Port Royal, South Carolina 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

270
FXUS62 KCHS 251111
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
711 AM EDT Sat Apr 25 2026

.WHAT HAS CHANGED...
All sections have been updated.

&&

.KEY MESSAGES...
- 1) A cold front will push across southeast Georgia and the
  South Carolina Lowcountry tonight into Sunday, bringing
  increased rain chances.

&&

.DISCUSSION...
KEY MESSAGE 1: A cold front will push across southeast Georgia
and the South Carolina Lowcountry tonight into Sunday, bringing
increased rain chances.

Through Saturday night, the upper pattern will feature mostly
zonal flow will some embedded shortwave energy. At the surface,
a cold front situated upstream of the forecast area will start
to draw closer from the west, especially during the overnight.
We will see moisture profiles improve through the period, with
precipitable water increasing into the 1.25-1.50" range and
likely peaking during the evening and early morning hours. The
combination of some shortwave energy aloft and increasing
moisture ahead of the approaching front should result in more
shower and thunderstorm coverage than we have seen in quite some
time. Hi-res model guidance would suggest that convection will
start in the afternoon as some combination of upstream
development moving in from the west ahead of the front, along
with development along the sea breeze as well. Conditions
shouldn`t support robust coverage, with mainly isolated to
scattered activity expected. Model soundings do not support much
instability, supported by low probabilities noted in the HREF
for CAPE values in excess of 500 J/kg. Therefore, the severe
threat is virtually zero. Through the evening and overnight, we
could continue to see isolated to scattered showers (and a
thunderstorm or two) as the area continues to sit within the
moisture feed ahead of the front. Therefore, rain chances
continue through the night. While locations directly impacted by
passing showers and storms could see rainfall amounts of a
quarter of an inch or more, overall rainfall will be quite
variable with most areas remaining dry. Expect another warm day
with highs reaching the upper 80s for much of the area, running
about 8-10 degrees above normal.

By Sunday morning, the front will extend across the Carolina
Midlands and into central Georgia, gradually pushing toward the
coast through the day. By this point, the deeper moisture will
be pushing offshore with isolated, or at best, scattered showers
expected ahead of the front prior to its offshore passage in
the evening. Although instability has trended downward, SBCAPE
values are still expected to reach around 1000 J/kg Sunday
afternoon, which could support a few isolated thunderstorms. It
wont be until Sunday night, when dry high pressure builds in
from the north, that precipitation chances will fully diminish
and skies begin to clear.

While any rainfall will be beneficial, this system is not
expected to provide significant relief from ongoing drought
conditions. Recent model trends indicate slightly lower rainfall
totals, with most areas receiving between 0.10 and 0.25 inches.
A few inland locations could see up to around 0.50 inches,
particularly where the front slows and convection becomes more
concentrated. However, given the isolated to scattered nature of
convection, some areas could receive no measurable rainfall.

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
The 12z TAF period begins with VFR conditions at KCHS, KJZI,
and KSAV. Overall, VFR conditions should persist through the TAF
period, though there is some potential for showers and
thunderstorms near the terminals late this afternoon, through
the evening, and even into the early morning hours. The best
chance for showers and storms appears to come first at KSAV
along the sea breeze late this afternoon. Confidence is still
low, especially in the thunder potential, so we have only
advertised VCSH starting at 22z. The shower potential will
likely arrive later at KCHS and KJZI, more into the evening and
the latter portion of the TAF period. Overall coverage is only
expected to be isolated to scattered so the potential for direct
impacts is still relatively low. Conditions do not look very
unstable, so the potential for thunder isn`t considered to be
particularly high at this point. Shower activity should
dissipate by the early morning hours.

Extended Aviation Outlook: Showers and isolated thunderstorms
associated with a cold front could bring reduced vsbys/cigs
Sunday and possibly again midweek.

&&

.MARINE...
Through Saturday night: An inland cold front will begin to
approach from the west though the subtropical high will remain
the primary driver of the the flow pattern across the local
waters. Southwest flow in the morning will turn more southerly
in the afternoon with the onset of the sea breeze. We should
then see modestly higher south to southwest flow through the
overnight as the front draws closer. Speeds will mostly top out
around 10-15 knots, except up to 15-20 knots along the land/sea
interface and the Charleston Harbor in the afternoon and early
evening. Seas are expected to average 2-3 feet through the
period.

A cold front will push offshore Sunday. High pressure building
in from the north Sunday night will bring a brief northeast
surge of 15-20 kt winds into early Monday. Conditions could
approach Small Craft Advisory levels, with gusts up to 25 kt and
seas nearing 6 ft. Winds and seas diminish thereafter as the
pressure gradient relaxes.

&&

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

&&

$$

BRS/BSH