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000
FXUS62 KCHS 192240
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
640 PM EDT Fri Apr 19 2024

.SYNOPSIS...
A slow moving front will bring unsettled weather to the region
Saturday through early next week. High pressure will then
return and prevail into the middle of next week.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Radar early this evening clearly indicates the sea breeze
aligned somewhat north to south, and roughly splitting the
forecast counties in half. There can be a couple of stray
showers early on near and actually east of the sea breeze.
Otherwise, rainfree.

For the late evening and overnight, upstream convection will
slide east-southeast and interact with whatever is left of the
sea breeze. That activity looks to be associated with a cold
front that will approach the northwest tier late. These
conditions will result in at least a slight chance of showers
and t-storms over the Charleston quad-county region between
about 10 pm and 5 am. The rest of the region currently has no
mention of convection in the forecast.

It`ll be a warm night for this time of year, and mainly in the
mid and upper 60s.


&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
Mid-level ridging will be centered across the southern Gulf of
Mexico Saturday with a shortwave over southeast Texas slowly heading
east. Across eastern Canada, a longwave trough will slowly
translate off the coast with a weak cold front oozing to the
south. The first batch of precipitation is forecast to arrive
with the shearing out wave (originating from Texas) Saturday
afternoon into evening. PWATs ahead of the wave Saturday are
forecast to be around 1.4" along with warm cloud depths around
7kft. Initially, precipitation will likely struggle to hold
together across the Low Country due to the dry air. Expect high
temperatures in the upper 80s.

By 5 PM and 8 PM showers and thunderstorms will fill in towards
the coast Saturday. MLCAPE values are forecast to be around 1000
J/kg which will support thunder across all zones. The wave will
then start to exit the coast Sunday morning with precipitation
temporarily coming to an end and a weak cold front oozing to the
SC coastline.

Another wave will then approach the area Sunday afternoon and is
slightly more amplified that in previous runs. As this occurs,
surface cyclogenesis will occur off the coast of South Carolina
in association with the stalled frontal zone. Some global
guidance is indicating weak FGEN forcing occurring around 875
MB with the QPF field responding by arching back into a slight
banded feature. Given that the forcing is weak, most of the area
will likely see precipitation Sunday afternoon, but the focus
of the QPF being towards the Midlands of SC. Expect high
temperatures in the 60s interior SC Sunday, and upper 70s
forecast over GA (or south of the cold front).

Sunday night into Monday, temperatures will fall into the 50s
across the region. Latest global guidance continues to struggle
with Monday as another mid-level low, potentially rather
amplified, will cross the area. The latest run of the GEFS is by
far the most amplified, while the GEPS is the least amplified.
For now, have introduced PoPs into the forecast for Monday to
account for this.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Strong DAVA will set in across Georgia and South Carolina for
Tuesday as a mid-level low pressure exits the region. Temperatures
will fall below normal with no precipitation expected. Wednesday
into Thursday a strong closed low pressure is forecast to move
across the Great Lakes with the core of the DCVA remaining well
north of the area. Another cold front is then forecast to cross the
area Thursday into Friday. No precipitation is currently expected
with this frontal passage either.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
VFR conditions will prevail at CHS/JZI/SAV terminals through 00Z
Sunday. That said, there is a low end probability of an isolated
SHRA or TSRA at or near KCHS and KJZI after midnight, and a
slightly better chance for SHRA or TSRA at all terminals
Saturday afternoon/evening. Until trends can be better
determined, we opted no to include any mention in the TAFs at
this time.

Extended Aviation Outlook: A slow moving front will bring multiple
rounds of flight restrictions Saturday night through Sunday.
Further restrictions are possible Monday as low level moisture
remains trapped behind a frontal inversion. VFR conditions are
then forecast Tuesday and Wednesday as surface high pressure
approaches from the west.

&&

.MARINE...
A modest S to SW flow will continue through tonight as high
pressure remains offshore and a cold front drops into the
Southeast. Winds will be no higher than 10-15 kt, with 2 or 3
foot seas.

Saturday through Wednesday: South to southwest winds will persist
Saturday as a cold front slowly oozes towards the coast. Weak
surface cyclogenesis will then occur Sunday afternoon with winds
turning around from the northeast. Winds will then continue to
increase in speed and be sustained 20 to 25 kts with gusts 25 to to
30 kt. The highest probability for Small Craft Advisories appear to
be in the Atlantic waters adjacent to Charleston. Expect seas 4 to 6
ft. Winds will start to relax from the northeast Tuesday morning and
slowly veer around from the southwest Tuesday afternoon into
Wednesday.

&&

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

&&

$$

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