863
FXUS62 KCHS 151043
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
643 AM EDT Thu Aug 15 2024

.SYNOPSIS...
High pressure will build in from the north through late week.
Another cold front may approach the area early next week, then
remain nearby through late week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Spotty showers continue to move through the southern marine
zones and into a small portion of southeast Georgia around
McIntosh County. Forecast has been updated to extend isolated
pops across that area through the morning.

Previous discussion...
Overnight composite analysis reveals upper level ridging stretching
from the Great Lakes to the Gulf coast and a downstream trough
axis off the southeast coast. Large expanse of surface high
pressure and a drier air mass covers much of the eastern CONUS.
Gradient of higher low level theta-E air stretches off the
Atlantic into southeast Georgia with spotty showers just
clipping the far southern part of the forecast area early this
morning.

Surface high pressure will further expand into the southeast
through tonight while northeasterly flow continues to reinforce
cooler/drier air across the region. Thus, overall quiet weather
is anticipated along with more comfortable conditions. That
said, high-res guidance does show some isolated showers popping
across southeast Georgia this afternoon. But, given minimal
instability and strong capping around 750 MB noted in forecast
soundings, keeping with a dry forecast, except for a small area
of pops this morning across McIntosh County.

Highs today will run 86-90F with slightly cooler readings along
the coast. Lows tonight will run from the middle 60s to near 70,
warmer along the coast.

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY/...
Friday: Aloft the region will remain along the eastern periphery of
high pressure centered over Texas. A mid-level low pressure center
will be positioned just to the west of the Great Lakes, while to the
east Tropical Cyclone Ernesto remains well off of the SE coastline.
Surface high pressure will be directly overhead on Friday, yielding
a dry forecast with highs in the upper 80s to around 90. Overnight
temperatures will be a little cooler, with upper 60s in many
locations and around 70 at the beaches.

Saturday and Sunday: Slight ridging aloft will develop along the
southeastern coastline through the weekend as the region becomes
pinched between the low pressure over the Great Lakes and Tropical
Cyclone Ernesto. High pressure will remain the dominant synoptic
feature at the surface, however a weak cold front will approach from
the west on Sunday. Dry conditions are forecast on Saturday, however
rain chances increase into Sunday as the weak cold front approaches.
High temperatures both days are forecast to reach into the low 90s,
with overnight lows in the low to mid 70s.

&&

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
Broad troughing aloft will develop late Sunday and into early next
week along the Eastern Seaboard as the aforementioned area of low
pressure over the Great Lakes pushes towards the NE. At the surface
a weak cold front is progged to impact the region early in the work
week. Even with the weak cold front, PoPs are limited to around 30-
40% each afternoon. Temperatures are forecast to remain right around
normal through the period.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
VFR conditions are expected to prevail at KCHS, KJZI, and KSAV
through 12z Friday.

Extended Aviation Outlook: Surface high pressure will yield VFR
conditions through Saturday. A cold front is forecast to impact the
region late this weekend/early next week, bringing the risk of brief
flight restrictions.

&&

.MARINE...
Today: Surface high pressure will center across the coastal
plain of SC/NC with winds out of the E/NE 10 to 15 kt. Wind
gusts up to 20 kt are likely with conditions remaining below
Small Craft Advisory criteria.

Friday through Tuesday: Surface high pressure will begin to shift
away from the local marine waters on Friday, with winds shifting
from the NE in the morning to the E/SE by the evening hours. Swell
from Tropical Cyclone Ernesto will begin to impact the region on
Friday, with seas reaching 5 to 6 ft out to 20 nm, and 6 to 7 ft out
to 60 nm in SE GA. Small Craft Advisories will likely be required
for all marine zones outside of the Charleston Harbor. These Small
Craft Advisories may linger into Saturday as swell continues to
impact the region. By Sunday the region should be clear of all
advisory conditions, with winds generally around 10 to 15 knots,
increasing in speed along the coastline in the afternoon hours with
the sea breeze circulation.

Rip Currents: Long period swell (13 to 15 seconds) from Tropical
Cyclone Ernesto is forecast to reach the forecast area on Friday.
This in combination with onshore winds will produce a high risk of
rip currents at all area beaches on Friday. The threat for rip
currents could persist into Saturday as well.

&&

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

&&

$$

NEAR TERM...TBA
SHORT TERM...CPM
LONG TERM...CPM
AVIATION...TBA/CPM
MARINE...TBA/CPM