane
Erin passing well off the Southeast Coast. Seas will really begin
building later Monday into mid-week, potentially peaking in the 8-11
foot range later Tuesday night through Wednesday. Winds also pick up
with some marginal 25 kt gusts possible through this period. Small
Craft Advisories have been issued for all coastal waters outside of
the Charleston Harbor, largely due to seas, beginning overnight
Monday. Hazardous seas will maintain Advisories through at least
Thursday, although they will start subsiding as Erin pulls away from
the region.

Rip Currents/High Surf: A period of dangerous beach conditions is
expected this week as Hurricane Erin passes well offshore.
Increasing long period swell will result in an enhanced risk of rip
currents at all area beaches, beginning Monday and continuing
through much of the week. A Moderate Risk is in place for Monday,
with a High Risk of rip currents forecast for Tuesday. In addition,
large breaking waves are expected, and a High Surf Advisory could be
needed towards mid week.

&&

.TIDES/COASTAL FLOODING...
Increased swell and elevated winds associated with Hurricane Erin
passing well offshore could cause higher tidal levels during the
middle of the week. At least minor coastal flooding is possible with
the evening high tide cycles as early as Tuesday. Coastal Flood
Advisories could be needed.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...Small Craft Advisory from 4 AM Tuesday to 8 PM EDT Thursday
     for AMZ350-352-354.
     Small Craft Advisory from midnight Monday night to 8 AM EDT
     Friday for AMZ374.

&&

$$

NEAR TERM...DPB
SHORT TERM...ETM
LONG TERM...ETM
AVIATION...NED
MARINE...DPB/ETM