844
FXUS62 KCHS 171944
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
344 PM EDT Tue Jun 17 2025

.SYNOPSIS...
High pressure in the Atlantic will prevail across the Southeast
this week. A cold front could approach, then pass just to our
north later this week.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
We`ll remain on the western side of a strong deep layered ridge
through tonight. The cumulus field has been notably suppressed
so far this afternoon due to the mid-level cap. Isolated showers
or a thunderstorm could pop up along the sea breeze or farther
inland within the lee trough, but coverage will be very limited
and anything that does develop should die off by early evening.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
The mid-levels will consist of a broad 594 dam High located off the
Southeast U.S. coast Wednesday morning. Its western periphery
will stretch into our area through Thursday morning. By later
Thursday, the High will get pushed offshore by a trough that`ll
stretch from the Great Lake Region down into the Deep South.
This trough will pass over the spine of the Appalachians
Thursday evening, then the East Coast early Friday morning,
before moving offshore by late Friday. At the surface, High
pressure will prevail in the Atlantic this week, with its
western periphery stretching into our area. A cold front should
approach from the northwest Thursday night, then either brush or
pass just to our north on Friday. This synoptic pattern will
usher PWATs >1.75" across our area. High temperatures will be in
the lower to middle 90s each day. Though, it`ll be cooler at
the beaches due to the sea breeze. Heat indices will also be
above 100 degrees. The combination of heat and moisture will
generate a decent amount of instability and DCAPE, with both
looking to trend higher each day, and possibly being the highest
on Friday. Shear should be modest each day. The deterministic
models have a typical summertime convective pattern in place
during the short term, with isolated to maybe scattered
convection along the sea breeze on Wednesday, then scattered
convection on Thursday, and possibly the highest coverage on
Friday, due to the proximity of the front. For this reason the
SPC has part of our area under a Marginal Risk of severe
thunderstorms on Friday. As for the severe potential, strong to
marginally severe pulse storms are possible on Thursday, with
Friday potentially being the most likely day in the short term.
The main threat would be damaging winds. Locally heavy downpours
are also a concern, especially if the storms are slow moving
and train. The convection should decrease in both intensity and
coverage during the evening, with only a stray shower possible
each night. Lows will be mild, generally the 70s.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
The aforementioned front dissipates into the weekend, with High
pressure remaining in the Atlantic. Expect diurnal convection to
persist throughout the long term time period. Temperatures should
remain in the lower to middle 90s with heat indices topping out in
the 100-105 degree range.

&&

.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
VFR.

Extended Aviation Forecast: Brief flight restrictions are possible
in showers and thunderstorms, mainly each afternoon and early
evening.

&&

.MARINE...
S to SW flow around 15 kt will continue through tonight as we
remain in the western periphery of Atlantic high pressure. A
decent sea breeze this afternoon into early this evening could
produce a few gusts in Charleston Harbor above 20 kt.

High pressure will prevail in the Atlantic this week, with its
western periphery stretching into our coastal waters. A cold
front should approach from the northwest Thursday night, then
either brush or pass just to our north on Friday. Expect a
typical summertime wind pattern. Each day, winds should back
with the formation of the afternoon sea breeze. The strongest
winds will be along the land/sea interface and across the
Charleston Harbor (with its passage). Each night, winds will
veer and increase as the nocturnal jet sets up, especially
closer to the coast. Wind gusts could briefly hit 25 kt at times
through Friday, so we can`t rule out Small Craft Advisories for
some of the marine zones. Seas will generally peak in the 3-4
ft range.

&&

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

&&

$$

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