Port Royal, South Carolina 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

879
FXUS62 KCHS 310223
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
1023 PM EDT Sun Mar 30 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 MONDAY MORNING/...
Late this evening, a cluster of showers with embedded
thunderstorms was tracking north of the GA coast and adjacent
waters. This activity should generally remain over the marine
areas through late tonight, gradually weakening. The forecast
update will feature lower PoPs and less QPF over land.

After Midnight: The main concern for the night will continue to
be the possibility for fog across the area. As the convection
comes to an end, low stratus/stratocumulus will develop, as a
warm front lifts north-northeast through the area. This along
with the wet grounds will lead to at least some fog formation.
Latest trends continue to indicate at least patchy fog developing
across the entire area. Dense fog is possible late, but 10-15 kt
geostrophic winds at 1000 mb suggest some limitation to overall
coverage and perhaps more of a low-stratus scenario late. Temps
will remain mild through the night, with lows only dipping into
the low-mid 60s.

&&

.SHORT TERM /6 AM MONDAY 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 /03Z MONDAY THROUGH FRIDAY/...
Prior to the 0Z TAFs, radar composite indicated a large patch of
light to moderate rain between KCHS/KJZI and KSAV, drifting to
the northeast. Based on upstream observations and radar trends,
it appears that as rainfall rates increase slightly later this
evening, MVFR vis and ceilings may develop over KCHS/KJZI,
highlighted with a TEMPO from 0-3Z. After 3Z, forecast soundings
show a significant inversion developing around 2 kft. Steady SE
winds below the inversion should increase moisture and stratus
should develop, then build down through the rest of the night.
The TAFs will indicate IFR ceilings developing around 3Z, then
LIFR during the pre-dawn hours. MOS indicates that LIFR stratus
may linger through much of Monday morning. If this occurs, then
the potential for severe weather will decrease with the arrival
of afternoon and evening thunderstorms. TAFs will indicate that
the stratus will mix out during the early afternoon. Each TAF
will feature a TEMPO from 21-24Z for thunderstorms, at least
MVFR visibility, and gusty WSW winds.

Extended Aviation Outlook: Reductions in visibility and ceiling are
likely Monday afternoon int the evening as a line of showers and
thunderstorms pushes through the region. Low ceilings are possible
again on Wednesday along with some isolated showers.

&&

.MARINE...
This Afternoon into Early Evening: High pressure centered east of
Bermuda will extend across the immediate waters, with the associated
ridge axis just to the north early on sagging south late day. The
pressure gradient remains rather weak across local waters, but
sufficient to generate SE winds up to 10-15 kt. Seas will be a mix
of swells and wind driven wave, resulting in significant wave
heights of 3-5 ft across local waters, largest across outer Georgia
waters. Mariners could experience some thunderstorms late afternoon
into early evening, mainly south of Edisto. Instability and shear
remain on the lower side, limiting the risk to near zero for strong
and/or severe thunderstorms. Keep in mind though that lightning
strikes will occur.

After Midnight: The Atlantic high will shift farther east as a cold
front approaches the region well after daybreak Sunday. 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...DPB/NED
SHORT TERM...CPM
LONG TERM...CPM
AVIATION...NED
MARINE...CPM/DPB