-- Discussion containing changed information from previous version are highlighted. --
352
FXUS62 KCHS 231033
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
633 AM EDT Thu May 23 2024

.SYNOPSIS...
High pressure will persist through tonight. Diurnal convection
and hot temperatures are expected during the holiday weekend. A
cold front might bring impacts to our area on Tuesday.

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
Satellite imagery and surface obs show an area of stratocu that
has developed in the last few hours over inland southeast
Georgia and some minor visibility restrictions up across the
rest of the forecast area. Appears fog will not be an issue this
morning. Just cosmetic tweaks made to the forecast for the early
morning update.

Previous discussion...
Overnight composite analysis reveals a upper level high pressure
across Mexico into the Gulf with ridging extending up along the
southeast Atlantic coast. Surface high pressure stretches along the
coastal waters. Complex of shower and thunderstorms is pushing
slowly through Mississippi and appears to be weakening. But a fair
amount of debris cloud cover is expanding into the southeast region.
Otherwise, quiet conditions prevail across our region. Temperatures
are milder than last night. Along with some semblance of a weak
southeast wind, fog potential through the morning is looking much
lower compared to Wed morning.

Today: Upper level ridge axis and surface high pressure will slowly
slip off the coast today leading to a bit more S/SW flow developing
across the region. Upstream higher level cloud cover will be
traversing the region through the course of the day, and there again
be some sct to bkn Cumulus development late morning and through the
afternoon. High resolution guidance is again generating some very
isolated showers this afternoon/early evening over parts of eastern
Georgia into South Carolina, although forecast soundings remain
capped. Keeping the forecast dry at this juncture.

Temperatures: Warming aloft - 850 MB temps warming to around 17C, a
few degrees C warmer than Wednesday - suggest daytime highs in
the upper 80s to around 90F inland. Cooler temperatures along
the coast as per usual.

Tonight: Upper ridge axis will flatten out across the Deep South and
southeast CONUS courtesy of a couple of convectively induced waves
rippling out of the central and lower Mississippi River Valley and
through the southeast and mid Atlantic region. There may be a
surviving cluster of showers/thunderstorms working across the
Carolinas during the course of the night, although all recent
guidance runs and blended guidance probabilities suggest convection
remains just north of the forecast area...from the SC Pee Dee region
into North Carolina and Mid Atlantic. Our inclination is to have a
dry forecast through the overnight period into early Friday
morning. Temperatures will continue to run mild, in the upper
60s to lower 70s for lows and a touch warmer along the coast.
-- End Changed Discussion --

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY/...
Friday: The mid-levels will consist of zonal flow over our region,
with a weak disturbance just passing to our north during the evening
and overnight. At the surface, High pressure will be centered in the
western Atlantic, with it`s periphery trying to reach into the
Southeast. A front will stay well to our north and northwest.
Meanwhile, weak surface troughing should develop near our area
during the day and persist into the overnight. Flow around the
western Atlantic High will usher moisture into our area, with PWATs
rising to almost 1.85" during the afternoon. Temperatures peaking in
the lower 90s will cause instability to increase. Models remain in
good agreement indicating isolated to scattered thunderstorms
forming along the sea breeze in the afternoon, especially across our
SC counties. Locally heavy rainfall is possible along with gusty
winds, especially in the stronger storms. Convection should
gradually decrease into the evening and overnight. Lows will be
mild, ranging from the upper 60s far inland to the lower 70s just
about everywhere else.

Saturday: Weak troughing will form off the Southeast coast in
response to weak ridging forming over the Southeast U.S. Surface
High pressure will remain in the western Atlantic while troughing
persist over a portion of the Southeast. Low level winds will
continue to usher a decent amount of moisture into our area. Though,
it`s still uncertain how high PWATs will get. High temperatures
peaking in the lower to middle 90s away from the beaches will
generate a decent amount of instability. Therefore, scattered to
maybe numerous convection is expected to form along the sea breeze
in the afternoon. Rising DCAPEs point to some marginally severe
storms with damaging wind gusts being the main concern. But there
will also be locally heavy rainfall. Convection will gradually
decrease into the evening and overnight. Lows will remain mild,
ranging from the upper 60s far inland to the lower 70s just about
everywhere else.

Sunday: The mid-levels will consist of a weak ridge over the
Southeast. It should shift offshore as time progresses. The surface
pattern will be similar to previous days with High pressure in
the western Atlantic while troughing persist over a portion of
the Southeast. Low level winds will continue to usher a decent
amount of moisture into our area. High temperatures are expected
to reach the lower to middle 90s away from the beaches, which
will generate a decent amount of instability. Another round of
pulse convection is expected to form along the sea breeze in the
afternoon. Some storms could be marginally severe with damaging
winds being the main concern, followed by locally heavy
rainfall.

&&

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
West southwest mid-level flow will be over our region Sunday night.
A longwave trough will gradually develop over the eastern half of
the U.S. Monday into Tuesday, then prevail into Wednesday. Surface
High pressure will remain in the western Atlantic through Monday,
with surface troughing over portions of the Southeast. Expect
convection along/near the sea breeze each afternoon/evening,
decreasing during the overnight hours. A cold front should move
through our area on Tuesday, bringing more numerous convection. High
pressure is expected to bring drier conditions on Wednesday.
Temperatures will remain above normal through Tuesday, then drop to
near normal on Wednesday.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --
VFR conditions are expected at the CHS/JZI/SAV terminals
through 12Z Friday, although some shallow ground fog could
briefly impact the terminals through 13Z.

Otherwise, another round of "heating of the day" VFR Cumulus
will develop late morning and persist through the afternoon and
cloud cover may become BKN at times. Cloud cover fades heading
into the evening with VFR conditions prevailing through early
Friday morning.

Light southerly to westerly surface winds overnight. Sea breeze
development is anticipated during the afternoon with winds
becoming southerly around 10 knots with the sea breeze push.

Extended Aviation Outlook: Brief flight restrictions are possible
due to showers/thunderstorms each afternoon/evening.
-- End Changed Discussion --

&&

.MARINE...
Surface high pressure along and off the southeast coast will yield
southerly winds across the coastal waters through tonight with
a sea breeze push anticipated along the coast during the
afternoon hours. Speeds will run 5 to 10 knots overall with
some increase during the afternoon (10 to 15 knots) with the sea
breeze. Seas of 2 feet or less anticipated through tonight.

Extended Marine: High pressure will persist in the western Atlantic
while surface troughing prevails over the Southeast U.S. This will
lead to a typical summer wind pattern. Each day, winds will back and
be stronger along the land/sea interface with the formation of the
afternoon sea breeze. Gusts could approach 20 kt across the
Charleston Harbor with the passage of the sea breeze. Each night,
winds should veer as the low level jet sets up along the coast.
Additionally, convection is expected to return this weekend and
persist into next week.

Rip Currents: The combination of astronomical influences from
the Full Moon and a small swell will lead to an enhanced risk of
rip currents today at all of our beaches. The in-house Rip
Current Calculator continues to indicate a Moderate Risk, while
the Rip Current MOS points to a Low Risk. For consistency, we
have maintained the Moderate Risk. Rip currents are most likely
at Tybee Island.

&&

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

&&

$$

NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...