Area Forecast Discussion
Issued by NWS Charleston, SC

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FXUS62 KCHS 191424
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
1024 AM EDT Thu Oct 19 2017

.SYNOPSIS...
Strong high pressure will build over the area through Saturday,
then shift off the coast. A cold front will move through the
area on Tuesday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 1025 AM: The only changes with this update were to adjust
the temperature, dew point, and sky cover grids slightly to
reflect the current observations and the expected trends for the
next few hours. Everything else is on track.

A weak H5 trough will ripple over the CWA late this afternoon
and this evening. During the overnight hours, the center of 590
DM ridge will drift east over the Deep South, the ridge axis
north over the southern Appalachians. At the sfc, high pressure
is expected to remain centered over the western Carolinas,
building slightly east. The air mass will remain dry, PW around
.70 today decreasing to less than .5 tonight. Expect clear to
mostly clear skies. Any cloud cover and mentionable POPs will
remain over the marine areas. Using a blend of temperature
guidance, high temperatures are forecast to range around 80
degrees this afternoon and cooling into the 50s tonight.

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY/...
A deep layered ridge will remain over the southeast United
States Friday into Saturday before shifting off the coast on
Sunday. As the surface high shifts off the coast late Saturday
through Sunday, onshore flow will develop and low-level
dewpoints will rise into the 60s. A weak coastal trough
developing over the Georgia waters may produce isolated showers,
potentially shifting into coastal Georgia Saturday night. A weak
shortwave approaching the area from the west, combined with
deepening moisture, may produce scattered showers or an isolated
thunderstorm on Sunday. High temps are expected to reach the low
to mid 80s each day, highest far southwest.

&&

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
A potent upper low will affect the area Monday into Tuesday,
pushing a cold front through the area late Tuesday. Good chance
for showers and tstms along and ahead of the cold front,
followed by drying and eventually cooler temps as high pressure
builds from the west and north.

&&

.AVIATION /14Z THURSDAY THROUGH MONDAY/...
VFR.

Extended Aviation Outlook: VFR conditions are expected at both
CHS and SAV terminals through this weekend.

&&

.MARINE...
Today and Tonight: Winds and seas will remain elevated into this
afternoon given a continued pressure gradient across the local
waters, 2-3 mb spread from near the Santee River and the Altamaha
River. The pressure gradient will begin to relax over the
coastal waters during the mid and late afternoon while high
pressure builds east. As a result, northeast winds will
gradually weaken late today into tonight. Seas will also slowly
subside. Winds/seas should drop below Small Craft Advisory
levels this afternoon in nearshore waters, lingering across the
offshore Georgia waters.

Moderate NE winds will persist through the weekend before
shifting to E and eventually SE early next week as the surface
high pressure system pushes off the Mid-Atlantic coast. Seas
should drop below 6 ft over the offshore GA waters late Fri
afternoon, but will likely build back above 6 ft Sunday through
early to mid next week due to increasing fetch.

Rip Currents...Steady northeast winds, long period swell from the
northeast/east, and new moon influences will support an elevated risk
of rip currents through late this week. A moderate risk of rip
currents will continue for all beaches today.

&&

.TIDES/COASTAL FLOODING...
Persistent northeast winds and astronomical factors will lead to
a risk for minor coastal flooding during the morning high tides
through Saturday, mainly in Southeast SC.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...Small Craft Advisory until 2 PM EDT this afternoon for AMZ352-
     354.
     Small Craft Advisory until 6 PM EDT Friday for AMZ374.
     Small Craft Advisory until 5 PM EDT this afternoon for AMZ350.

&&

$$
NEAR TERM...
SHORT TERM...
LONG TERM...JRL
AVIATION...
MARINE...
TIDES/COASTAL FLOODING...



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