946
FXUS62 KCHS 040753
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
353 AM EDT Sun Oct 4 2026

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

&&

.KEY MESSAGES...
- 1) Unsettled weather with a risk for minor/flash flooding
  today into Monday.

- 2) Cooler temperatures along with breezy to windy conditions are
  expected into the middle of the week.

- 3) Coastal flooding and significant coastal hazards are
  expected this week.


&&

.DISCUSSION...
KEY MESSAGE 1: Unsettled weather with a risk for minor/flash
flooding today into Monday.

Today and Monday: Weak high pressure across the western Atlantic
will shift further offshore early week as a mid-upper lvl trough
advances from the Great Lakes region to the Northeast United States.
The large-scale trough will help force a cold front south into the
local area today, which should become the main focus of shower and
thunderstorm coverage before weak low pressure begins to take shape
offshore. Expect rain/shower activity to increase in coverage during
morning hours while deep moisture (PWATs 2.25 to 2.5 inches) is
drawn into an area of favorable isentropic lift ahead of the
approaching front. Questions still remain as to how far the cold
front advances south initially today before stalling across the
local area this afternoon into evening hours, but the setup favors
widespread rain/showers across Southeast South Carolina late
morning/afternoon, then across Southeast Georgia later in the day.
Areas that remain south of the front should see the greater chance
for thunderstorms this afternoon, where modest instability is in
place prior to rainfall. A stronger thunderstorm can not be ruled
out if loosely organized activity congeals quickly prior to more
numerous/widespread precip coverage. However, the main issue will
continue to focus on a minor/flash flooding risk for areas that see
brief heavy downpours and/or activity that trains over saturated
grounds along/near the stalling front.

The greatest risk for flooding should start up this afternoon and
likely continue through the night given the nearby stationary front
and deep moisture in place. It will take a secondary reinforcement
of the mid-upper lvl trough advancing toward the Mid-Atlantic and
Northeast United States to nudge the sfc front south and offshore
Monday, prolonging the risk of minor/flash flooding potential
through late morning/mid-day. There could be a fairly significant
gradient in precip coverage/amount as a result Monday, but the
overall trend would suggest north and inland areas to be at less
risk and coastal/southern areas more at risk for flooding issues as
a wedge builds south across the Carolinas while low pressure
develops offshore. Total rainfall amounts during this 48-hr period
remain in the 2-3 inch range for much of the area and the 3-4 inch
range along and south of I-16 in Southeast GA with perhaps greatest
amounts occurring in two waves, first with the nearby stationary
front this afternoon/evening, then again tonight into early Monday
with low pressure passing/developing offshore. Locally higher
rainfall amounts are possible. The latest WPC Excessive Rainfall
Outlook includes the entire area in a Slight Risk today and a
Marginal Risk for Monday.

KEY MESSAGE 2: Cooler temperatures along with breezy to windy
conditions are expected into the middle of the week.

Sunday-Monday: Expect near-normal afternoon highs today in the lower
to mid 80s, though a cold front pushing through on Monday will usher
in some cooler temperatures as a cold air damming (CAD) event takes
shape. Daytime highs will struggle to get out of the mid to upper
70s on Monday given the persistent rainfall, with northeasterly
winds picking up throughout the day though gusts should remain below
20 mph.

Tuesday: Overnight into Tuesday, a strong surface high pressure
moves out of the Great Lakes region and towards the northeast coast,
with a surface low likely developing along the cold front offshore
of GA/FL. This will result in increasingly breezy/windy conditions,
peaking Tuesday afternoon and decreasing slowly into the overnight
hours. Strength of the winds remain largely unchanged, with areas
furthest away from the coast possibly seeing gusts to 30 mph, while
those along the coast will be in the 35 to 45 mph range. This may
necessitate the need for a wind advisory along the coast, with a
Lake Wind advisory possible as well for Lake Marion. In addition,
chances for light rain will persist as weak shortwaves make their
way around the base of the trough, mostly impacting portions of
southeast Georgia, though rainfall amounts look light at under half
an inch. With h925 temps dropping into the 16-18 deg C range, high
temperatures remain in the lower to mid 70s

Wednesday: The surface high pressure weakens slightly as it slides
down the east coast, with the aforementioned surface low remaining
well offshore of GA/FL keeping the surface pressure gradient
elevated across the region before decreasing throughout the
afternoon hours. Areas far from the coast will likely see gusts to
20 mph while those along the coast will be closer to 30 mph during
the morning hours, decreasing into the afternoon and evening hours.
Chances for rainfall look to be rather low as dry low-mid levels
overspread the area. Temperatures on Wednesday are a bit more
uncertain as models tend to underestimate how quickly the CAD
erodes, with the NBM sitting between the 50th and 75th
percentile...so be aware the forecast for Wednesday may trend
cooler.

