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214
FXUS62 KCHS 201747
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
147 PM EDT Mon May 20 2024

.SYNOPSIS...
High pressure will persist for most of this week. A series of
upper level disturbances should impact our area next weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
Cool air advection (between building ridging inland and
troughing well offshore) is the name of the game across the
area as we move toward midday, with widespread strato-cu
developing at the top of BL in the modified-maritime airmass.
Strengthening upper subsidence will keep a dry forecast in
place. Highs in the upper 70s to lower 80s anticipated...coolest
along the coast and around Lake Moultrie.

Tonight: Any diurnal cloud cover will fade quickly this evening
with mainly clear skies anticipated thereafter. Along with
diminishing winds and lower dewpoints, lows will dip into the
upper 50s inland to the middle 60s along the coast.

&&

.SHORT TERM /TUESDAY THROUGH THURSDAY/...
Tuesday: A positively tilted mid-level trough will be just off the
Southeast U.S. coast in the morning. It will transition into a cut-
off Low in the evening and overnight. Meanwhile, a ridge will
strengthen over the Southeast U.S. during the day and at night.
Broad High pressure centered to our north in the morning will shift
off the Mid-Atlantic Coast as the day progresses. Though, it`s
southern periphery will continue to be the dominant synoptic feature
for our weather during the day and into the night. Subsidence will
yield dry conditions with mostly sunny/clear skies. High
temperatures should be in the mid 80s, except cooler at the beaches.
Lows should range from the upper 50s far inland to the mid 60s
closer to the coast.

Wednesday: The mid-levels will consist of a cut-off Low meandering
off the Southeast coast, while a ridge prevails over the Southeast
U.S. At the surface, High pressure along the Southeast coast in the
morning will shift offshore into the afternoon. A front will slowly
approach from the north and northwest during the evening and
overnight. Though, it won`t make it near our area as the periphery
of the High remains the dominant synoptic feature. Ongoing low and
mid-level subsidence will continue to bring our area dry conditions
with mostly sunny/clear skies. Expect an inland moving sea breeze
during the afternoon. Highs will peak in the upper 80s, except
cooler at the beaches. Lows should range from the lower 60s far
inland to the lower 70s along the immediate coast.

Thursday: A mid-level ridge over the Southeast U.S. in the morning
will weaken as the day progresses. Surface High pressure just off
the Southeast coast in the morning will move further offshore as the
day progresses. The front to our north and northwest will continue
to approach. However, it won`t make it to our area. This periphery
of the High will bring yet another day with dry conditions. Expect
fair weather cumulus in the afternoon along with a sea breeze. High
temperatures should be in the upper 80s to lower 90s, except cooler
at the beaches.

&&

.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
Expect west southwest mid-level flow over our region Thursday night.
A weak trough may pass to our north Friday night into Saturday,
possibly followed by weak ridging on Sunday. Surface High pressure
in the western Atlantic Thursday night will shift further offshore
into the weekend. A cold front could approach from the north and
northwest later Friday, then lift north on Saturday. Expect some
diurnal convection on Friday, with convection more likely during the
weekend. High temperatures will be a few degrees above normal each
day.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
-- Changed Discussion --
KCHS/KJZI/KSAV: Mainly VFR prevails this afternoon, though some
locations, like KCHS, continue to experience some MVFR cigs at
least occasionally. Increased mixing mid afternoon will continue
to scatter/raise ceilings, with VFR prevailing late afternoon
through the evening. Late tonight, clear skies and light to calm
winds will allow for efficient radiational cooling, and
shallow/light fog could develop, with greatest chances for
inland southeast South Carolina through the pre-dawn hours. Have
included a few hours of MVFR fog at KCHS. Meanwhile, KJZI is
less likely to fully decouple and KSAV is further removed from
the better moisture pooling, with VFR prevailing at both of
these sites. Mixing returns widespread VFR shortly after sunrise
Tuesday with mainly light northeast winds persisting.

Extended Aviation Outlook: VFR.
-- End Changed Discussion --

&&

.MARINE...
Surface high pressure will be building along the Atlantic coast
through today. The resulting tighter pressure gradient across
the coastal waters will continue to produce gustier northeasterly
winds today and tonight. Gusts of 20 to 25 knots will be common
today with seas building to 3 to 5 feet in the nearshore waters
and 4 to 6 feet in the outer Georgia waters. We have hoisted a
Small Craft Advisory for the outer Georgia waters for today
through early evening. It`s a bit more marginal across the
nearshore waters with no headline planned at this time. But we
will continue to monitor conditions for possible expansion of
the SCA as we go through the day.

Extended Marine: NE winds on Tuesday will shift around to the SE by
later Wednesday as High pressure gradually shifts off our coast.
This will lead to a more typical summer wind pattern beginning on
Thursday. That`s when mariners should expect backing winds during
the day, along with stronger wind gusts along the land/sea interface
with the formation of the afternoon breeze. At night, winds should
veer as low level jetting sets up along the coast.

&&

.TIDES/COASTAL FLOODING...
A Coastal Flood Advisory has been issued for the Charleston and
Colleton County coastlines around this time of this evening`s
high tide (7 PM).

The combination of rising astronomical tides with the upcoming Full
Moon and moderate NE winds will cause tides to be elevated through
the middle of this week. Minor flooding is possible with the evening
high tides again Tuesday and Wednesday along the South Carolina
coast.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...Coastal Flood Advisory from 6 PM to 8 PM EDT this evening for
     SCZ049-050.
MARINE...Small Craft Advisory until 6 PM EDT this evening for AMZ350.
     Small Craft Advisory until 9 PM EDT this evening for AMZ374.

&&

$$

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