386
FXUS62 KCHS 162250
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
650 PM EDT Mon Sep 16 2024

.SYNOPSIS...
Low pressure will shift inland across the Carolinas and weaken
tonight into mid week. High pressure should develop inland late
week into the weekend.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
Tonight: Low pressure centered north of the local area off the South
Carolina Coast will move slowly northwest and inland across the
Carolinas, gaining latitude and shifting further away from the
region overnight. South of this feature, sfc winds should gradually
back to the north-northwest this evening, then west-northwest by
midnight, slowly diminishing as the low tracks further away from the
region. A few light showers could drift into extreme northwest
locations of Berkeley County this evening, before drier air
(depicted on latest water vapor imagery) overtakes lingering low-lvl
moisture. Expect dry conditions to prevail across all areas by
midnight. Latest vis sat imagery continues to indicate broken to
overcast low clouds locally early this evening, but expect some of
these clouds to erode with drier air shifting into the area through
the night. Given breaks in clouds and sfc winds weakening overnight,
temps should dip into the mid 60s inland to upper 60s near the
coast. Some lower 60 temps are not out of the question across
Southeast Georgia well inland should clouds erode more quickly
overnight.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
The remnant low of PTC8 should be somewhere over the Carolinas at
the start of the period. The surface low will continue to weaken
with time. An associated trough axis/weak boundary should transition
back towards the coast and possibly offshore on Thursday. Tuesday
should actually be rain-free over the local area, then isolated to
perhaps scattered showers will return for Wednesday and Thursday
with deeper moisture and upper trough moving back overhead. High
temperatures a touch below normal on Tuesday will warm to the mid to
even upper 80s for mid week. Lows will range from the upper 60s
inland to low/mid 70s at the immediate coast.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
Mid level trough axis initially stretched down the east coast should
push a bit east over the weekend as a ridge centered over southern
Texas nudges into the region. Still some spread between models
during the latter half of the weekend with regards to if a mid level
low forms off the coast and how far offshore that would be. At the
surface, high pressure is expected to build south into the Carolinas
and Georgia. This pattern generally favors lower rain chances, so
PoPs are no higher than 20% and only located closer to the coast.
Temperatures will lean on the cooler side of normal through the
period.

&&

.AVIATION /22Z MONDAY THROUGH SATURDAY/...
Guidance indicating the potential for MVFR CIGS to hang on through
the evening at KCHS and KJZI, possibly rising to VFR after midnight.
Have kept MVFR at KCHS/KJZI through about 06/07Z, then trended into
prevailing VFR through 18Z Tuesday. At KSAV, periodic MVFR CIGS are
expected through about sunset, followed by prevailing VFR through
18Z Tuesday.

Extended Aviation Outlook: Low chance for brief flight restrictions
in showers and thunderstorms Wednesday and Thursday.

&&

.MARINE...
Tonight: Conditions will gradually improve as low pressure centered
north of the area off the Carolina Coast moves slowly northwest and
further away from the region overnight. Small Craft Advisories will
remain in effect across local waters outside the CHS Harbor this
evening, but trends suggest northwest/west winds and seas to
drop below advisory criteria across nearshore waters south of
Edisto, SC during the next few hours, then potentially across
Charleston County waters around midnight. 6 ft seas will likely
linger across offshore Georgia waters through the night, so a
Small Craft Advisory is expected to continue into Tuesday.

Tuesday through Saturday: Fairly benign marine conditions are
expected through at least Friday with wind speeds generally less
than 15 knots. Seas will subside on Tuesday, settling in 2-4 foot
range thereafter. High pressure should build south into the
Carolinas and Georgia late week into the weekend. Winds will turn
out of the northeast and could see some increase in speeds with the
pressure gradient tightening.

Rip Currents: Lingering swell of around 3 ft every 10 seconds and
astronomical influences from the full moon and perigee will maintain
a High Risk of rip currents for all beaches through Tuesday. It
is worth noting that local calculations for Georgia beaches were
borderline moderate-high but opted to maintain the High for now.

&&

.TIDES/COASTAL FLOODING...
This Evening: The latest departures are in the 0.4-0.5 range at
the Charleston tide gauge. With these departures expected to
hold during the next few hours, tide levels could reach around
7.2 MLLW. A Coastal Flood Advisory has therefore been issued for
Charleston and Coastal Colleton Counties until 9 PM.

Tides are expected to remain below Coastal Flood Advisory Levels
for the remainder of our coastline from Beaufort County, SC
southward to McIntosh County, GA.

As we continue into mid to late week, the risk for at least
minor flooding will continue for Charleston and Coastal Colleton
Counties due to high astronomical tides with the full moon on
September 17th.

Beaufort County, SC, south to McIntosh County, GA: Waters levels
could be close to minor flood levels later this week as onshore
winds return.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...High Risk for Rip Currents through Tuesday evening for GAZ117-119-
     139-141.
SC...High Risk for Rip Currents through Tuesday evening for SCZ048>051.
     Coastal Flood Advisory until 9 PM EDT this evening for SCZ049-
     050.
MARINE...Small Craft Advisory until midnight EDT tonight for AMZ350-352-
     354.
     Small Craft Advisory until 1 PM EDT Tuesday for AMZ374.

&&

$$

NEAR TERM...DPB
SHORT TERM...ETM
LONG TERM...ETM
AVIATION...RFM
MARINE...DPB/ETM