047
FXUS62 KCHS 261925
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
325 PM EDT Sat Apr 26 2025

.SYNOPSIS...
A cold front will move through tonight, followed by high
pressure through much of next week. Another cold front could
approach the region late in the week.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
This afternoon, GOES Day Cloud Type RGB has nicely identified a
corridor of developing cumulus clouds and isolated showers between a
passing mid-level disturbance and the sea breeze. SPC mesoscale
analysis indicated the MLCAPE around 1500 J/kg with little to no
CIN. Given normalized CAPE between .1 to .15 units, instability
should support a cluster of thunderstorms along the sea breeze late
this afternoon and evening. Once these storms cross the sea breeze
they should steadily dissipate, especially after sunset.

The sea breeze should drift inland through this evening,
occasionally initiating an isolated cell. Recent runs of the HRRR
indicates at a cold front will generally backdoor across the
forecast area late tonight. The front is timed to reach Berkeley and
Charleston Counties between 8-9Z, advancing south across the
Savannah River Valley by daybreak Sunday. Northeast winds will
develop in the wake of the front, increasing to around 10 mph. Using
a blend of MOS, low temperature are forecast to range in the low 60s
inland to the mid 60s along the coast.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
A cold front will push to the south Sunday into Monday while high
pressure builds from the north. Isolated to scattered showers and
thunderstorms will be possible over southeast Georgia where better
moisture and instability resides, perhaps aided by weak shortwave
energy passing through Sunday night into Monday. Across southeast
South Carolina, dry conditions should prevail. High temperatures on
Sunday will range from the upper 70s near the northern zones to
upper 80s near the Altamaha River in Georgia. Upper 70s to lower 80s
will be the rule for Monday. Lows will be within a few degrees of
normal.

High pressure will shift offshore on Tuesday. Large scale subsidence
under a mid level ridge building overhead will maintain a rain-free
forecast. Highs will largely be in the low to mid 80s, except a
touch cooler near the immediate coast and at the beaches.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
Mid level ridge will remain over the Southeast through midweek,
before exiting offshore in advance of a larger scale trough moving
towards the East Coast. At the surface, Atlantic high pressure will
extend across the area through at least Thursday. A cold front will
then approach late week. Isolated diurnal showers/thunderstorms will
be possible on Thursday, then higher rain chances are expected
Friday with the front.

&&

.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
Prior to the 18Z TAFs, GOES water vapor indicated a mid-level
shortwave drifting east across the Lowcountry of SC. Between
20-21Z, isolated to scattered showers and thunderstorms should
develop between the disturbance and a developing sea breeze. The
convection potential will be highlighted in the KCHS and KJZI
TAFs with a TEMPO from 20-23Z. Any convection should dissipate
an hour or two following sunset this evening. A cold front is
timed to pass over KCHS/KJZI by 10Z and KSAV by 13Z. It is
possible that periods of MVFR ceilings may develop along and
ahead of the front, TAFs will indicate SCT025 at this time.
Following the front, winds will turn from the northeast and
cloud cover should decrease.

Extended Aviation Outlook: Prevailing VFR.

&&

.MARINE...
A cluster of thunderstorms is forecast to develop along the sea
breeze near SC Lowcountry coast late this afternoon and evening.
Once the storms cross the sea breeze, the storms should dissipate
over the adjacent Atlantic waters. This evening, the pattern should
support southwest winds between 10 to 15 kts, with gusts around 20
kts near the coast. A back door cold front is timed to reach the SC
nearshore waters late tonight, reaching the GA waters around
daybreak Sunday. As the front passes, winds should shift from the
northeast, remaining between 10 to 15 kts. Seas will generally range
between 2 to 4 ft.

Sunday through Thursday: Gusty east-northeast winds are expected to
develop on Sunday as high pressure builds from the north behind a
cold front. Some low 20 kt gusts will be possible, but conditions
will stay below Small Craft Advisory criteria. The pressure gradient
will ease Sunday night into Monday. No additional marine concerns
through midweek with winds turning southerly as high pressure shifts
offshore. Speeds will average around 10 kt or less, with some
enhancements possible near the coast with the sea breeze. Seas will
settle into the 2-3 foot range.

Rip Currents: A 2 ft, 9 sec swell will persist today. Breezy
conditions along the sea breeze coupled with peaking
astronomical influences will support a high risk for all beaches
until 8 PM this evening.

The combination of gusty onshore winds, lingering 2 ft, 9
second swell and astronomical influences will lead to a High
Risk of rip currents at Georgia beaches on Sunday and a Moderate
Risk at South Carolina beaches. An elevated risk of rip
currents is expected to persist into Monday.

&&

.TIDES/COASTAL FLOODING...
Elevated tide cycles are expected Sunday into the middle of next
week due to the upcoming new moon and perigee. Favorable northeast
to east winds will drive tidal departures up, and Coastal Flood
Advisories will be possible. For the Charleston Harbor tide gage,
minor coastal flooding is currently forecast with the evening high
tides Sunday through Tuesday, with a possibility for moderate
flooding (7.5 ft MLLW) mainly on Sunday. For the Fort Pulaski gage,
minor flooding (9.5 ft MLLW) is possible with the Sunday and Monday
evening high tides.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...High Risk for Rip Currents through Sunday evening for GAZ117-119-
     139-141.
SC...High Risk for Rip Currents until 8 PM EDT this evening for
     SCZ048>051.
MARINE...None.

&&

$$

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