Area Forecast Discussion
Issued by NWS Charleston, SC

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901
FXUS62 KCHS 160607
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
207 AM EDT Wed Jul 16 2025

.SYNOPSIS...
Atlantic high pressure will prevail through early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Today: Aloft, the east to west oriented ridge axis will
continue to extend into the GA/SC coast. At the surface, The
subtropical high will be the primary feature and will drive the
low-level flow pattern across the forecast area. Overall, today
does not look particularly active for convection. The ridge
aloft will help to keep coverage down, and model soundings are
rather warm and only depict MLCAPE values of up to around 1,500
J/kg. Instead, we will likely continue to see weak convection
push onshore from the coastal waters within the onshore flow
throughout much of the day. Any diurnal land-based convection
that develops also looks to be weak and not a severe threat.
Also, the locally heavy rain threat is low thanks to the
progressive nature of this convection with storm motion on the
order of 15-20 mph. Temperatures are forecast to top out in the
low 90s, with heat indices mostly in the low 100`s and some
isolated values into the mid 100`s.

Tonight: Overall, little change to the pattern overnight. Any
lingering land-based convection should dissipate through the
early evening, though there will still likely be some shower
activity over the coastal waters trying to push onshore at
times. The low-level flow will start to become more south-
southwest or southwest with time which should keep most of the
nocturnal convection across the coastal waters off the coast.
Similar lows to the last few nights, with temperatures falling
into the low to mid 70s inland and hanging around in the upper
70s along the coast.

&&

.SHORT TERM /THURSDAY THROUGH SATURDAY/...
A strong deep layered ridge will prevail Thursday through
Saturday, bringing hot and humid conditions. Friday and Saturday
will feature highs in the mid/upper 90s, dewpoints in the
mid/upper 70s, and heat indices topping 108 in some places. We
could need Heat Advisories for part of the area both days. An
increase in upper level subsidence will limit PoPs to 20-30%.

&&

.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
The upper ridge axis will shift west of the area late in the
weekend into early next week, allowing some shortwave energy to
rotate in from the north. This could result in an increase in
diurnal convection coverage Monday and Tuesday. Toasty
conditions will continue into Monday, with possible Heat
Advisories both days. Temps may cool slightly by Tuesday.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
The 06z TAF period begins with VFR conditions at KCHS, KJZI,
and KSAV. The main issue for through sunrise will be shower
activity moving onshore and possibly producing brief periods of
MVFR conditions. Over the next few hours, the best chances are
expected to be around KSAV. Then around sunrise and through mid
morning, the focus for shower activity should shift up more into
the KJZI and KCHS area. By the early afternoon, most of the
shower activity should shift inland of the terminals. Winds will
be a bit stronger today with some gusts into the 16-20 knot
range expected.

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: Subtropical high pressure to the east will
be the primary feature driving the flow across the local waters
through the period. Winds today will be southerly with speeds
mostly in the 10-15 knot range, though there could be an
occasional 20 knot gust. Overnight, winds will slightly start to
veer around to become more south-southwest late. Speeds should
be the same, mostly 10-15 knots with occasional gusts up to 20
knots. Seas should average 3-4 feet through the period. We will
likely continue to see isolated to scattered showers and
thunderstorms across the coastal waters today within the onshore
flow. This activity isn`t expected to be particularly strong
and there is a low probability of strong wind gusts.

High pressure will prevail Thursday through Monday, maintaining
typical summertime weather in the marine area. No headlines
expected.

&&

.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