Area Forecast Discussion
Issued by NWS Charleston, SC

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FXUS62 KCHS 290742
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
342 AM EDT Fri Mar 29 2024

.SYNOPSIS...
High pressure will extend into the area through Tuesday. A cold
front could affect the area around the middle of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Today: A broad trough aloft will continue to pull further away,
allowing for steady height rises as ridging starts to approach
from the west. High pressure at the surface that is initially
centered near the southern Appalachians will split into two
centers this afternoon. One will be near the southeast Georgia
coast, with the other near the Florida panhandle. Pwat down near
1/4 to 1/3 inch and strong March sunshine will allow for a fast
recovery of temperatures. We used a blend of the low level
thickness forecast with the MOS and NBM consensus, arriving at
the lower 70s just about everywhere. The barrier islands will be
in the mid and upper 60s due to an afternoon sea breeze. In
addition, a deep offshore flow this afternoon will allow for dew
points to drop to the upper 20s to mid 30s. This equates to
minimum RH values as low as near 20 or 25%.

Tonight: High pressure is found over south Georgia and north
Florida, as flat ridging moves in aloft. Winds will become light
or calm in most places, and that along with mostly clear or
clear skies (aside from some late night cirrus), will produce
good radiational cooling. This supports lower and middle 40s
inland, with upper 40s and lower 50s closer to the coast.

&&

.SHORT TERM /SATURDAY THROUGH MONDAY/...
Surface high pressure across the Southern Atlantic, extending into
the Southeast US coast, will remain nearly stationary through the
short-term period. This will make for a seemingly rare rain-free and
warm weekend. Skies should be clear for much of the weekend, with a
few periods of thin cirrus. Cloud coverage will increase a bit on
Monday with a slight uptick in upper level moisture, but still
expect some sunshine at times nonetheless. Each afternoon should
also bring a nice progressive sea breeze as the temperature
difference increases between land areas and the relatively cooler
shelf waters. Temperatures will be trending warmer through the
period as broad ridging aloft prevails and low level thickness
increases. Saturday will top out in the mid to upper 70s, increasing
to the upper 70s/low 80s Sunday, and the low to mid 80s for Monday.
Similarly, lows will trend warmer as Saturday night drops into the
low to mid 50s and Sunday night into the upper 50s/low 60s.

&&

.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
Ridging aloft, high pressure at the surface, and above normal
temperatures will continue through Tuesday. A cold front is then
expected to approach the forecast area from the west Tuesday night
and is currently progged to push offshore Wednesday evening. The
front looks quite progressive and should bring a quick shot of
showers and possibly isolated thunderstorms. Model guidance suggests
there will be plenty of deep layer shear, though very little
instability. So, it is possible there could be at least a low end
severe threat on Wednesday. Temperatures will cool back to near or
slightly below normal behind the front for the end of next week.

&&

.AVIATION /07Z FRIDAY THROUGH TUESDAY/...
VFR at KCHS, KJZI and KSAV through 06Z Saturday.

Extended Aviation Outlook: VFR conditions will prevail.

&&

.MARINE...
Today: High pressure will continue to build into the waters
this morning. With steady pressure climbs, and weak cold
advection, northerly winds will be as high as 15 or 20 kt, plus
some higher gusts. Conditions will be close to advisory
thresholds on the near shore waters south of Edisto. But not
enough for a Small Craft Advisory. Instead there is an advisory
for the outermost Georgia waters due to frequent gusts of 25 kt
or more, and seas still as high as 6 feet. A more relaxed
gradient develops this afternoon, allowing for sea breeze
circulations, and also the end of the advisory on the Georgia
waters beyond 20 nm out.

Tonight: High pressure remains firmly in control. Winds will be
a little higher on the Charleston County waters early on, with
lingering sea breeze influences and a slightly tighter gradient.
But after that, winds will be no more than 10 or 15 kt, mainly
out of the SW most of the night, with subtle land breeze
circulations late.

Saturday through Monday: Surface high pressure across the Southern
Atlantic and across the local waters will result in persistent
southwesterly winds through the period. Wind speeds will average 10-
15 kt, but will briefly surge higher at times as the sea breeze
develops each afternoon. Also, the gradient between the offshore
high and an inland surface trough will support stronger winds at
times. Marginal Small Craft Advisory conditions are expected in the
Charleston County nearshore waters for a brief period late Saturday
evening with gusts approaching 25 kt. Seas will mostly range 2-3 ft,
with some 4 footers further offshore.

Tuesday through Wednesday: Winds/seas will begin to increase/build
Tuesday ahead of an approaching cold front, which is currently
progged to push offshore Wednesday evening. Southwest gusts around
25-30 kt are possible across all marine zones, including the
Charleston Harbor, beginning Tuesday evening through at least
Wednesday. Seas around 3-6 ft will be common in the local waters as
well. Small Craft Advisories will likely be needed.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...Small Craft Advisory until 2 PM EDT this afternoon for AMZ374.

&&

$$

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


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