951
FXUS62 KCHS 092129
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
429 PM EST Sat Nov 9 2024

.SYNOPSIS...
High pressure will remain ridged across the region Sunday into
Monday, followed by a cold front Monday night into early
Tuesday. High pressure will return for the middle of next week.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
This afternoon, visible satellite showed a band of clouds associated
with the cold front near the FL/GA line, extending well east across
the Atlantic Ocean. Stable ENE winds will remain across the forecast
area north of the cold front into early this evening.

A strong sfc ridge will remain across the forecast area through
tonight. LLVL winds are forecast to turn from the SE and increase to
around 30 kts. These winds should develop a band of isentropic lift
across SE GA into the southern most SC counties. NAM12 indicates
that 300-310K isentropic lift will begin by 3Z and increasing
through 12Z Sunday. The combination of weak lift and PW around 1.75"
should support rounds of sprinkles or isolated showers across the
Savannah River Valley to scattered showers across SE GA. Some
locations along the GA coast could receive around a quarter of an
inch of rain tonight. Low temperatures are forecast range from
around 60 degrees inland to the mid to upper 60s along the
coast.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY NIGHT/...
Sunday: Surface high pressure will be centered off the coast of
NJ in the morning. The surface high pressure will continue to
move east during the day, with a coastal trough pushing inland
along with a warm front. As this occurs, showers will likely
move inland across GA in the morning hours and then translate to
SC by Sunday night. This type of general progression of showers
is very typical with a retreating high pressure and with PWATs
~1.80", have expanded the chance PoPs. Expect high temperatures
mostly in the 70s for most of the area (high 70s at the coast
and low 70s inland) with lows ranging from around 60 degrees far
inland to the upper 60s near the beaches.

Monday: Early Monday morning, a weak low amplitude short wave
will cross the region, with mid-level dry air also slowly
working into the area. This forcing is weak to moderate (30 to
60 m height falls) which will likely keep the light showers
going into Monday morning. By the afternoon, a slight chance of
a shower will still exist as PWATs remain around 1.40" with
saturation confined to the 700/ 900 mb layer. This will likely
translate to any showers that do form to remain rather low
topped. Even though cloud cover will likely be widespread
Monday, the entire region will be in the WAA wing of the
approaching cold front with 850 mb temperatures approaching 15
degrees C. This will fuel highs in the lower 80s for most of the
area. As the mid-level wave exits the region, a prefrontal
trough will develop with winds turning from the northwest.

Tuesday: A potent upper level low will move east across the
Hudson Bay with surface high pressure rapidly following. When
this occurs, frontal zones typically fracture across the
Appalachians with an inverted v frontal zone setting up with the
cold front across NC racing south and southwest. The front then
typically extends west towards Columbia, SC and then southwest
to south central GA. This means the frontal zone will take its
time to completely clear the area, and likely not clear SC and
GA until Tuesday night. No precipitation is expected with this
frontal passage as very little surface convergence exists and
PWATs continue to fall below 1.00". Expect high temperatures
mostly in the mid to upper 70s.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
High pressure is forecast to prevail through Wednesday night behind
a cold front that crossed the region on Tuesday. Temperatures are
generally expected to be near normal.

Another cold front will then approach the region late Thursday, with
more high pressure forecast on Friday. No precipitation is expected
with temperatures near normal.

&&

.AVIATION /22Z SATURDAY THROUGH THURSDAY/...
Prior to the 18Z TAFs, visible satellite indicated the back edge
of MVFR ceilings was over KSAV. Based on satellite trends, these
clouds should push south of the KSAV terminal by 1830Z. The rest
of the day should feature VFR conditions with ENE winds, gusty
at KJZI. This evening, a belt of isentropic lift and moisture
should yield an area of MVFR ceilings along and south of the
Savannah River, including KSAV. The KSAV TAF will feature MVFR
ceilings developing by 2Z. Cloud bases are forecast to lower and
the number of showers gradually increases. Beginning daybreak
Sunday, the KSAV TAF will feature vicinity showers along with
persisting MVFR ceilings, remaining through the rest of the 18Z
TAFs. For KCHS and KJZI, conditions will remain VFR with gradual
lowering cloud bases.

