691
FXUS62 KCHS 071107
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
707 AM EDT Mon Sep 7 2026

.WHAT HAS CHANGED...
The Aviation section was updated for the 12z TAF issuance.

&&

.KEY MESSAGES...
- 1) Scattered showers and thunderstorms could impact portions
  of southeast South Carolina and southeast Georgia today. The
  best chance for locally heavy rainfall will be along the
  coast.

- 2) Coastal flooding is expected at least through the middle
  of the week, especially along portions of the southeast South
  Carolina coast.

&&

.DISCUSSION...
KEY MESSAGE 1: Scattered showers and thunderstorms could impact
portions of southeast South Carolina and southeast Georgia
today. The best chance for locally heavy rainfall will be along
the coast.

With high pressure to the north and weak low pressure near the
northeast FL coast, northeast will will prevail across the area
today. By mid to late morning we should start to see either
showers and storms develop over the coastal waters or along the
coast. These showers and storms should be scattered in coverage
and move to the southwest and west-southwest within the
aforementioned flow pattern. By the afternoon, we should start
to see some lower precipitable water values push in from the
northeast (~1.5 inches) while areas down across the lower SC
coast and southeast GA sit within a more moist environment (~2
inches). There will be some potential for locally heavy
rainfall, primarily along the coast from around Beaufort County
south to the Altamaha. The overall flood risk is relatively low
but it is possible a few locations could pick up 1-2 inches of
rain. If this locally heavy rain were to occur around the time
of the late afternoon high tide (~5:45 pm) the flood risk could
be slightly enhanced along the coast.

KEY MESSAGE 2: Coastal flooding is expected at least through
the middle of the week, especially along portions of the
southeast South Carolina coast.

Astronomical tide levels will continue to rise through the
middle of the week thanks to the recent lunar perigee (9/6) and
the upcoming new moon (9/11). These factors will push
astronomical tides as high as 6.55 ft MLLW at Charleston
Wednesday evening, setting the stage for coastal flooding
potential with each evening high tide cycle. Northeast flow will
strengthen along the coast today and persist into Tuesday night
which is expected to drive increasing tidal departures. The
first round of coastal flooding is expected to occur with the
upcoming late afternoon high tide at Charleston (~5:45 pm) and
we are currently forecasting a peak tide value of 7.3 ft MLLW.
The potential for moderate coastal flooding (7.5ft MLLW or
higher) will increase with the Tuesday and Wednesday evening
high tides as tidal departures likely build within the
persistent northeast flow. Coastal Flood Advisories will almost
certainly be needed for Charleston and coastal Colleton counties
with each late afternoon and early evening high tide cycle
through at least Wednesday.

For the rest of the coast from Beaufort County south including
the southeast GA coast, tidal departures would need to exceed 1
ft to reach the minor coastal flood threshold (9.5 ft MLLW) at
Fort Pulaski. Therefore, coastal flooding is less likely along
this part of the coast but can`t be ruled out especially with
the late afternoon and early evening high tide cycle on Tuesday
and Wednesday.

&&

.AVIATION /12Z MONDAY THROUGH FRIDAY/...
The 12z TAF period begins with mostly IFR conditions around the
area. KCHS and KSAV are currently IFR while KJZI has been a bit
more variable over the last few hours. IFR stratus should lift
to MVFR by around mid to late morning, transitioning to MVFR for
a bit before VFR. Also, northeast winds are expected to become
breezy with gusts up to around 20 knots starting around mid
morning. Regarding shower and thunderstorm potential, we expect
to see activity either spread inland from the coastal waters or
develop along the coast and then track to the west-southwest.
Current thinking is that most of the activity should just scoot
by KCHS and KJZI to the south, meaning that KSAV likely has the
best chance of seeing a shower or thunderstorm. We have
maintained the PROB30 at KSAV in the 18-21z time period.

Extended Aviation Outlook: Scattered thunderstorms could impact
the terminals again on Tuesday. Northeast winds will be breezy
on Tuesday as well.

&&

.MARINE...
Today and tonight: Northeast flow will continue to surge across
the local waters this morning with the strongest flow across
the SC nearshore waters. A solid 15-20 knots is expected across
all waters, with frequent gusts to around 25 knots in the SC
nearshore waters and for a shorter period of time in Charleston
Harbor. Seas will build in response, becoming 3-5 ft across the
SC waters and 3-4 ft for the GA waters. Small Craft Advisories
are in effect for the SC nearshore waters and Charleston Harbor.
Overnight, winds should diminish just a bit in the early
morning hours which will allow for the ongoing Small Craft
Advisories to likely come down. But we still expect to see
persistent 15-20 knots of flow.

Tuesday through Friday: Northeast flow across the local waters
is expected to surge a bit on Tuesday with gusts to 25 knots
becoming more frequent across all the nearshore waters and
possibly even Charleston Harbor. The ongoing Small Craft
Advisories will either need to be extended in time or new
advisories will be needed for much of the waters through Tuesday
evening. The gradient will begin to weaken and diminish Tuesday
night through Wednesday. For Thursday and Friday we expect to
see a return to southwest flow.

Rip Currents: Persistent and gusty northeast winds and building
seas will support a Moderate Risk of rip currents at all
beaches along the southeast SC and southeast GA coast today.
Then for Tuesday, increased swell energy and continues gusty
northeast winds will result in at least a Moderate Risk of rip
currents again. There is even some support for a High Risk.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...Coastal Flood Advisory from 4 PM this afternoon to 8 PM EDT
     this evening for SCZ149-150.
MARINE...Small Craft Advisory from 11 AM this morning to 7 PM EDT this
     evening for AMZ340.
     Small Craft Advisory from 11 AM this morning to 2 AM EDT
     Tuesday for AMZ360-362.

&&

$$