Hilton Head Island, South Carolina 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

167
FXUS62 KCHS 230543
AFDCHS

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

.SYNOPSIS...
High pressure will remain across the Southeast U.S. the first
half of this week, then shift into the Atlantic for the second
half of the week. Surface troughing should form over the region
the second half of this week.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
Rain-free conditions will persist overnight, although an
isolated shower/tstm could develop closer to the west wall of
the Gulf Stream early Monday. It will remain warm tonight with
lows dropping into the lower 70s inland to around 80 at the
beaches and Downtown Charleston. Light/calm winds will prevail
away from the beaches through the night, which could allow a
few spots to drop into the upper 60s where radiational cooling
is locally maximized, but these instances should be pretty
isolated. Some shallow ground fog could develop just before
daybreak, mainly south of I-16, but also into the far southern
South Carolina counties where condensation pressure deficits are
low. No major reductions in visibilities are expected.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY/...
The mid-levels will consist of a very strong ridge over the
eastern half of the U.S. with an embedded 598 dam High over the
Mid-Atlantic States. The embedded High should weaken to about
594 dam and shift over the TN Valley by Wednesday. While we will
have very high heights over our area, the highest will remain
just to our north and northwest. At the surface, High pressure
will be located over the Southeast U.S. through Wednesday,
gradually weakening. Though, there are hints that weak surface
troughing could start to form over our region on Wednesday. This
pattern will usher plenty of moisture into our region. But this
won`t equate to much convection because the aforementioned
ridge and High will limit the convective potential. Models keep
Monday fairly dry, with at most a lone weak shower along the sea
breeze. Tuesday, the models hint at maybe isolated weak
convection along the afternoon sea breeze. Wednesday, should be
a repeat of Tuesday. Overnights should be dry. But the main
story will be the heat. The combination of heights and 850 mb
temperatures will yield above normal temperatures. Highs will
easily climb into the 90s each day, except cooler at the beaches
due to the afternoon sea breeze. Tuesday appears to be the
hottest day in the short term with some inland highs hitting the
upper 90s and making a run for the 100 degree mark. Heat
indices will also climb well into the 100s each day. As of right
now, heat indices hit Heat Advisory criteria (108 degrees) on
Tuesday. But we`re concerned the inland dew points will lower in
the afternoon due to the westerly winds more than the models
are showing, which would cause heat indices to be a few degrees
lower. This will continue to be monitored. Also, low
temperatures will remain very mild and only fall into the low to
mid 70s.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
The strong mid-level ridge initially in place over our region
should weaken by the end of the week. Likewise, the surface High
will shift away from our area and be replaced by surface
troughing. This will cause a gradual increase in diurnal
convection. Temperatures will remain above normal into the
weekend.

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
VFR conditions are expected at CHS/JZI/SAV terminals through 06Z
Tuesday. However, shallow ground fog could develop near the
terminals just before daybreak Monday, especially at KSAV, but
no meaningful reductions in vsbys are expected.

Extended Aviation Outlook: Mainly VFR. There could be brief
flight restrictions due to afternoon/evening convection Thursday
and Friday.

&&

.MARINE...
Tonight: Winds/seas will remain well below Small Craft Advisory
criteria across local waters as Atlantic high pressure continues
to dominate the region through the night. In general, southerly
winds will average around 10 kt or less with seas generally
ranging between 1-2 ft.

Monday through Thursday: High pressure will remain across the
Southeast U.S. the first half of this week, then shift into the
Atlantic for the second half of the week. Surface troughing
should form over our region the second half of this week. But a
typical summertime wind pattern will be in place. 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 it`s passage). Each
night, winds will veer and increase as the nocturnal jet sets
up, especially closer to the coast. Seas will generally be 2 ft.

&&

.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...
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...