268
FXUS62 KCHS 301205
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
805 AM EDT Sat Aug 30 2025

.SYNOPSIS...
High pressure will extend across the area through early next
week while a stationary front lingers just off the coast. A
cold front will move through on Thursday.

&&

.NEAR TERM /THROUGH TONIGHT/...
Today: Aloft, mid-lvl shortwave energy will ripple across the
Southeast United States along the southern base of a large trough
centered across the Northeast. At the sfc, a stationary front
remains positioned south of the local area near the Florida/Georgia
state line, but mid-upper lvl divergence along/near this feature and
to the north should help spawn low pressure over northern Florida,
which then tracks east-northeast to the nearby Atlantic late morning
and afternoon. Although some uncertainty remains in the eventual
path of low pressure, a bulk of guidance indicates ample moisture
(PWATs around 2.0 inches), isentropic lift north of the front/low,
and mid-upper lvl support for scattered to widespread
showers/thunderstorms mid morning into late afternoon locally.
Greatest precip coverage is anticipated along and south of I-16
across Southeast Georgia, but could potentially extend north
across coastal areas into Southeast South Carolina, where low-
lvl convergence occurs along the land/ocean interface. SBCAPE is
rather unimpressive and mid-lvl lapse rates poor, suggesting
the threat for severe weather to remain low for the local area,
but there remains a chance for a stronger thunderstorm to occur
across coastal Southeast Georgia, mainly near the Altamaha
River. The greater concern will be brief heavy rainfall and the
potential for minor flooding issues across Southeast Georgia
(mainly near the coast) and perhaps into far southern Southeast
South Carolina (near the coast), where the latest forecast
calls for 1 to 2.5 inches of rainfall by the end of the day.
These totals are highly dependent on the eventually path of low
pressure across the Atlantic this afternoon, which could reduce
these numbers quite a bit. However, should trends indicate
rainfall to occur over a shorter window of time across land,
Flood Advisories and/or perhaps a Flash Flood Warning could
become necessary. WPC continues to highlight much of the local
area in a Marginal Risk for excessive rainfall.

Given precip coverage, cloudiness, and light northeasterly winds
associated with high pressure attempting to spill into the area from
the north, high temps will remain well below normal for this time of
year. In general, temps should peak in the upper 70s inland to lower
80s near the coast and far southern areas of Southeast Georgia near
the Altamaha River.

Tonight: Guidance suggests the bulk of shower and/or thunderstorm
activity to wane and/or shift offshore by early evening while high
pressure attempts to strengthen inland. Much of the area is expected
to be dry by mid-evening with the exception of a few lingering
showers along the coastal corridor overnight. Light north/northeast
winds associated the high pressure should result in low temps in the
mid-upper 60s inland to lower 70s near the beaches.

&&

.SHORT TERM /SUNDAY THROUGH TUESDAY/...
Cooler and drier high pressure will continue to build from the
north Sunday through Tuesday. Meanwhile a weak front will remain
stalled just off the coast. Quite a bit of moisture will remain
in place across the area Sunday though somewhat higher PWs will
exist across coastal southeast GA. The coastal front could
provide a focus for convection as well as a late afternoon
shortwave swinging through from the northwest. The greatest
coverage should be across southeast GA.

A surge of drier air will move in from the north Monday into
Tuesday with PWs below 1" in most areas. The weak coastal front
will persist through this period and we could still see a few
showers or tstms affecting immediate coastal areas. Locally
heavy rainfall will be possible.

&&

.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
The surface high to the north will shift northeast away from the
area midweek. A large closed upper low will then move into the
central United States. Low pressure could develop off the
Southeast coast Wednesday or Thursday, then lift northeast. The
local impacts of this will depend heavily on exactly where the
low develops, as it may be far enough offshore to limit the
local effects.

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
Periods of MVFR conditions are likely at CHS/JZI/SAV terminals
this morning into the afternoon, mainly due to showers across
the area. There is a possibility of IFR conditions at JZI and
SAV terminals as well during heaviest showers this morning where
TEMPO groups have been included for reduced vsbys during
showers. Thunderstorms could also develop at the SAV terminal by
early afternoon, where VCTS has been included until early
evening. Showers are then expected to shift offshore by around
00Z Sunday, but MVFR cigs could hold on at all terminals through
the night as high pressure builds across the area from the
north.

Extended Aviation Forecast: Occasional MVFR ceilings possible
through Monday as a weak front remains stalled along the coast.

&&

.MARINE...
Today and Tonight: Low pressure will attempt to develop/track
across Florida and track across the nearby Atlantic while sfc
high pressure holds across the Carolinas into Central Georgia. A
few stronger thunderstorms are possible as this process unfolds,
mainly across Georgia coastal waters. Although conditions are
expected to remain below Small Craft Advisory levels outside
convection, the pressure gradient will show signs of tightening
as low pressure shifts offshore, favoring winds to back from
southeast to northeast and increase to 15-20 kt across a bulk of
local waters this afternoon through the night (highest outside
the Charleston Harbor). Seas will also slowly build in response
to a more favorable wind direction, building from 1-3 ft today
to 2-4 ft during the night.

Sunday through Tuesday: A moderate NE gradient will persist as
high pressure continues to build from the northwest while a
coastal trough sits offshore. We`ll likely need Small Craft
Advisories for most if not all zones during much of this time
due to a combination of 25 kt gusts and 6+ ft seas.

Wednesday through Thursday: Quieter conditions expected.

Rip Currents: A moderate risk for rip currents is in place for
all beaches on Sunday due to the increasing strength of the
pressure gradient.

&&

.TIDES/COASTAL FLOODING...
Tidal departures could begin to build over the weekend into
early next week as low pressure develops offshore and a wedge of
high pressure lingers inland. Tides could get close to minor
flood thresholds in the Charleston Harbor by Monday yielding a
risk for coastal flooding across coastal areas of Charleston and
Colleton Counties during mainly the afternoon high tide cycle.
This risk may extend into the middle of next week depending on
how strong the pinched gradient gets.

&&

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

&&

$$

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