Extended Aviation Outlook: Prevailing VFR. Some brief flight
restrictions will be possible Sunday night into Monday from passing
showers.

&&

.MARINE...
Tonight: The marine zones will remain between a cold front to the
south and high pressure centered over New England. The pinched
pressure gradient should support northeast winds of 20 to 25 kts
with gusts around 30 kts through this evening. Some spots may
approach gales at times this evening. The winds will gradually
weaken late tonight as the pressure gradient decreases. Seas are
forecast to build through most of tonight, peaking between 5-8 ft
during the pre-dawn hours. Small Craft Advisories will remain in
effect outside the CHS Harbor through tonight. The CHS Harbor Small
Craft Advisory is scheduled to end at 10 PM.

Sunday: A stationary coastal front will be just along the SC/ GA
coast with surface high pressure centered over NJ. This surface high
will quickly move east off the Mid-Atlantic coast with the
stationary coastal front quickly starting to buckle. An inverted
coastal trough will then move onshore with a warm front sweeping
inland. Winds over the waters will initially be out of the east and
then quickly veering around from the southeast and slowly decreasing
in speed.  As the inverted trough moves inland, scattered showers
will also sweep across the waters from southwest to northeast. The
Small Craft Advisories within 20 nm should come to an end by the
evening. But the Small Craft Advisory for the GA waters beyond 20 nm
should persist into the overnight because seas will take longer to
subside.

Monday: A cold front will approach the area from the west with a pre-
frontal trough forming near coast Monday afternoon. Winds will be
below Small Craft Advisory criteria with seas also falling below
criteria or 3 to 5 ft.

Tuesday: The prefrontal trough will clear the coastline Tuesday
morning with the surface cold front rapidly approaching from the
west. A mid-level wave, responsible for the pre-frontal, will clear
the coast with the surface cold front clearing the NC water. As this
occurs, a fractured frontal pattern will develop with the cold front
picking up speed on the northern edge (NC waters), while the frontal
zone will lag over GA. This will allow the front to clear the SC
waters first (Tuesday morning), with the GA waters having the
front clear the zones Tuesday afternoon. Winds will be from the
north and then quickly veer from the northeast and increase
speed with sustained values 15 to 20 kt and gusts up to 25 kt.
As of current, winds look to be just shy of Small Craft Advisory
criteria, but it will be close.

Wednesday: Cold air advection will persist through the early morning
hours of Wednesday morning with wind gusts reaching Small Craft
Advisory Criteria. Seas will also be increasing 5 to 7 ft.

Thursday: Surface high pressure will move overhead with winds out of
the north 10 to 15 kt with gusts 15 to 20 kt. Seas will also be
slowly falling 3 to 5 ft.

&&

.CLIMATE...
This November has been off to an extremely warm start across the
coastal South Carolina and Georgia. The fist eight (8) days of
November are the warmest on record for Charleston, SC. It is tied
for the warmest on record for Savannah, GA

Charleston, SC (November 1st - 8th)
   Year     Average Temperature (degrees F)
   2024            72.7
   2003            71.8
   1961            71.6
* Period of Record (1937 - 2024)


Savannah, GA (November 1st - 8th)
   Year     Average Temperature (degrees F)
   2024            73.4
   2003            73.4
   2015            73.0
* Period of Record (1874 - 2024)


&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...Small Craft Advisory until 10 PM EST this evening for AMZ330.
     Small Craft Advisory until 4 PM EST Sunday for AMZ350-352.
     Small Craft Advisory until 7 PM EST Sunday for AMZ354.
     Small Craft Advisory until 4 PM EST Monday for AMZ374.

&&

$$

NEAR TERM...NED
SHORT TERM...Haines
LONG TERM...Haines
AVIATION...Haines/NED
MARINE...Haines/NED