646
FXUS62 KCHS 242226
AFDCHS

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

.SYNOPSIS...
An active weather pattern will begin Sunday into the upcoming
week as a frontal boundary lingers in the vicinity and a series
of disturbances move through the region.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
A weak stationary front will remain to the south tonight.
Convection over the Deep South supported by a shortwave
propagating across the Tennessee Valley will slowly push east
through the night. Some weak convection, mainly isentropically
induced, could spread into far interior areas and into the
Charleston Tri-County prior to daybreak. This activity will be
fighting against some mid-level dry air, but there is still a
risk for some measurable rainfall. Slight chance pops around 20%
were highlighted to account for this. Lows will range from the
mid 60s well inland the lower-mid 70s at the beaches and
Downtown Charleston.

&&

.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 /22Z SATURDAY THROUGH THURSDAY/...
25/00z TAF Discussion:
KCHS/KJZI/KSAV: VFR through late morning Sunday with tstm
chances increasing at all terminals during the afternoon. There
remains some slight timing/coverage differences in the various
guidance, but TEMPO groups for MVFR conditions in TSRA were
introduced from roughly 19-23z to account for tstms at KCHS,
KJZI and KSAV. Refinements will be needed for future TAF
issuances, including possible inclusion of gusty winds and lower
vsbys/cigs.

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...
Tonight: East winds will veer to the southeast overnight with
speeds 10 kt or less. Seas will average 3 ft or less.

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.

Rip Currents: With a somewhat modest swell and higher than
normal tidal range, a Moderate risk for rip currents is expected
on Sunday at all beaches with a moderate risk along the Georgia
beaches for Memorial Day.

&&

.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.

&&

$$