Bluffton, South Carolina Weather Forecast Discussion

697
FXUS62 KCHS 211111
AFDCHS
Area Forecast Discussion
National Weather Service Charleston SC
711 AM EDT Sun Sep 21 2025
.SYNOPSIS...
High pressure will prevail through early next week. A coastal
trough could form near the coast during the middle of next
week, then a cold front will approach from the west late in the
week.
&&
.NEAR TERM /THROUGH TONIGHT/...
Today: Aloft, weak ridging will ripple through ahead of a
southern stream trough across the lower MS Valley. At the
surface, high pressure across New England this morning will
begin to slip to the east while still extending across the
forecast area through the day. The inland high will weaken
through the day which should allow for near surface flow to turn
from northeasterly in the morning to more easterly later in the
day. There is good model agreement between the hi-res solutions
and the HREF that there will not be any diurnal convection
today. Model soundings reveal very warm profiles in the mid-
levels, effectively limiting the potential for destabilization
and diurnal convection. Highs are forecast to be slightly above
normal with mid to upper 80s across southeast SC and upper 80s
to 90 for southeast GA.
Tonight: The inland high will persist and model guidance
continues to support a dry forecast. Lows are forecast to dip
into the mid 60s inland, ranging to the upper 60s and low 70s as
you get closer to the coast.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
Monday: The upper level low over Saskatchewan will slowly move
southeast towards the Great Lakes which will help to amplify the
southern stream energy across the northern Gulf of America. At
the surface, an area of high pressure over New England will edge
down across the Carolinas with a coastal trough developing. In
the wedge, PWATs fall off to around 1.35". However, the coastal
trough will try and move inland Monday afternoon with moisture
rich air (PWATs > 1.75") surging across coastal Georgia. This
makes sense as the aforementioned upper level pattern firmly
places coastal Georgia and South Carolina in the diffluent zone
of the approaching trough. As such, chance PoPs are in the
forecast for coastal Georgia, with only very low chances of
precipitation for South Carolina (and inland Georgia).
Tuesday: Surface high pressure that was over New England will
drift southeast towards Bermuda. The CAD will collapse Tuesday
afternoon with the coastal trough also washing out. Southeast
winds will reestablish themselves across all zones with humidity
values slowly starting to move up. The upper level trough from
Monday will also be progressing northeast with the trough axis
located directly overhead. A small chance of precipitation does
exist for Tuesday, but the most likely scenario is for a
majority of the region to remain dry as the diffluent side of
the trough axis is east of the area. Highs will be in the upper
80s for South Carolina and low 90s for Georgia.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
Global ensembles are in fairly good agreement for the extended
with the EPS, GEFS, and GEPS all showing an upper level low
entering the Pacific Northwest Sunday afternoon and then
constructively amplifying over the southwest Ohio River Valley
Friday into Saturday. Where global ensemble guidance differs is
how fast the wave moves east with an associated cold front and
unsettled weather. Ensemble guidance generally shows the closed
baroclinic low slowly filling and becoming barotropic just west
of the region. However, significant uncertainty exists in next
weekends forecast. In this type of setup, generally a slower
progression is favored.
Out ahead of the deepening closed low will be mid-level
ridging. The latest run of the NBM shows temperatures reaching
into the mid 90s by Thursday with a slight cooling trend Friday
along with a return of precipitation for Friday and Saturday.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
VFR conditions are expected to prevail at KCHS, KJZI, and KSAV
through 12z Monday.
Extended Aviation Forecast: Mainly VFR expected through
Wednesday. The chance of afternoon showers and thunderstorms
returns on Thursday.
&&
.MARINE...
Today through tonight: A pattern that features high pressure
inland and a surface trough offshore will support northeast flow
across the local waters through the period. The gradient will
be tight enough to yield wind speeds in the 15-20 knot range,
with some gusts into the low 20 knot range. Seas will gradually
increase through the day and should mostly peak in the 3-5 ft
range. Overall, conditions should remain just below Small Craft
Advisory levels, but could get close at times in the Charleston
County waters and the outer GA waters.
Monday: High pressure over New England will begin to move east
with the wedge over the Piedmont and coastal waters starting to
dislodge. As this occurs, a weak coastal trough will try to form
with winds temporarily increasing in speed from the northeast
15 to 20 kt. Seas will also respond slightly upward 3 to 5 ft,
but Small Craft Advisories are not expected to be needed.
Tuesday and Wednesday: The coastal trough will fall apart in
the afternoon as surface high pressure becomes established
northwest of Bermuda. Winds over the waters will veer from the
southeast and decrease in speed 5 to 10 kt. Seas will also start
to relax 2 to 4 ft.
Thursday: An upper level low and cold front will start to
approach the area from the west. Showers and thunderstorms will
return to the waters with winds and seas slowly ticking upwards.
This type of setup generally favor a slowing trend, meaning the
showers and thunderstorms might hold off until Friday.
Rip Currents: The combination of elevated northeast winds along
the coast and moderate swell energy will yield a Moderate Risk
of rip currents at all beaches today. A moderate risk of rip
currents will prevail at all area beaches Monday due to the
elevated northeast winds.
&&
.TIDES/COASTAL FLOODING...
The risk for minor coastal flooding should continue into early
next week. Coastal Flood Advisories could eventually be needed
for minor saltwater flooding in Charleston and Coastal Colleton
Counties.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...None.
&&
$$
NEAR TERM...BSH
SHORT TERM...Haines
LONG TERM...Haines
AVIATION...BSH/Haines
MARINE...BSH/Haines

NWS CHS Office Area Forecast Discussion