Thursday-Friday: As weak ridging occurs aloft, surface high pressure
looks to linger across the southeast region with the area of low
pressure well offshore of GA/FL continuing as well. This will result
in breezy daytime conditions with gusts to near 20 mph on both days.

KEY MESSAGE 3: Coastal flooding and significant coastal hazards are
expected this week.

Coastal Flooding: Strong northeast winds associated with a wedge of
high pressure inland and low pressure offshore in combination with
high astronomical tide levels will likely support coastal flooding
issues this week. The pattern suggests a minor/moderate saltwater
inundation setup by mid-week, but even major coastal flooding cannot
be ruled out during the peak of the event given persistent/strong
northeasterly winds and building seas along the Southeast U.S.
Coast. Coastal Flood Watches/Warnings and/or Advisories could be
needed.

Rip Currents/High Surf/Beach Erosion: The setup looks favorable for
strong and dangerous rip currents by Tuesday with gusty northeast
winds expected. In addition, there will be an increased risk for
high surf along the beaches with the latest guidance showing a
potential for 4-6 ft breakers developing in the Southeast SC/GA surf
zone by Tuesday afternoon and lingering in the Southeast GA surf
zone into Wednesday. A High Surf Advisory may eventually be needed
for some beaches. Significant beach erosion is also likely,
particularly around times of high tide. Guidance suggests beach
erosion chances are highest around the Tuesday afternoon high tide.

&&

.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
CHS/JZI: Periods of MVFR conditions are expected early this morning
through 06Z Sunday as rounds of showers impact the terminals in
advance of and nearby an arriving front. TEMPO IFR cigs also remain
possible during showers that directly impact the terminals,
especially if occurring prior to daybreak today. Another round of
IFR conditions is possible as a wedge of high pressure builds across
the area between 00Z-06Z Monday, and should eventually be included
in future TAF issuances.

SAV: Periods of MVFR conditions are expected early this morning
through 06Z Sunday. TEMPO IFR conditions are also possible during
the next few hours, and possibly through daybreak today. In addition
to showers, a few thunderstorms could impact the terminal during
afternoon hours with a risk for producing MVFR or lower conditions.
A PROB30 group for thunderstorms and low-end MVFR conditions has
been introduced between 18-24Z today, but could eventually require
IFR conditions. IFR conditions are also possible as a wedge builds
south into the area overnight, starting between 02-06Z Monday, and
could eventually be included in future TAF issuances.

Extended Aviation Outlook: Flight restrictions are possible with
showers and thunderstorms on Monday. Gusty winds and MVFR (or lower)
stratus are likely on Tuesday, with breezy winds continuing on
Wednesday.

&&

.MARINE...
Today and Tonight: Wind/seas are expected to remain well below Small
Craft Advisory levels as Atlantic high pressure continues to shift
further offshore in an advance of a cold front entering the area
from the north and stalling nearby this afternoon into the evening.
The greatest impact across local waters should occur with gusty
showers and thunderstorms south of the front, which could lead to
Special Marine Warnings and/or Statements. Outside of this activity,
south/southeast winds around 10 kt or less today are anticipated to
turn more northerly near/behind the front tonight. Seas will
generally range between 1-3 ft, largest across offshore waters
today.

Monday - Thursday: A cold front will be pushing through the region
Monday morning, pushing the heaviest rainfall south of the area by
the evening. Greater impacts are expected from the switch to
north/northeasterly winds that will be strengthening through the day
and overnight into Tuesday as surface high pressure moves in,
causing marine conditions to worsen quickly. Expect winds to
increase overnight Tuesday into the 25 to 34 knot gusts range,
further strengthening into Gales (35 to 47 knots) Tuesday morning
into Wednesday morning. Storm-force winds can`t be entirely ruled
out Tuesday evening into the early overnight hours, with a 10%
chance for 6 foot waves are expected to quickly move in overnight
into Tuesday morning, with 5 to 6 foot waves pushing up along the
coast by Tuesday afternoon as 9 to 11 ft waves build 20 to 60 nm
offshore as an area of low pressure forms off the GA/FL coast.

Wave heights are expected to slowly subside on Wednesday, with 4 to
5 foot breaker waves along the coast by the evening hours. In the 20-
60nm offshore zones expect 6 to 9 foot waves by the evening hours,
highest in the Savannah to Altamaha Sound zone. Conditions are
expected to improve on Thursday, though rough seas will likely
persist into early Friday especially for the 20 to 60nm offshore
zones. Small Craft Advisories, Gale Watches, and Gale Warnings will
likely be needed. For the Charleston Harbor, a Small Craft Advisory
will likely be needed Tuesday morning into Wednesday morning, with a
10% chance that Gales could sneak into the harbor entrance Tuesday
morning into Tuesday evening.

&&

.CLIMATE...
Record Precipitation:

October 5:
KCXM: 1.17/1915

&&

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

&&

$$

APT/DPB