195
FXUS62 KCHS 300744
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
344 AM EDT Mon Sep 30 2024

.SYNOPSIS...
A broad area of Low pressure will persist over the region
through Tuesday. A dry cold front is forecasted to move through
the region later Wednesday, followed by cooler High pressure
through the rest of the work week. An area of Low pressure may
pass south of the region next weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
Today: Aloft, the forecast area will continue to sit in the
area between the large ridge to the southeast that stretches
from the eastern Gulf of Mexico and into the central Atlantic,
and the upper low near the central Appalachians. Through the
day, the upper low will start to make some eastward progress and
the flow pattern across the forecast area will increasingly
take on an anticyclonic curvature. At the surface, a weak area
of low pressure will slip into the central Carolinas with an
associated surface trough that will extend back into central
Georgia. This setup will continue to produce southwesterly flow
in the low- level across much of the region. The airmass will be
characterized by precipitable water values in the 1.25-1.50"
range, with model soundings depicting plenty of mid-level dry
air and warm temperatures. Such an environment will not be
particularly supportive of the development of showers, which is
supported by hi-res model output. Instead, shower development
seems more likely inland across the Midlands closer to the
aforementioned surface trough. The last day of September will
bring another warm day with above normal temperatures. Look for
highs in the upper 80s across the entire area.

Tonight: No change to the overall setup and quiet conditions.
There are no significant concerns for fog and lows are forecast
to range from the mid to upper 60s inland to the low 70s along
the coastal corridor.

&&

.SHORT TERM /TUESDAY THROUGH THURSDAY/...
Tuesday: The mid-levels will consist of a positively tilted
shortwave over the Southeast and Lower MS Valley in the morning.
It`ll slowly shift eastward during the day, with it`s axis
becoming located off the coast late at night. At the surface, a
broad area of Low pressure will be over or just north of our
region during the day, then shifting offshore overnight.
Additionally, a dry cold front will be approaching from the west
and northwest late at night. Though, it`s not expected to reach
our area during this time period. Just about all of the
synoptic models and long-range CAMs keep our area dry, with POPs
peaking around 10% along the immediate coast during the
afternoon. Despite mostly cloudy skies, thickness values support
temperatures well above normal. Highs will be in the mid to
upper 80s. Lows will range from the mid 60s far inland to around
70 degrees at the immediate coast.

Wednesday: A positively tilted mid-level trough will be located
off the Southeast U.S. in the morning. As it slowly moves
further offshore during the day and into the night, weak ridging
will gradually build over the Southeast. A dry cold front will
be located to our west and northwest in the morning. It`s
forecasted to move through our area during the late afternoon or
evening, then shift further offshore after midnight. High
pressure located to our north northwest will then build in
overnight. Given the lack of moisture, POPs peak at no more than
10% during the afternoon and with the frontal passage. Expect
some cumulus in the afternoon and evening, followed by clearing
skies after midnight. Some compression ahead of the front will
yield temperatures a few degrees above normal. Highs will be in
the mid to upper 80s. Lows behind the front will range from the
mid 60s far inland to around 70 degrees at the beaches.

Thursday: The mid-levels will consist of weak ridging over the
Southeast U.S. and the Mid-Atlantic States. At the surface, a
cold front will stretch off the Southeast U.S., and to our south
in the morning. Meanwhile, High pressure will be centered over
the Mid-Atlantic States. The cold front is forecasted to move
further away from us, pushed by the High that should shift off
the Mid-Atlantic Coast later in the day. Subsidence associated
with the High will keep our area rain-free. However, when the
High shifts offshore this will cause moisture and clouds to
start increasing from south to north during the late afternoon.
High temperatures should be in the low to mid 80s.

&&

.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
High pressure passing to our distant northeast will bring our
area dry conditions Thursday night. What happens Friday into the
weekend may hinge on the potential placement, timing, and
strength of a disturbance over the western Caribbean Sea. NHC
has highlighted this region in the Tropical Weather Outlook, so
refer to this product for the latest information. Likewise, NHC
and WPC collaborated the WPC Surface Fronts and Sea-Level
Pressure maps during this time period. They have Low pressure
tracking northward across the eastern Gulf of Mexico on Friday,
then northeastward on Saturday, and then nearing the western FL
coast by Sunday morning. As for us, our long term forecast is
the NBM.

&&

.AVIATION /08Z MONDAY THROUGH FRIDAY/...
VFR conditions are expected to prevail at KCHS, KJZI, and KSAV
through 06z Tuesday. There is a very small chance that an
isolated shower could impact KCHS or KJZI through about 10z.
Otherwise, quiet conditions are expected.

Extended Aviation Outlook: Mainly VFR. Periods of ground fog
could cause brief flight restrictions around dawn through
Friday.

&&

.MARINE...
Today through tonight: Southwest flow will turn a bit more due
southerly this afternoon and early this evening with the sea
breeze, before turning more westerly late tonight. Wind speeds
will generally top out in the 10-15 knot range. Seas will
average 2 ft, but could be up to 3 ft at times beyond 20 nm.

A broad area of Low pressure will be over or just north of our
waters Tuesday, then shifting offshore Tuesday night. A dry cold
front will approach from our west and northwest Wednesday
morning. It`s forecasted to move through our waters Wednesday
evening, then shift further offshore after midnight. High
pressure located to our north northwest will then build in
Wednesday night, passing to our north on Thursday, then moving
off the Mid-Atlantic Coast Thursday night. An area of Low
pressure may pass south of our region next weekend. Despite all
of these synoptic features, winds and seas are expected to
remain below Small Craft Advisory criteria through the end of
the work week.

&&

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

&&

$$

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