020
FXUS62 KCHS 231414
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
1014 AM EDT Mon Jun 23 2025

.SYNOPSIS...
High pressure will remain across the Southeast U.S. for the
first half of this week, then slowly shift over the Atlantic
thereafter. Hot and humid conditions are expected throughout
the week with rain chances increasing by the second half of
week as surface troughing begins to form over the region.

&&

.NEAR TERM /THROUGH TONIGHT/...
Late this morning: Overall, no changes to the forecast for
today. The area will sit just to the south of a prominent mid
and upper level ridge centered near the Mid Atlantic region. At
the surface, the subtropical high will extend into the area and
leave us with a typical summer-like pattern. Large-scale
subsidence under the influence of the ridge is expected to keep
the area convection-free through the day. However, it is summer
and you can never completely count out an isolated shower or
thunderstorm. If a shower or storm were to develop, it would
likely be with the afternoon sea breeze closer to the Tri-County
region where higher dewpoints pool just behind the boundary.
But, we have kept the forecast dry for now. Low-level thickness
values off the 12z KCHS RAOB support mid 90s away from the
immediate coast. Fortunately, dewpoints are expected to mix out
into the upper 60s inland which will help keep heat index values
from getting out of the 100-102 degree range. We could see some
values around 105 in the Charleston Tri-County region for a
brief period this afternoon with the higher dewpoints behind the
sea breeze boundary.

Tonight: No significant changes are expected to the overall
pattern in regards to high pressure dominating the weather
pattern across the Southeast. Sfc winds will likely decouple
under clear skies for areas away from the beaches mid-late
evening, with the bulk of the area experiencing light/calm winds
during the second half of the night. Hires guidance depicts
considerably less fog potential across the local area late, but
perhaps some shallow ground fog across Southeast Georgia a few
hours prior to daybreak, mainly near the I- 95 corridor closer
to the Altamaha River, where lower condensation pressure
deficits reside. Temps will remain mild, with lows generally
ranging in the lower 70s inland to mid-upper 70s closer to the
coast and across Downtown Charleston.

&&

.SHORT TERM /TUESDAY THROUGH THURSDAY/...
A strong upper-lvl ridge continues to build over the
Southeastern CONUS throughout the week. According to model
guidance, 500MB heights on Tuesday will be ~598 dam, and then
weaken to ~594 over the next couple days. While these are very
high heights for the region, the highest heights will remain
just to the north. However, this will still produce a strong
warming trend for the next couple of days. Temperatures will
climb into the mid to upper 90s on Tuesday and Wednesday, with
heat indices creeping ~105-107 in the afternoons. As of right
now, heat indices remain just below Heat Advisory criteria
(108F), but this will continue to be monitored. This sort of
heat is not uncommon for this time year, however it is important
to remember to stay hydrated and limit outdoor activity (esp.
in the afternoon). With little moisture available and subsidence
filtering into the mid-lvls on Tuesday, this will keep the
forecast fairly dry and uncomfortably hot. Tuesday actually
looks to be the hottest day of the week with temperatures making
a run for the 100 degree mark. Some of the models have been
hinting that a weak surface trough could form over the region
sometime on Wednesday and allow for a cooler day than expected
on Thursday with temperatures reaching into the low 90s.
Simultaneously, this feature might advect enough moisture into
the region to allow for some showers and thunderstorms to
develop in the afternoon along the seabreeze on Wednesday and
Thursday. Thus, 20-30% PoPs were added in the forecast for
Thursday and Wednesday afternoon. Overnight lows will remain
mild and only dip into the low to mid 70s.

&&

.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
This strong upper-lvl ridging pattern will finally begin to
weaken by the end of the week as a weak surface trough tries to
form over the region. This will allow for some moisture to
return and some recent ensembles indicate a better chance for
rain over the weekend and into early next week. Temperatures
will remain above normal for this time of the year into the
weekend.

&&

.AVIATION /14Z MONDAY THROUGH FRIDAY/...
VFR conditions are expected at CHS/JZI/SAV terminals through
12Z Tuesday. Shallow ground fog will be possible near KSAV near
the end of the TAF period, but probabilities are too low to
include MIFG in the latest TAF issuance.

Extended Aviation Outlook: With the strong upper-lvl ridge in
place over the Southeast, VFR should mainly prevail throughout
the period. However, there could be brief flight restrictions in
the afternoon hours starting on Wednesday through the end of
the week as rain chances make a return.

&&

.MARINE...
Today and Tonight: Atlantic high pressure will dominate the
pattern across local waters, favoring conditions that remain
well below Small Craft Advisory levels through tonight. In
general, west/southwest winds in the 5-10 kt range this morning
will turn south-southeast and peak around 10-15 kt this
afternoon, highest across the Charleston Harbor and perhaps
along beaches as a sea breeze develops, then shifts inland.
Winds should then turn more southwest by late evening, remaining
around 10 kt or less overnight. Seas will generally range
between 1-2 ft.

Tuesday through Friday: As a weak south-easterly swell
continues to filter in, seas will be 1 to 2 ft and then
gradually become 3 to 4 ft on Friday afternoon as a more
easterly, stronger swell mixes in. Expect winds at 5 to 10 kt to
prevail throughout the period as this upper-lvl ridge continues
to sit over the region. However, by second half of the week,
this ridge will begin to shift offshore as a weak surface trough
scoots its way into the Southeast. It could become a bit gusty
each afternoon with gusts up to 15 to 20 kt as the seabreeze
pushes inland (gusts strongest across the immediate coastline
and the Charleston Harbor).

Rip Currents: A 1.5 to 2 ft, 8 second swell will impact the
beaches through this evening along with a 10-15 kt onshore wind
in place. Given these conditions are similar to yesterday with
several rip currents reported along Tybee Island, GA, a Moderate
Risk for rip currents is in place along Georgia beaches through
this evening.

&&

.TIDES/COASTAL FLOODING...
The new moon is Tuesday night, which will yield higher
astronomical tides. Winds should be from the SW, which would
limit tidal anamolies. So while Coastal Flooding (mainly for the
Charleston tide gauge) is not forecasted at this time, it won`t
take much for it to occur, prompting an advisory.

&&

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

&&

$$

NEAR TERM...BSH/DPB
SHORT TERM...Dennis
LONG TERM...Dennis
AVIATION...Dennis/DPB
MARINE...Dennis/DPB