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000
FXUS62 KCHS 120527
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
127 AM EDT Fri Apr 12 2024

.SYNOPSIS...
A cold front will move through the area tonight. High pressure
will gradually build across the region late this week and
persist through next week.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
Early this morning: Radar imagery shows the line of showers
along the initial front now pushing off the Charleston County
coast. The rest of the night will be dry and the main forecast
focus will be on winds. We are seeing a nice punch of westerly
winds move through the area now. KSAV recently reported a peak
wind gust of 39 knots and KCHS has just recently start to gust
around 30 knots too. This window of stronger winds will pass
through over the next hour or two and winds should settle down
with gusts to around 20 knots being more common to around
sunrise. An area of cloud cover, a mix of low and mid clouds, is
also working through from west to east. We should see clear
skies for the entire area by around 5 am or so. Lows still
forecast to mostly fall into the mid 50s inland and the upper
50s along the coast.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY/...
Friday: A broad trough will exist both surface and aloft, with
a weak short wave to pass through midday, and another and
stronger one to brush by to the north late. With so much dry air
in place, this will produce no more than a few stratocumulus or
flat cumulus. Full insolation and a deep downslope flow will
result in max temperatures in the lower and middle 70s, in line
with the low level thickness forecast blended with the MOS and
NBM guidance. Deep mixing and a packed pressure gradient will
result in breezy to windy conditions. Highest winds will peak at
25-35 mph, or even a little higher on elevated bridges. Not
quite enough for a Wind Advisory, but certainly enough for a
Lake Wind Advisory on Lake Moultrie.

Friday night: Gusty winds will fade during the early evening,
but never fully decouple. High pressure gradually builds in from
the west, and with clear skies and weak cold advection, we`ll
see lows getting down to mid and upper 40s inland, 50-55F
degrees closer to the Atlantic. Any Lake Wind Advisory on Lake
Moultrie that is issued will come down early at night.

Saturday: High pressure will be situated along the northern
Gulf of Mexico coast, with a trough near the Appalachians. The
trough aloft edges into the ocean, as ridging to the west is
working its way eastward. There`s still some gustiness to the
winds, but much less than recently; peaking around 20 or maybe
25 mph. Full sunshine and another day with a downslope flow will
equate to max temperatures very similar or a tad warmer than
Friday.

Sunday: Zonal flow will prevail aloft, with an upstream short
to approach late. However, it doesn`t have any moisture to work
with, so no impacts. Higher heights aloft, 805 mb temperatures
climbing to 12-13C, and the low level thickness as much as
1390-1395 meters will support an even warmer day. We have lower
80s just about everywhere away from the coast, where local sea
breeze influences will hold temperatures down in the 70s.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
A 5910-5920 meter anticyclone in the Gulf of Mexico will expand
across the local counties early to mid week, with heights
across our area climbing near or even above the 90th percentile.
That along with 850 mb temperatures that are also near or
greater than the 90th percentile, and Atlantic high pressure at
the surface to dominate, will support temperatures far into the
80s each afternoon away from the beaches. No records, but about
5-10F degrees above normal. With more of a southerly synoptic
flow to develop, night time lows will also be some 5-10F degrees
above climo.

&&

.AVIATION /05Z FRIDAY THROUGH TUESDAY/...
An area of clouds will pass through KCHS, KJZI, and KSAV between
06-08z. There could be a brief period of MVFR ceilings, but
it should be very shortlived if it happens at all. Winds will
also be at their peak in the 06-08z time period, with gusts into
the 30-35 knot range. They should calm down thereafter, with
gusts in the 20-25 knot range more common through sunrise.
Friday will bring a VFR day with gusty west winds. Frequent
gusts into the 25-30 knot range are expected.

Extended Aviation Outlook: VFR.

&&

.MARINE...
Tonight: Buoys and ship reports observed marginal Gale Warning
conditions across the marine zones late this afternoon. These
conditions will likely remain through early this evening. A cold
front is timed to sweep across the marine zones late this
evening. In the wake of the front, winds will veer from the WSW
and strengthen with gusts between 35-40 kts. The gusty
conditions should continue across the marine zones until the
pre-dawn hours Friday. The Gale Warnings were extended later
into tonight to highlight the post-frontal wind surge. Seas this
evening should range between 6-10 ft, decreasing to 4 to 8 ft
late tonight.

Friday: Solid Small Craft Advisory conditions will exist across
all waters, with a pinched gradient in place due to a broad
surface trough across the immediate waters. Wind gusts will
reach close to 30 kt at times, but with the offshore
trajectories, seas that are initially as high as 5-7 feet, will
slowly start coming down through the day. Waves will be at least
near 2 feet in Charleston Harbor.

Friday night and Saturday: There is still enough of a gradient
between a broad trough to the north and northeast, and high
pressure to the southwest, that we still might require Small
Craft Advisories, especially on the Charleston County Atlantic
waters, and the Georgia waters beyond 20 nm offshore.

Saturday night through Monday night: Finally much better marine
conditions, with high pressure stretching over or to the south
of the area from the Gulf of Mexico into the Atlantic. Although
there could be some locally higher winds due to the sea breeze,
on average the wind speeds will be 15 kt or less, and seas no
greater than 2 to 4 feet.

High Surf: Large breaking waves are expected to develop at the
beaches today, highest along the Charleston county coast. A High
Surf Advisory is in effect until 8 AM Friday.

Rip Currents: There might be just enough swell energy to
produce a Moderate Risk of Rip Currents at area beaches on
Friday.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...Lake Wind Advisory until 7 PM EDT this evening for SCZ045.
     High Surf Advisory until 8 AM EDT this morning for SCZ050.
MARINE...Gale Warning until 6 AM EDT early this morning for AMZ330-352-
     354-374.
     Gale Warning until 8 AM EDT this morning for AMZ350.

&&

$$

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