118
FXUS62 KCHS 181801
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
201 PM EDT Mon Aug 18 2025

.SYNOPSIS...
Weak high pressure will build into the region early this week
as Hurricane Erin passes well offshore through the middle of
the week. The pattern may become more unsettled again late week
and into this weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
The mid-levels will consist of a large High to our west and
Hurricane Erin well to our southeast. At the surface, a weak
front will be located to our north with Hurricane Erin well to
our southeast. There`s not much moisture in place for this time
of year and minimal instability. Aside from an isolated shower
into early this evening, the NBM keeps our area dry later this
evening and overnight. Low temperatures will be in the low to
mid 70s.

&&

.SHORT TERM /TUESDAY THROUGH THURSDAY/...
Powerful Hurricane Erin is forecast by NHC to remain well
offshore/east of our coastline through this period. However,
given the strength and trajectory of the storm, increasing long
period swells will move into the coastal waters later today, and
persist into Thursday. The long period swell will also result
in strong/deadly rip currents. Thus, a High Risk of Rip Currents
has been issued for Tuesday. The high risk for Rip Currents
will likely persist at least through Wednesday and possibly
Thursday. The long period swell is also expected to produce
increasing breaking wave heights of 5+ feet along the coast.
Therefore, have issued a High Surf Advisory for the entire coast
Tuesday through Thursday.

Outside of Erin, the area is expected to remain between a nose
of high pressure inland and the deep low center associated with
Erin well to the east. Model blends indicating scattered to
numerous afternoon/evening showers and thunderstorms across much
of the area on Tuesday, with the highest coverage expected to
be just inland of the coast. Deep layer moisture looks to
decrease on Wednesday and even Thursday, lowering the chances
for convection. Right now, PoPs for Wednesday and Thursday
15-20%, lowest for Thursday. Temperatures near to slightly above
normal, especially over our SE GA zones. Humidity levels will
be lower than past several weeks.

&&

.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
The center of Erin continues to move NNE well away from the
region. Meanwhile, deep layer ridging builds over the OH River
Valley, leaving much of the SE U.S. in a weak flow region, with
possibly weak upper level disturbances. Blended solutions point
toward a marked increase in deep layer moisture. This is
expected to translates to increasing rain chances, especially
during the afternoon/evening timeframe each day. With weak
steering flow and increased deep layer moisture, the threat for
locally heavy rainfall and flooding will also be increasing
during this period. Given increasing clouds/rain chances,
temperatures are expected to be near to below normal through the
period, especially the high temperatures.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
VFR.

Extended Aviation Forecast:
Tuesday: Brief flight restrictions possible all sites from late
morning to mid afternoon with scattered showers and
thunderstorms.

Wednesday and Thursday: Slightly drier deep layer
conditions will lower chances for afternoon
showers/thunderstorms.

Friday: Scattered to numerous mainly
afternoon and evening showers and thunderstorms with flight
restrictions possible.

&&

.MARINE...
Through Tonight: Swells associated with distant Hurricane Erin
have started moving through the waters and will continue to
increase. Small Craft Advisories are in effect for all of the
ocean waters, except the Charleston Harbor starting tonight.

Hazardous marine conditions are expected to persist at least through
Thursday as the center of powerful Erin moves well east of the
waters. Small Craft Advisories are in place for all waters through
much of the period, except for Charleston Harbor. The SCAs are
largely due to increasing long period swells/waves, with seas 8-12
feet within 20 nm and 12 to 15 feet beyond 20 nm, decreasing
Thursday and Friday. NE winds 15 to 20 kts with gusts to 25 kts
Tuesday, then gradually veering to northerly Wednesday and northwest
by Thursday. Strongest winds expected to be Tuesday through
Wednesday night, then decreasing Thursday and Friday.

Rip Currents/High Surf: Swells associated with distant
Hurricane Erin have started moving through the waters and will
continue to increase. A Moderate Risk of rip currents is in
effect at all of our beaches through this evening. A High Risk
of rip currents is in effect for all of our beaches on Tuesday.
A High Surf Advisory is in effect Tuesday through Thursday.

&&

.TIDES/COASTAL FLOODING...
Increased swell and northeasterly winds associated with
Hurricane Erin passing well offshore will likely result in
higher tidal levels Tuesday and Wednesday. Tide levels could
reach at least minor coastal flooding with the evening high tide
cycles. Tide levels may reach moderate coastal flood levels by
the Wednesday evening high tide at the Charleston gauge. Coastal
Flood Advisories are looking more likely for this period for
much/all of the coast.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...High Risk for Rip Currents from Tuesday morning through Tuesday
     evening for GAZ117-119-139-141.
     High Surf Advisory from 8 AM Tuesday to 8 PM EDT Thursday for
     GAZ117-119-139-141.
SC...High Risk for Rip Currents from Tuesday morning through Tuesday
     evening for SCZ048>051.
     High Surf Advisory from 8 AM Tuesday to 8 PM EDT Thursday for
     SCZ048>051.
MARINE...Small Craft Advisory from 4 AM Tuesday to 2 PM EDT Friday for
     AMZ350-352-354.
     Small Craft Advisory from midnight tonight to 8 AM EDT
     Saturday for AMZ374.

&&

$$

NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...