158
FXUS62 KCHS 232005
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
405 PM 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 /UNTIL 6 AM TUESDAY MORNING/...
This evening and tonight: Still can`t rule out an isolated
shower or thunderstorm developing in the early evening hours,
but we continue to advertise a dry forecast. Overall, another
very quiet night is expected as the sea breeze steadily marches
inland through the evening. There could be a little shallow
ground fog across southeast GA closer to sunrise, similar to
last night and mainly south of I- 16. However, no significant
visibility reductions are expected. Lows are forecast to fall
into the low to mid 70s.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
The strong ridge of high pressure continues into Tuesday, with
both the NAEFs and ECMWF ensemble situational awareness tables
showing the 500 mb heights are at climatological maxes for this
time of year. At the surface, a weak high pressure moves across
the area keeping winds light in the morning, increasing out of
the east behind the sea breeze as the high continues to drift
southwards. As a result of the climatologically high 500 mb
heights, 700 mb to 1000 mb temperatures are at or above the 90th
percentile of climatology. Expect widespread upper 90s to lower
100s (lower to mid 90s along the coast) for max temperatures in
the afternoon. Similar to what we saw today, Tuesday will start
off with dewpoints in the lower to mid 70s, dropping into the
upper 60s to lower 60s as mixing commences. However, given the
warmer temperatures, heat index values of 106 to 110 are
expected throughout the afternoon hours. Have thus issued a heat
advisory for all of southeastern South Carolina, and majority
of southeastern Georgia, while the final three zones may have to
be included with the next forecast package. Shortly after peak
heating has been reached, convective temperatures are also
expected to be met resulting in very scattered thunderstorms
becoming possible, though the warm mid-levels resulting in a
weak cap has kept pops below 20 percent.

The strong aforementioned ridge begins to break down overnight
into Wednesday, and further more into Thursday as a weak upper
level disturbance moves from east to west across Florida. This
will result in a slow cooling trend for Wednesday where max
temperatures are again expected in the mid to upper 90s, though
chances for rain and increased cloud coverage as the sea breeze
forms and moves ashore decreases confidence in temperatures. If
current forecast holds, afternoon heat index values may again
make a run for mid to upper 100s, so there is potentially a need
for another heat advisory for Wednesday. On the other hand, if
chances for thunderstorms increases, 1500-2500 J/kg of CAPE
could lead to isolated chances for severe weather. SPC has the
region highlighted by a level 1 out of 5 risk for severe
thunderstorms. Thursday will be a touch cooler in the upper 80s
along the coast and lower 90s inland, as the Atlantic surface
high pressure forms well off to our east. Expect another round
of thunderstorms to be possible as the sea breeze pushes ashore,
and again given 1500-2500 J/kg of CAPE severe thunderstorms
cannot be ruled out.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
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 /19Z MONDAY THROUGH SATURDAY/...
VFR conditions will prevail at KCHS, KJZI, and KSAV through 18z
Tuesday. Shallow ground fog will be possible near KSAV in the
10-12z time period and we have added this to the TAF. No flight
restrictions expected.

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...
Tonight: Winds will peak early in the evening along the
land/sea interface with speeds 10-15 knots. Winds will then
gradually turn more westerly through the night in the 5-10 knot
range as a land breeze develops again. Seas are expected to
average around 2 feet.

Tuesday through Friday: At the surface, a weak high pressure
moves across the area keeping winds light in the morning,
increasing out of the south and east behind an afternoon sea
breeze. Will likely see gusts into the upper teens to lower 20s,
though small craft advisory criteria are not expected to be
met. After that, aside from diurnally driven showers and
thunderstorms, no marine concerns with greater than 50 percent
confidence at this time.

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...
Astronomical tides will peak with the evening high tide cycle
tonight, Tuesday night, and Wednesday night around 6.5 ft MLLW
at Charleston. Afternoon winds will only be marginally
supportive of increasing tidal departures each day. The evening
high tide will likely peak around 6.8-6.9 ft MLLW each evening,
falling just short of Coastal Flood Advisory criteria.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...Heat Advisory from 1 PM to 8 PM EDT Tuesday for GAZ087-088-
     099>101-114>119-138.
SC...Heat Advisory from 1 PM to 8 PM EDT Tuesday for SCZ040-042>045-
     047>052.
MARINE...None.

&&

$$

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