338
FXUS62 KCHS 241920
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
320 PM EDT Sat May 24 2025

.SYNOPSIS...
Expect an active weather pattern to begin tomorrow through the
upcoming week as a frontal boundary lingers in the vicinity and
a series of upper disturbances move through the region.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
Quiet conditions continue to prevail across the region under sfc
high pressure, with latest observations showing sunny skies and
highs in the upper 70s to 80s. Much like yesterday, will see the sea
breeze develop and progress inland from the beach during the mid to
late afternoon, with gusts approaching 15 to 20 MPH at times.

Tonight:

Mid-level shortwave lifts across South Carolina throughout the
overnight period, bringing with it chances for showers and perhaps a
few thunderstorms. Moisture will be hard to come by initially
though, and with dry air still in the lower levels, may see more in
the way of virga than showers until closer to daybreak. Moisture and
coverage then increase, especially across the Tri-County/Pee
Dee/Grand Strand area, with those along and south of a line from
Beaufort to Statesboro still remaining largely dry. Thus, in terms
of rainfall, expect accumulations to remain near to less than a
tenth of an inch. Lows during this time will also be somewhat mild
under increasing cloud cover, as temperatures only fall into the
upper 60s to lower 70s.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
As a large cut-off low shifts off the New England coastline, a wavy
west-east oriented frontal boundary will linger nearby and cause for
a unsettled period of showers and thunderstorms to last through the
upcoming week. At the surface, west-southwesterly mid-lvl flow will
persist over the Southeast as a moist airmass spreads across the
Atlantic seaboard. This weak frontal boundary will lift north on
Sunday afternoon as a potent shortwave passes through the southern
half of South Carolina. Due to warm surface temperatures across
this airmass, moderate instability will develop in the early
afternoon and thunderstorms are likely to form along the stalled
frontal boundary nearby. CAMs have been indicating the
potential for a loosely convective cluster to move through the
Charleston metro area in the afternoon. Additionally, HRRR/NAM
forecast soundings have been hinting at SBCAPE values ~1000-1500
J/kg .. this is an increase from the previous 24 hrs. Although,
deep-layer shear remains weak, lapse rates could become quite
steep in some spots where daytime heating occurs and there is
potential for some of these storms to become severe. Thus,
isolated damaging winds and the possible hail formation cannot
be ruled out tomorrow.

Another shortwave will approach the region on Monday, as an
associated cold front approaches from the west. More locally .. this
aforementioned frontal boundary will drop to the south into the
region and stall. With instability and moisture sticking around,
expect showers and thunderstorms to continue on Monday and Tuesday.
However, given the continued lack of shear, the severe threat looks
to remain low .. but will continue to monitor this.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
A seasonable convective pattern looks to make a return on Wednesday
through the rest of the week as the frontal boundary continues to
linger nearby and a series of upper-lvl shortwaves continue to make
a pass through the region. Expect scattered showers and
thunderstorms to develop each afternoon along and/or out ahead of
the seabreeze. Weak troughing will remain over the Southeast and
seasonable temperatures can be expected through the end of the week.

&&

.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
VFR conditions conditions are expected to continue through the
evening. Primary feature of note today is the sea breeze which
progresses through the terminals early to mid afternoon, with
scattered cu along and ahead of the sea breeze, and moderate onshore
winds with gusts to around 15 kt behind the sea breeze. A few
showers could begin to work into the Lowcountry very early Sunday
morning, with moisture and coverage then expected to increase during
the remainder of the period.

Extended Aviation: Some brief flight restrictions could be
possible Monday through Wednesday as showers and thunderstorms are
expected with the lingering frontal boundary nearby.

&&

.MARINE...
This afternoon and tonight: Sea breeze brings gusty winds near the
coast by mid-afternoon with increasingly onshore wind direction
across the waters this evening. Light to moderate winds prevail
overnight as the surface boundary lifts back across the GA waters.
Limited incoming swell keeps seas around 2 to 3 ft the remainder of
this afternoon and evening.

Sunday through Wednesday: With the frontal boundary nearby and
series of shortwaves passing through, expect showers and
thunderstorms through the period. No significant marine concerns
into next week. Expect winds to be generally 10 to 15 kt with an
increase in winds each afternoon associated with the seabreeze.
Generally seas will be 2 to 3 ft, with some mix of 4 footers in the
outer most waters. With a somewhat modest swell and higher than
normal tidal range, a Moderate risk for rip currents is expected
on Sunday at all beaches.

One note to boaters: Stronger than normal currents can be expected
on tidal waterways through the holiday weekend given large tidal
ranges as we approach the Perigee on Monday. Early afternoon low
tides will be followed by quickly rising water, which has, in the
past, resulted in dangerous conditions as area sandbars quickly
become submerged.

&&

.TIDES/COASTAL FLOODING...
A surge of northeast winds earlier today has result in tidal
departures in excess of 1 ft at both the Charleston Harbor and Fort
Pulaski. This afternoon, a sea breeze will maintain onshore flow
through high tide this evening, around 6:27 PM. Departures are
expected to gradually subside during the second half of the tide
cycle late this afternoon into early this evening. The total water
forecast will be updated to increase tide levels at Charleston
Harbor to 7.3 ft MLLW, peaking within minor flood stage. A Coastal
Flood Advisory will be in effect for Charleston and coastal Colleton
Counties until 8 PM this evening.

Next week, a lunar perigee will occur on Monday with a New Moon on
Tuesday. The evening high tides at Charleston should produce coastal
flooding, especially on Monday and Tuesday. Fort Pulaski could peak
within minor flood stage on Tuesday.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...Coastal Flood Advisory until 8 PM EDT this evening for SCZ049-
     050.
MARINE...None.

&&

$$

NEAR TERM...SST
SHORT TERM...Dennis
LONG TERM...Dennis
AVIATION...Dennis/SST
MARINE...Dennis/SST