030
FXUS62 KCHS 192205
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
605 PM EDT Thu Sep 19 2024

.SYNOPSIS...
An area of high pressure is expected to gradually strengthen
across the region through early next week. A weak cold front
may approach from the west by next Thursday.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
Ongoing shower activity will dissipate pretty quickly after
sunset, possibly lingering a tad longer over parts of the
Charleston Tri-County into Colleton County. The boundary layer
will once again decouple quickly after sunset resulting in calm
to light/variable winds. The best fog parameters look to setup
across parts of Southeast Georgia again tonight, although 1000
hPa condensation pressure deficits look marginal. The mention of
"patchy fog" was expected a bit into interior Southeast South
Carolina with a mention of "areas of fog" over parts of
interior Southeast Georgia where the axis of best fog
parameters look to align. Lows from the upper 60s inland to the
lower 70s at the beaches and Downtown Charleston.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
Friday: The axis of the mid-level trough is expected to push
east over the western Atlantic as strong ridge centered over TX
ridges NE over the Ohio River Valley. GFS indicates that a short
wave is expected to track from north to south across the
forecast area during the afternoon, followed by rising heights.
As temperatures reach the mid to upper 80s over dewpoints in the
70s, weak instability should develop across extreme SE GA.
Latest run of the HREF indicates that a weak sea breeze may
develop along the GA coast Friday afternoon. The combination of
the shortwave passage, weak sea breeze, and limited instability
may support isolated showers along the coast of SE GA during the
afternoon.

Saturday and Sunday, the forecast area will become dominated by
weak sfc high pressure as a large H5 ridge builds across the
Deep South and Southeast U.S. GFS forecast soundings indicate
that the environment will remain less than 1.6 inches of PW with
a significant inversion at H8. High temperatures should favor
values in the upper 80s, with low 90s possible across inland GA
on Sunday. PoPs will remain less than SCHC through this weekend.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
Monday through Tuesday: Long term guidance indicates that the
H5 590 DM ridge will shift east across the northern Gulf coast
and FL. This ridge combined with a low over the western
Caribbean could set up a Rex Block through early next week. H5
heights should increase across the forecast area, peaking Monday
and Monday night, limiting any instability across the forecast
area on Monday and Tuesday. The forecast will feature dry
weather through early next week. High temperatures are forecast
to remain in the mid to upper 80s.

Wednesday: H5 heights will begin to break down, possibly with
the approach of amplifying wave. GFS shows a cold front
accelerating east, possibly pushing across the forecast area by
Wednesday evening. The forecast will feature SCHC to CHC PoPs
for showers and thunderstorms. High temperatures will generally
range in the mid 80s.

&&

.AVIATION /22Z THURSDAY THROUGH TUESDAY/...
20/00z TAF Discussion:
KCHS/KJZI/KSAV: Another round of fog/stratus will impact the
area tonight. The bulk of this should remain west of the
terminals with VFR conditions prevailing. The risk for MVFR
vsbys in fog is highest at KSAV and KJZI. The fog will mix out
quickly after sunrise.

Extended Aviation Outlook: No significant weather expected.

&&

.MARINE...
Tonight: Easterly winds late the afternoon and evening will
become northerly late tonight. Winds generally remain 10 knots
or less with seas averaging 1 to 3 feet.

Friday through Monday: Building high pressure should result in winds
between 10-15 kts with gusts around 20 kts. Wave heights should
generally remain between 2-5 ft. Conditions should remain below
Small Craft Advisory criteria.

&&

.TIDES/COASTAL FLOODING...
Given high astronomical tides and latest tidal departures, minor
coastal flooding is expected along the Charleston and Colleton
county coasts with the evening high tide cycle. A Coastal Flood
Advisory has been issued with tide levels expected to peak between
7.3-7.5 ft MLLW. Further south and along the Georgia coast, current
forecast keeps tides from reaching minor flooding criteria of 9.5
ft MLLW in Fort Pulaski, but will continue to monitor trends.

Positive tidal anomalies along with high astronomical tides from the
full moon will lead to elevated tides for the rest of this week and
through the weekend. Coastal Flood Advisories will probably be
needed for both the morning and evening high tides through Friday
for both Charleston Harbor and Fort Pulaski.

The astronomical high tides start to lower Saturday and Sunday, but
the morning high tides will likely be elevated enough to still
require Coastal Flood Advisories (especially for Charleston and
coastal Colleton Counties). More uncertainty exists for Fort
Pulaski.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...Coastal Flood Advisory until midnight EDT tonight for SCZ049-
     050.
MARINE...None.

&&

$$