Port Royal, South Carolina 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

327
FXUS62 KCHS 211156
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
656 AM EST Thu Nov 21 2024

.SYNOPSIS...
Canadian high pressure will build across the area today and
will remain the primary feature through early next week. A cold
front could approach the area towards the middle of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Today: Surface analysis shows an area of low pressure situated
across the Great Lakes region, with cool dry air building in
across the forecast area. Winds will be in a bit of a lull for
much of the morning, before increasing and becoming gusty this
afternoon ahead of a reinforcing cold front approaching from the
northwest. Frequent gusts into the 20-25 mph range are expected
this afternoon. Today will be a much cooler day, with
temperatures approximately 15 degrees colder than they were
yesterday. Look for highs in the low 60s, though some interior
locations might not get out of the upper 50s.

Tonight: W winds will diminish to 5 to 10 kt. Lows will dip
into the mid to upper 30s inland and lot to mid 40s along the
coast. We expect enough overnight wind to prevent frost
development.

Lake Winds: Winds across Lake Moultrie are past their peak for
the morning, and will likely be diminished a bit through the
morning with speeds around 15 knots. Then this afternoon and
this evening we will see another surge as a reinforcing cold
front approaches and passes through. Another round of sustained
winds in the 15-25 knot range with frequent gusts up to around
30 knots can be expected. Therefore we have opted to keep the
Lake Wind Advisory going even through the lull, and it remains
in effect until 11 pm.

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY/...
Deep mid level low will meander over the Northeast on Friday,
before exiting on Saturday. The pattern will then flatten and be
replaced by weak ridging by the end of the weekend. At the
surface, low pressure will finally exit allowing high pressure
to continue to build over the local area. Gusty winds are
expected on Friday, then the pressure gradient eases through the
weekend. Gusts over Lake Moultrie could approach Lake Wind
Advisory criteria Friday into Friday night, but at this point
remains just shy.

Otherwise, expect full sunshine with moderating temperatures.
It will be coolest on Friday when highs top out in the mid to
upper 50s (~10 degrees below climo). By Sunday, temperatures
will recover to the upper 60s. Lows will be chilly, falling
solidly into the 30s inland of the coast. Attention then turns
to the potential for frost over far interior areas. For Friday
night/Saturday morning, while temps are supportive, winds could
stay too elevated for widespread frost development. Certainly
not out of the question to see patchy frost in more sheltered
locations. For Saturday night/Sunday morning, we did go on the
cooler side of guidance with ideal radiational cooling
conditions in place. As winds are expected to go calm, this
could lead to a higher threat for frost. Will continue to
monitor trends.

&&

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
Surface high pressure will continue to extend into the area
early next week, although a cold front could approach during the
latter half of the period. Still some uncertainties in the
evolution of that feature, whether it actually passes through or
stalls, so changes to the forecast are likely. At this point,
no rain is in the forecast. Temperatures will be above climo for
Monday and Tuesday then possibly cooler for Wednesday if fropa
occurs.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
VFR conditions will prevail at KCHS, KJZI, and KSAV through 12z
Friday. Winds become gusty again this afternoon with frequent
gusts into the 20-25 knot range expected.

Extended Aviation Outlook: VFR. Gusty west winds are expected
Friday.

&&

.MARINE...
Today through tonight: The peak of the morning winds has passed
and we have let the Gale Warning for the outer Georgia waters
expire. Winds across all the waters could actually drop below
Small Craft Advisory thresholds through midday, before ramping
back up this afternoon through the early morning hours as a
reinforcing cold front passes through. Expect west-northwest
winds 20-25 knots with frequent gusts to around 30 knots through
the overnight.

Friday through Tuesday: Gusty west winds will persist over the
coastal waters Friday into Friday night, maintaining the ongoing
Small Craft Advisories. For the Charleston Harbor, gusts should
fall below 25 kt Friday evening so the Advisory is scheduled to
come down at 23z/6 PM. Conditions will improve on Saturday,
with winds and seas remaining below advisory levels through
Tuesday. Winds eventually turn southwest with speeds generally
15 knots or less and seas 1-3 ft.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...Lake Wind Advisory until 11 PM EST this evening for SCZ045.
MARINE...Small Craft Advisory until 6 PM EST Friday for AMZ330.
     Small Craft Advisory until 7 AM EST Saturday for AMZ350-352-
     354.
     Small Craft Advisory until 10 AM EST Saturday for AMZ374.

&&

$$

NEAR TERM...BSH/Dennis
SHORT TERM...ETM
LONG TERM...ETM
AVIATION...BSH/ETM
MARINE...Dennis/ETM