157
FXUS62 KCHS 310650
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
250 AM EDT Sun Aug 31 2025

.SYNOPSIS...
High pressure will extend across the area through mid week
while a stationary front lingers just off the coast. A cold
front will move through Thursday night or Friday.

&&

.NEAR TERM /THROUGH TONIGHT/...
Today: Aloft, mid-lvl troughing extending from the Northeast to
Southeast United States will attempt to become cutoff across the Mid-
Atlantic states by this evening, favoring subtle/weak shortwave
energy to traverse the region throughout much of the day. At the
sfc, low pressure will continue to pull further offshore and away
from the local area, allowing high pressure to build inland
throughout the afternoon. A weaker boundary associated with this
airmass should remain closer/stall near the coast, currently
depicted on radar imagery just off the South Carolina beaches. This
boundary should become the primary focus in regards to potential
shower and/or thunderstorm activity developing nearby late morning
into early afternoon, with activity potentially shifting back
onshore within a low-lvl northeast flow. However, the environment is
quite different in regards to deep moisture compared to yesterday
(PWATs now between 1.25 to 1.50 inches), with water vapor imagery
also indicating a fairly substantial amount of dry air across the
local area in the mid-lvls, which is also depicted in local
soundings. This should tend to favor any convection struggling to
persist if drifting onshore, and likely lead to much lower rainfall
amounts than experienced the previous day, generally under 1/4 inch
near the coast. Additionally, the pressure gradient will strengthen
between high pressure inland and low pressure offshore, setting up
breezy northeast winds along the coastal corridor. Gusts should
generally top out near 20-30 mph this afternoon.

Despite high pressure building across the area and north-northeast
winds prevailing for much of the day, the lack of precip and lack of
significant cloud cover should lead to warmer temps compared to the
previous day, with highs generally peaking in the low-mid 80s,
warmest across Southeast Georgia away from the coast.

Tonight: Any convection able to develop near coastal areas during
the day will quickly come to an end with the loss of daytime
heating. The mid-upper lvl low becomes more cutoff while high
pressure prevails across the Southeast through the night. The
pattern favors dry and cooler conditions for all areas as light
northeasterly winds occur for a bulk of the night. Low temps should
generally range in the lower 60s inland to mid-upper 60s closer to
the coast.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
Cool and dry high pressure north of the region will continue to
ridge down the Eastern Seaboard Monday and Tuesday, maintaining
a relatively dry airmass over the area with temps below normal.
By Tuesday afternoon, there could be enough moisture moving into
coastal GA to squeeze out a few showers.

An approaching upper trough mid week will push the surface high
off the Mid-Atlantic coast, allowing moisture to increase over
the area. The cold advection will wane, with temps rising a
couple degrees. Scattered showers and thunderstorms will be
possible, especially in the afternoon.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
A weak cold front will move through Thursday night or Friday,
then a potentially stronger cold front will move through late in
the weekend. Relatively quiet weather is anticipated with temps
getting back close to normal.

&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
VFR conditions should prevail at CHS/JZI/SAV terminals through 00Z
Monday. However, low clouds could drift back onshore between 06Z-12Z
Sunday, leading to TEMPO MVFR cigs at any terminal. The greatest
potential for this to occur should be at SAV, where a TEMPO group
for MVFR cigs between 08Z-12Z has been included in the most recent
TAF issuance. The bulk of guidance suggests high pressure to build
across the area while low pressure pulls further away from the coast
Sunday afternoon. A few showers could develop near the coast prior
to this occurring, so VCSH remains in the forecast at CHS/SAV late
morning, but showers could linger a bit longer at JZI given its
closer proximity to the coast.

Extended Aviation Forecast: Mainly VFR. Afternoon showers/tstms
will return Wed and Thu, possibly resulting in brief flight
restrictions.

&&

.MARINE...
Today and Tonight: The pressure gradient will strengthen across
local waters as high pressure builds inland and low pressure exits
further offshore. This will favor northeasterly winds gusting
upwards to 25-30 kt by late morning and conditions persisting
through the remainder of the day and the night. Seas will also
respond by building across local waters, generally to 5-7 ft,
largest across nearshore waters off the Charleston County Coast and
across outer Georgia waters. Small Craft Advisories remain in place
today and tonight, starting across coastal waters at 6 AM this
morning, with the exception being across the Charleston Harbor,
which starts at 10 AM this morning.

Seas of 6 ft or greater as well as occasional 25 kt gusts will
continue through Monday evening for the nearshore waters and
through Monday night for the offshore waters. Small Craft
Advisories are in effect. Conditions improve thereafter as the
surface high to the north begins to weaken, relaxing the
gradient.

Rip Currents: Increasing swell height/period and enhanced
onshore flow will result in a Moderate risk today and High risk
Monday.

&&

.TIDES/COASTAL FLOODING...
The persistent NE flow will result in steadily building tidal
departures through early in the week, with anomalies potentially
getting above 1 ft. At the moment, tides in Charleston should
fall just short of minor flooding, but it could be close with
the Mon and Tue afternoon high tides.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...Small Craft Advisory from 10 AM this morning to 2 AM EDT
     Monday for AMZ330.
     Small Craft Advisory from 6 AM this morning to midnight EDT
     Monday night for AMZ350-352-354.
     Small Craft Advisory from 6 AM this morning to 6 AM EDT
     Tuesday for AMZ374.

&&

$$

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