Hilton Head Island, South Carolina 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

746
FXUS62 KCHS 310531
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
131 AM EDT Mon Mar 31 2025

.SYNOPSIS...
Rain and thunderstorm chances continue again Monday ahead of an
approaching cold front. The front could linger nearby mid-week,
before stronger high pressure prevails late this week.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
The back edge of some lingering showers associated with a subtle
coastal trough and short wave aloft will pull away, followed by
low stratus and patchy fog due to the wet grounds and
considerable moisture trapped beneath the inversion. Low level
winds might be too strong for any significant fog concerns, and
as such we have no worse than the qualifier of "patchy" fog.
Given the cloud cover and elevated dew points, it won`t be as
cool as recent nights. Lows will generally be in the upper 50s
and lower 60s, with a few places only dipping into the mid 60s.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY/...
The most active period of the forecast will be Monday as a mid-
level trough, initially centered near the Mississippi River
Valley, swings eastward towards the East Coast. At the surface
an associated cold front will approach the local forecast area
from the west. Ahead of the cold front a line of showers and
thunderstorms is forecast to push through the region, bringing
the threat for severe weather. More details on that below. With
southwesterly flow aloft solid WAA will impact the region,
leading to another above normal day in regards to high
temperatures. Highs are forecast to reach into the low to mid
80s across the region. Additionally, dew points are expected to
surge into the upper 60s, providing a moist environment for
shower and tstorm formation. The timing for the line of showers
and storms has not changed significantly from the previous
forecast. The line will likely move into the western parts of
the forecast area in the mid-afternoon, pushing eastward and
reaching the coast by early evening.

Regarding the severe weather potential on Monday: The Storm
Prediction Center continues to highlight the forecast area in an
Enhanced Risk (level 3 out of 5). The main threat is severe damaging
wind gusts, however hail and isolated tornadoes cannot be ruled out.
CAMs indicate that there will be between 1000-1500 J/kg of ML CAPE
Monday afternoon, which combined with the forecast arrival time of
mid-afternoon, the showers and thunderstorms should be able to
utilize the instability. Additionally, shear values range between 30-
40 knots and forecast soundings show DCAPE values upwards of 800
J/kg. Therefore, strong, damaging wind gusts are the main hazard
with the line of showers and thunderstorms. While large hail and
tornadoes cannot be ruled out, 0-3km SRH values of >100 m2/s2 and
low-level lapse rates between 5-6 C/km indicate that the risk for
large hail and tornadoes is low. Generally rainfall amounts are
forecast to be between 0.5 and 1 inch, however higher rainfall
amounts are certainly possible with thunderstorms.

The cold front will push off the coastline overnight Monday, likely
stalling in the vicinity of the local offshore waters. Little change
in airmass is expected with overnight temperatures in the upper 50s
to low 60s. Temperatures on Tuesday and Wednesday will remain above
normal, reaching into the low to mid 80s each day. With the front
lingering in the vicinity, moisture will remain elevated across the
region and isolated showers will be possible overnight Tuesday into
Wednesday afternoon.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
The remainder of the week will feature high pressure both aloft and
at the surface, yielding a dry and warm forecast. The main forecast
highlight through the week will be the warm temperatures. Highs on
Thursday and Friday could approach 90 degrees in some locations,
with mid to upper 80s elsewhere. These values could challenge the
record high temperatures at our three climate sites Thursday through
Saturday. Overnight lows will similarly be above normal, only
dipping into the mid 60s, possibly challenging some record high
minimum temperatures as well.

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
KCHS/KJZI/KSAV: Given the wet grounds and the build down of low
stratus, LIFR conditions have already formed at KSAV, and will
develop at the other airfields around 09Z. Ceilings will be down
at least in the airfield minimum range until about 14-15Z. As
mixing heights climb, a return to MVFR ceilings will then
occur, before VFR returns by 17-18Z. A squall line with its
associated convection will then sweep through from about 21Z to
01Z, resulting in at least MVFR conditions and briefly strong
and gusty winds peaking at least around 30 kt. VFR returns
thereafter, with some chance for a few more showers later on as
the cold front moves through.

Extended Aviation Outlook: Low ceilings are possible again on
Wednesday along with some isolated showers.

&&

.MARINE...
Overnight: The Atlantic high will shift farther east as a cold
front approaches the region well after daybreak Monday. Winds
will turn more southerly, but remain well below Small Craft
Advisory levels through the night (10-15 kt). Seas will
generally range between 3-5 ft. The main concern will be the
possibility for sea fog to develop late, within a warm and
moisture airmass atop somewhat cooler waters. At this time,
patchy fog remains in the forecast across nearshore waters,
including the Charleston Harbor late.

Tuesday through Thursday: The aforementioned cold front will linger
in the vicinity of the marine waters through mid-week, with high
pressure building in thereafter. Generally quiet marine conditions
are forecast through the end of the week, with winds around 10 knots
and seas averaging 3 to 4 ft.

&&

.EQUIPMENT...
The KCLX radar remains offline for dome maintenance through
April 1, 2025. Radar data will not be available during this
time. Users are urged to use adjacent WSR-88D sites which also
cover much of Southeast South Carolina, Southeast Georgia and
the adjacent coastal waters. These include:

KCAE - Columbia, SC
KLTX - Wilmington, NC
KJAX - Jacksonville, FL
KVAX - Moody AFB, GA
KJGX - Robbins AFB, GA

&&

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

&&

$$

NEAR TERM...
SHORT TERM...CPM
LONG TERM...CPM
AVIATION...
MARINE...