978
FXUS62 KCHS 210812
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
412 AM EDT Sat Sep 21 2024

.SYNOPSIS...
High pressure across the region will prevail through early next
week. A weak cold front may approach from the west around the
middle of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Today: Aloft, a trough will continue to nudge east across the
western Atlantic while a ridge centered across Texas extends further
east across the Deep South and into the Southeast United States by
late day. At the sfc, high pressure will remain across the Southeast
United States, but will show signs of drifting off the Mid-Atlantic
coast with the approach of additional mid-lvl vort energy traversing
the Northeast. The pattern will result in notable subsidence across
the region, bringing mostly dry weather locally under few clouds.
Given mid-lvl ridging expanding across far inland areas, sfc temps
could warm a degree or two higher than the previous day. Afternoon
highs should range in the low-mid 80s closer to the coast to upper
80s inland. A few areas could top out near 90 degrees across far
inland zones of Southeast Georgia.

Tonight: Dry conditions will prevail with sfc high pressure settled
across the local area and mid-lvl ridging extending from the west
aloft. Although a bit of cirrus could move across the region,
conditions should favor another decent radiational cooling night
with light/calm winds for much of the night for areas away from the
coast. Low-lvl moisture is a bit lacking, so fog is generally not
anticipated. Overnight lows should range in the mid 60s inland to
upper 60s/lower 70s near the beaches.

&&

.SHORT TERM /SUNDAY THROUGH TUESDAY/...
The synoptic pattern will remain largely unchanged through the
period with a large upper ridge across the Deep South, slowly
progressing eastward with time. Broad surface high pressure will
remain over the eastern CONUS and extreme western Atlantic providing
subsidence and generally quiet weather conditions through the
period. Mostly sunny skies are expected each day through Tuesday.
Any potential for convection will be largely suppressed due to
relatively dry air aloft and the lack of significant forcing
mechanisms. No mentionable rainfall chances have been included
during this period.

Temperatures will be mild/slightly above normal through the period
due to the ridge aloft with highs in the upper 80s/low 90s each day.
Sunday and Monday night will feature lows in the upper 60s inland
and lower 70s near the coast.

&&

.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
The long-term forecast features increasing chances for showers and
perhaps a few thunderstorms. The region will see a slight uptick in
moisture as the upper ridge axis shifts offshore Wednesday. Slight
chance POPs return Wednesday evening with peak rain chances
anticipated to occur later in the week as an upper trough and cold
front approach. Temperatures will start mild with highs in the upper
80s initially and trending cooler into the lower 80s by next weekend.

&&

.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
VFR conditions are expected at CHS/JZI/SAV terminals through 06Z
Sunday.

Extended Aviation Outlook: VFR conditions expected to prevail.

&&

.MARINE...
Today and Tonight: A modest pressure gradient will prevail between
high pressure inland and a weak trough well south of the local area.
The setup will yield 10-15 kt northeast winds for much of the day
with a few gusts up to 20 kt across offshore Georgia waters as well.
Expect winds to gradually veer and weaken overnight as the pressure
gradient relaxes. Seas will generally range between 2-4 ft across
nearshore waters and 4-5 ft across offshore Georgia waters during
the day, but should gradually subside a foot during the night.

Sunday through Wednesday: As high pressure begins to migrate
offshore, winds will shift out of the east/southeast around 10 kt or
less. Seas will average 2-3 ft within 20 nm and 3-4 ft for the GA
waters from 20-60 nm.

Rip Currents: Onshore winds approaching 10-15 kt, 2 ft swell near 10
seconds along with local RCMOS model data favor a Moderate Risk for
rip currents along Georgia beaches today.

&&

.TIDES/COASTAL FLOODING...
Coastal flooding is likely again up and down the entire coast
with high tide late Saturday morning. For Charleston Harbor, the
current 7.9 ft MLLW forecast look solid. There is some concern
that levels could reach major flood levels (8.0 ft MLLW), but
this scenario only has about 10% probability of occurrence. A
Coastal Flood Watch for Charleston and Colleton Counties will
not be issued with this forecast update for this reason. Fort
Pulaski looks to say solidly in the minor flood category.
Coastal Flood Advisories will be needed for all coastal zones
from late morning into the early afternoon hours.

Positive tidal anomalies and high astronomical tides from the recent
full moon will lead to elevated tides through the weekend. Although
the astronomical high tides are lowering, coastal flooding is
expected with each daytime high tide cycle along the Charleston and
Colleton County coasts.

&&

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

&&

$$

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