Port Royal, South Carolina 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

161
FXUS62 KCHS 260611
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
211 AM EDT Tue May 26 2026

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

&&

.KEY MESSAGES...
- 1) Periods of showers and thunderstorms this week through the
  weekend could bring locally heavy rainfall. The threat for
  organized severe weather is low at this time.

&&

.DISCUSSION...
KEY MESSAGE 1: Periods of showers and thunderstorms this week
through the weekend could bring locally heavy rainfall. The
threat for organized severe weather is low at this time.

Satellite water vapor indicates that a some drier air is starting to
push onshore along the coast of GA/SC. Near-term guidance indicates
that H5 heights associated with a 593 dm ridge centered over the
western Atlantic will build over the coastal counties. In fact,
recent runs of the HRRR forecast soundings indicate a significant
subsidence inversion centered around H7 near the coast. Further
inland, PW values should remain a bit greater, generally between 1.8-
1.9". In addition, the H7 inversion appears a degree or two weaker
than near the coast. Once the sea breeze develops and pushes inland,
showers and thunderstorms should develop across inland GA and SC.
Some of these storms may develop heavy downpours, however, potential
for excessive rainfall appears less than the past several days.
Given a bit less coverage of convection, temperatures may range a
degree or two warmer than recent days. High temperatures are
forecast to range around 90 along the coast to the upper 80s inland.
In the wake of the sea breeze, deeper mixing may yield a period of
gusts between 20-25 mph this afternoon.

As an upper level trough begins to move out of the northeast on
Wednesday, the ridge of high pressure off to our east starts to move
off to the south. While that occurs throughout the day, the surface
high pressure similarly shifts southwards. Before it moves too
far away, the continuation of similar meteorological conditions
will result in warm and moist conditions, with chances for
showers and thunderstorms continuing. The most widespread
coverage is expected during the afternoon and evening hours
after the sea breeze initiated the thunderstorms, and given
PWATs remaining near 2 inches, locally heavy rainfall will
remain possible. Temperatures remain warm, in the mid 80s to
lower 90s.

Moving into Thursday, the aforementioned upper level trough has an
accompanied surface cold front that moves towards the area from the
north. The front will bring additional chances for showers and
thunderstorms, mostly starting in the afternoon, with temperatures
remaining warmer in the upper 80s to lower/mid.

Rain chances will increase Friday and into the weekend as the front
meanders/stalls in the vicinity, bringing a more widespread pattern
of showers and thunderstorms. Models continue to hint that a weak
surface low pressure (or two) may spawn along the front, though
ensemble clustering analysis shows rather poor agreement, lowering
confidence a smidge. Moisture convergence along the front and/or
surface lows will increase PWATS to around 2.0 - 2.2 inches Friday
and into the weekend. Several rounds of rainfall which could be
heavy at times, may lead to localized minor flooding, especially in
areas that see repeated storms. Current forecast guidance suggests
widespread rainfall totals through the weekend remain around 2 to 4
inches. The NBM continues to show a 20-35% probability of 3 inches
of rain or greater falling over a 72-hour period between Friday and
Monday morning, with the highest chances located along the coast.
While confidence is increasing in a wetter pattern later this week
and weekend, details on exact rainfall totals and where the heaviest
rain sets up will likely change over the coming days.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
Prior to the 6Z TAFs, observations indicate patches of MVFR ceilings
across SE GA/SC, impacting the KSAV and KJZI terminals. Rounds of
MVFR ceilings are possible through the rest of the night,
highlighted in the TAFs will either in the initial FM groups for
KSAV and KJZI or a TEMPO from 6-10Z at KCHS. The terminals will
remain under slightly stronger mid-level ridging today. Convection
should favor areas west of I-95. KSAV will see the greatest chance
for showers around dawn and again late this morning with the onset
of the sea breeze, highlighted with VCSH. Once the sea breeze
passes, south winds should strengthen to 10 to 15kts with gusts into
the low 20 kts. South winds are forecast to settle near 10 kts by
23Z.

Extended Aviation Outlook: TEMPO flight restrictions possible with
showers and thunderstorms at CHS/JZI/SAV terminals during the
afternoon hours into the later half of the week. In addition, patchy
overnight fog and/or stratus cannot be ruled out after recent rains.

&&

.MARINE...
Today and tonight: The marine zones will remain under the influence
of broad high pressure through the period. South winds should remain
between 10 to 15 kts with some gusts into the low 20s. Wave heights
will favor values between 4-5 ft.

Wednesday through Saturday: Conditions are forecast to remain below
Small Craft Advisory criteria into the beginning of the weekend,
with daily chances for showers and thunderstorms. Thursday and
Friday will see a stalled front near the area, keeping winds on the
weaker side. There is potential for a weak surface low pressure (or
two) to form along the stalled front, which would bring an increase
in wind speeds along with wave heights to near/above Small Craft
Criteria on Sat/Sun, with confidence low/moderate at this time.

Rip Currents: An elevated rip current risk will remain through the
week with a modest easterly swell around 3 to 4 feet every 7 seconds
and sea breeze influences. A moderate risk of rip currents is in
place for all area beaches through at least Wednesday.

&&

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

&&

$$

APT/NED