Area Forecast Discussion
Issued by NWS Charleston, SC

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FXUS62 KCHS 200224
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
1024 PM EDT Sat Oct 19 2019

.SYNOPSIS...
Low pressure will move northeast through Georgia and South
Carolina tonight. High pressure will briefly build in Sunday
into Monday before a frontal system affects the area Monday
night and Tuesday. High pressure will rebuild late Tuesday
through Thursday before another storm system potentially moves
in late week.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
The remnants of Tropical Storm Nestor are located over south-
central GA with a warm front extending eastward to just north of
Savannah. The low will continue moving northeast through the
CSRA and eastern Midlands overnight while slowly weakening.
Showers and a few thunderstorms, some with heavy rainfall, will
mainly be focused near the low/warm front and over the Atlantic
where instability is greatest. Most of the rain is already over
for eastern portions of southeast GA and chances will be
trending downward from south to north. A low risk of an
isolated tornado remains confined to mainly coastal portions of
central SC where the best combo of low-level instability/shear
are expected through around 2 AM. Otherwise, we have cancelled
the Wind Advisory for the GA coast/coastal Jasper County in SC
but it continues farther north along the SC coast. In addition,
a Lake Wind Advisory remains in effect for Lake Moultrie where
some higher gusts near 25 kt are possible, especially associated
with the heavier rains. The High Surf Advisory also remains in
effect from Beaufort County northward where the stronger onshore
winds should continue to produce at least 5 foot breaking wave
heights. Otherwise, temperatures have been rising slightly this
evening in most places as the warm front progresses to the
north and this trend will continue before they fall late,
especially near the CSRA which should get to around 60 degrees
toward daybreak.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
Sunday: The dampening surface low and mid level short wave will move
northeast of the forecast area. On the back-side of the low,
moisture depth will decrease, however we included some 20/30 POPs
along northwest and northern zones prior to late morning. Otherwise
clouds will decrease in offshore flow throughout the late morning
and afternoon hours. Temps will warm into the mid and upper 70s with
a few 80 degree readings possible to the south of I-16. Monday night
will be dry, while a few models hint at some late night fog and
stratus. Confidence was not high enough yet to work into our
forecast.

Monday: Surface high pressure along the southeast coast will weaken
as a deepening upper trough shifts south and east from the midwest
and Ohio Valley. We maintained a dry forecast as dry air atop 850 MB
looks to hang on. It should be warm in the upper 70s north to lower
80s south.

Tuesday: An approaching cold front is expected to reach the inland
areas before 18Z and likely reaching the coast in the late day. The
12Z/19 runs of the GFS and ECMWF differ by amounts enough to leave
chance POPs in for now. The GFS was showing the better rain chances
Monday night with a warm front passage while the ECMWF highlights
some deep convection during the day ahead of the front. Another warm
day with highs reaching the lower to mid 80s.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
Cooler high pressure will prevail Tuesday night through at
least Wednesday night. Late in the week another deep upper
trough will approach the area, spreading moisture in from the
south and eventually bringing a cold front through the area.
There are large differences in the models regarding the onset of
precipitation. For now we are leaning toward the slower
solution which brings the best coverage of showers to the area
on Friday.

&&

.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
Sub-VFR conditions are expected to persist through tonight into
Sunday. Most of the rain has ended at KSAV but will continue for
several more hours at KCHS until an area of low pressure over
south-central GA progresses north of the area. IFR or lower cigs
and vsbys are expected at both terms at times overnight with
improvement to VFR likely by late Sunday afternoon.

Extended Aviation Outlook: Low potential for stratus and fog at the
terminals late Sunday night and early Monday morning .Otherwise VFR
until brief flight restrictions become possible Monday night into
Tuesday as a frontal system move into the area.

&&

.MARINE...
Tonight: Post-Tropical Cyclone Nestor will lift northeast from
south-central Georgia into the Carolinas overnight. A tight
pressure gradient will support strong southeast winds, and Gale
Warnings remain in effect for all waters, including the
Charleston Harbor. As the low lifts toward the area, a warm
front will shift northward through the waters and the winds
will veer to a more southerly and eventually southwesterly
direction late tonight. The Gale Warnings will come down in
stair-step fashion from south to north, however they will need
to be replaced by Small Craft Advisories.

Winds will continue to veer offshore in the wake of low pressure
to the north Sunday Morning. We will likely need a Small Craft
Advisory for mainly seas along the SC coast with seas subsiding
off the Charleston County coast by mid afternoon. