North Charleston, South Carolina 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

613
FXUS62 KCHS 090809
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
409 AM EDT Fri Oct 9 2026

.WHAT HAS CHANGED...
Increasing confident that this morning`s high tide will remain below
minor flood stage for the Charleston area. Increasing confidence in
gusty northeast winds Saturday morning, bringing the potential for
major coastal flooding to portions of the area. The risk for flash
flooding and tornadoes remains unchanged for Saturday.

&&

.KEY MESSAGES...
- 1) Moderate to Major coastal flooding expected with the
  Saturday morning high tide, with additional coastal flooding
  possible through the weekend.

- 2) Hurricane Isaias is expected to approach the northern Gulf
  Coast late today, before shifting across the Deep South on
  Saturday. Although the center of the storm will remain well
  west of the region, heavy rainfall is likely across Southeast
  Georgia and the South Carolina Lowcountry this weekend. Flash
  and urban flooding is possible.

- 3) A few tornadoes are possible across Southeast Georgia and
  Southeast South Carolina Saturday.

&&

.DISCUSSION...
KEY MESSAGE 1: Moderate to Major coastal flooding expected with the
Saturday morning high tide, with additional coastal flooding
possible through the weekend.

Persistent northeast wind and Saturday`s new moon will combine to
bring elevated high tides into Sunday. Here is a breakdown of each
high tide:

Friday AM: There is increasing confidence that this morning`s high
tide will peak just below minor flood stage in the Charleston Harbor
again as departures have diminished further. A Coastal Flood
Advisory is not expected at this time.

Friday PM: Northeast winds increase through the day, driving
departures higher. However, the astro tide value will be lower than
the morning high tide, potentially offsetting the increased tidal
departure. Expect high tide to peak near minor flood stage for the
Charleston and Colleton County Coastlines.

Saturday AM: The tide cycle of greatest concern as gusty northeast
winds could drive departures significantly higher through the early
morning hours. The astro tide value for the Charleston Harbor is
into Action Stage by itself, so, conceptually, gusty northeast winds
could be sufficient to push the high tide to the 8 ft MLLW major
coastal flooding threshold for the Charleston and Colleton County
coastlines. Additionally, the threat for heavy rainfall will
increase through the morning, potentially exacerbating flooding
problems for Downtown Charleston. Further south, Minor to moderate
coastal flooding is expected along the Georgia and Beaufort County,
SC coastlines.

Saturday PM: Northeast winds begin to diminish, but elevated tidal
departures persist. Minor to moderate coastal flooding likely for
the Charleston area, with lingering rainfall again bringing the
threat of compounded flooding impacts. Further south, high tide is
most likely to remain below minor flood stage for the
Savannah/Beaufort area.

Sunday AM: Southerly winds will bring significantly diminished tidal
departures, though minor coastal flooding remains possible for the
Charleston area.

Rip Currents/High Surf/Beach Erosion: Increasing northeasterly winds
and building wave heights bring a High Risk of rip currents along
the southeast Georgia beaches today. Then, tomorrow, expect High
Risk of rip currents across all area beaches. The elevated swell and
flooding high tides may lead to areas of significant beach/dune
erosion.

KEY MESSAGE 2: Hurricane Isaias is expected to approach the northern
Gulf Coast late today, before shifting across the Deep South on
Saturday. Although the center of the storm will remain well west of
the region, heavy rainfall is likely across Southeast Georgia and
the South Carolina Lowcountry this weekend. Flash and urban flooding
is possible.

NHC expects Hurricane Isaias to approach the northern Gulf Coast
late today, before shifting across the Deep South Saturday. As this
process unfolds a deep plume of tropical moisture will be drawn
northward across the Southeast United States starting this evening
with rounds of showers and thunderstorms anticipated locally early
Saturday into early Sunday prior to a cold front arriving from the
west later Sunday morning.

For today, much of the area remains dry into mid-late morning hours
while a wedge of high pressure holds across the Carolinas into
Georgia inland. The exception will be for areas well south near the
Altamaha River and coastal Georgia where moisture first arrives,
with activity generally in the form of moderate showers. Expect
activity to slowly expand north during afternoon into early evening
hours as favorable isentropic ascent develops across the region and
PWATs in excess of 2.0 inches arrive between the wedge front
inland and a weak front/coastal trough approaching from the south.

Saturday into early Sunday: Numerous to widespread showers with
embedded thunderstorms should be ongoing before daybreak Saturday as
a weak warm front approaches the Altamaha River early and further
north into Southeast Georgia prior to sunrise, before continuing
north across the local area during the day. The position of the warm
front will likely contribute to the bulk of enhanced precip activity
for the day, with an uptick in rainfall rates while PWATs peak (2.25-
2.40 inches), potentially supporting minor and/or localized flash
flooding within activity across saturated grounds, especially if
coinciding with Saturday high tide cycles. The greatest risk for
flooding remains across coastal counties of Southeast South
Carolina, where a slightly longer duration of moisture convergence
occurs with the nearby front/coastal trough. Given some tendency
weighted towards this solution, we have refined rainfall totals to 1-
3 inches inland and across Southeast Georgia and 3-5 inches with
isolated higher amounts possible across coastal counties of
Southeast South Carolina. A Flood Watch could eventually be issued
later this morning for parts of Southeast South Carolina for
Saturday morning into Saturday night. The latest WPC Excessive
Rainfall Outlook places Southeast South Carolina and Southeast
Georgia in a Slight Risk for excessive rainfall on Saturday.

Sunday: Confidence in overall shower and thunderstorm activity is
quite a bit less to start early week, highly dependent on the
arrival of a h5 shortwave and cold front to start off next week.
However, moisture supply is likely to remain within a southerly flow
until fropa occurs. Although minor and/or flash flooding is not
expected during this time period, brief heavy downpours are possible
with activity shifting offshore late morning.

Key Message 3: A few tornadoes are possible across Southeast
Georgia and Southeast South Carolina Saturday.

Latest guidance continues to support a potential for tornado
activity within a warm sector well to the east of Isaias shifting
across the Deep South and towards Tennessee. The threat for
tornadoes increases locally during early morning Saturday, as winds
veer from the east in advance of a warm front. Coastal areas of
Southeast Georgia could see the first of this activity during
predawn hours Saturday, when SBCAPE (~1000 J/kg), 0-3km SRH (~250
m2/s2), 0-6km bulk shear (~40kt) and a slight backing of the sfc
wind occurs near the warm front shifting north. The latest HREF
paintball plots also show a signal for this type of activity closer
to the coast during early morning hours, and gradually shifting
north into coastal Southeast South Carolina late morning. Despite
widespread cloud cover and precip activity, instability levels
should gradually increase across inland areas as a wedge of high
pressure erodes and sfc winds gradually turn more southerly through
late day. Although the risk for tornadoes appears less likely
Saturday afternoon due to the departure of the warm front, there
remains a risk for such activity within the warm sector displaying
deep tropical moisture, with perhaps a secondary increase in tornado
threat ahead of/near a cold front shifting through the region late
Saturday night/early Sunday.

&&

.AVIATION /07Z FRIDAY THROUGH TUESDAY/...
VFR conditions are expected at CHS/JZI/SAV terminals through 00Z
Saturday. Gusty easterly winds and showers should begin
impacting the SAV terminal between 00-06Z Saturday with
previaling MVFR restrictions likely. A few thunderstorms could
arrive at SAV Saturday night as well, producing MVFR/IFR
conditions. At CHS/JZI, the risk for flight restrictions
increases Saturday night as well, with PROB30 groups in the
00-04Z range at both sites, followed by prevailing MVFR
conditions and showers after midnight.

Extended Aviation Outlook: Flight restrictions are likely at all
terminals Saturday morning through Sunday with widespread
showers and/or thunderstorms, some capable of heavy downpours
and gusty winds.

&&

.MARINE...
Friday: See NHC forecast for the latest on Hurricane Isaias. For our
region, the pressure gradient will increase between a high pressure
to our north and the hurricane to our southwest as it travels
northwards. This is expected to strengthen the northeast winds
Friday morning into the afternoon hours, with wave heights building
as well. The wind speed forecast has trended slightly weaker, and
persistent gale conditions are now unlikely across GA coastal waters
where a Small Craft Advisory has been issued.

Friday night into Saturday: Combination of inland ridging and
developing coastal troughing as a warm front moves up from the south
will bring Gale conditions to the SC coastal waters. Strongest winds
will be on the west side of a coastal boundary expected to linger
offshore, with the GA waters remaining south of this coastal
boundary and unlikely gust above 30 kt. Moderate southernly flow
develops later Saturday as the warm front lift north of the area.

Lake Moultrie: Wind gusts across Lake Moultrie expected to reach 30
kts  Saturday morning. A Lake Wind Advisory has been issued
accordingly.

Sunday into Monday: The surface high pressure gets pushed off into
the Atlantic as the remnant surface low pressure of Isaias is
expected to push off into the northeast states before moving
offshore. This will likely keep winds breezy on Sunday as southerly
winds move in, with breezy westerly winds on Monday. Currently,
expecting at least Small Craft Advisory conditions to persist into
Sunday, with a non-zero chance for them to continue to portions of
Monday.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...High Risk for Rip Currents from 8 AM EDT this morning through this
     evening for GAZ217-219-239-241.
SC...Lake Wind Advisory from 5 AM to 2 PM EDT Saturday for SCZ045.
MARINE...Small Craft Advisory from 3 AM Saturday to 1 AM EDT Sunday for
     AMZ340.
     Gale Warning from 10 PM this evening to 10 PM EDT Saturday for
     AMZ360.
     Gale Warning from 7 PM this evening to 10 PM EDT Saturday for
     AMZ362.
     Small Craft Advisory from 11 AM this morning to 1 AM EDT
     Sunday for AMZ364-384.
     Gale Warning from 10 PM this evening to 4 AM EDT Sunday for
     AMZ380.
     Gale Warning from 7 PM this evening to 4 AM EDT Sunday for
     AMZ382.

&&

$$

CEB/DPB