441
FXUS62 KCHS 130548
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
148 AM EDT Sun Jul 13 2025

.SYNOPSIS...
Weak high pressure will continue to build across the region
through the week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Today: Aloft, the center of the upper ridge will be situated
just off to the southwest of the forecast area with the ridge
axis extending up through north GA and into the Southern
Appalachians. At the surface, the forecast area will be situated
within a baggy trough that extends from a surface low
positioned off the Mid Atlantic coast. This setup will actually
provide northwest to north flow through the column today,
yielding an uncommon storm motion of north to south. Concerning
thunderstorms, model guidance again suggests that coverage won`t
be overwhelming but the same threats apply as the last few
days. The setup featuring northwest surface flow should work to
keep the sea breeze pinned closer to the coast in the afternoon,
meaning that convective initiation should favor the immediate
coastline as well. In fact, there is some agreement that
convection will initiate generally across eastern Berkeley and
Charleston counties in the early to mid afternoon, push to the
south, and also throw out outflow boundaries that will move to
the south and southwest and drive additional development down
the coastline into the early evening hours. The area along and
east of I- 95 will remain within a slot of deep moisture and
precipitable water values of 2-2.2 inches. Warm and moist
profiles will again yield a rather modest severe environment,
with the main threat being wet microbursts that occur in
conjunction with the best boundary interactions. The heavy rain
threat remains the same as well, where locations directly
impacted by thunderstorms could see 1-2 inches of rain.

It will also be a warm and humid day with high temperatures
expected to top out in the mid to upper 90s for much of the
area. The highest dewpoints are expected to be generally along
and east of I-95, peaking in the mid to upper 70s. This should
yield heat index values on the order of 100-105 degrees, just
below Heat Advisory criteria. Another limiting factor should be
the development of thunderstorms in the early to mid afternoon
which will disrupt peak heating for portions of the area.

Tonight: The best coverage of showers and thunderstorms should
shift down the coast and into southeast Georgia through the
early to mid evening hours. Some convection could linger into
the early morning hours depending on how outflow boundaries
progress. But overall, land areas should be dry late in the
overnight while the coastal waters become more active.
Otherwise, a pretty standard summer night with lows only in the
mid 70s for much of the area.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
A weak upper level ridge will remain over the Southeast Monday
into Tuesday before weakening. Meanwhile Bermuda high pressure
will prevail at the surface. A relatively typical July pattern
will continue, albeit with slightly greater diurnal convective
coverage. Deep moisture and moderate instability will support
locally heavy rainfall with any shower or thunderstorm that
develops, and isolated severe thunderstorms are also possible.
Above normal temperatures expected Monday, particularly far
inland where highs will climb into the upper 90s. Near-normal
highs expected Tuesday and Wednesday.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
A deep layered ridge will develop over the Southeast late week
into the weekend, producing typical summertime weather. Ample
moisture and instability should allow scattered convection each
day, primarily seabreeze-driven.

&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
The 06z TAF period begins with VFR conditions at KCHS, KJZI, and
KSAV. There could be an area of low stratus that develops across
interior southeast SC closer to sunrise and there is a chance it
builds into KCHS. For now we think it will stay just inland, and
we have kept the forecast VFR. Otherwise, the main concern for
the TAF period will be thunderstorms later this afternoon and
evening. We have maintained the TEMPO groups at all 3 sites,
starting at 20z at KCHS, 21z at KJZI, and 22z at KSAV. Heavy
rain and gusty winds will be the main threats, possibly
producing a brief period of MVFR or IFR conditions.

Extended Aviation Outlook: VFR will mainly prevail throughout
the period, however brief flight restrictions are possible
within showers and thunderstorms that develop in the afternoon
and/or evening hours.

&&

.MARINE...
Today and tonight: Overall, continued quiet and well below
Small Craft Advisory conditions for the local waters. West-
northwest or northwest winds this morning will be quite weak,
with speeds topping out 5-10 knots. For the afternoon and
evening, winds will flip around to become southerly under the
influence of the sea breeze circulation with speeds still mostly
10 knots or less. Right along the land/sea interface speeds
could top out in the 10-15 knot range, including Charleston
Harbor. Then overnight, winds will continue to be quite weak,
diminishing to less than 10 knots. Seas should average around 2
feet, but could be up to 3 feet around the 20 nm line and
beyond. Much like the last few days, thunderstorms are expected
to develop along or just inland of the coast and then move
southward to the coast or out over the coastal waters. Frequent
lightning and strong wind gusts will be the primary threats.

A persistent southerly flow will continue over the waters
Monday through Thursday as high pressure sits offshore. A
moderate sea breeze will develop each afternoon, with wind gusts
in Charleston Harbor occasionally topping 20 kt. No headlines
currently anticipated.

&&

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

&&

$$

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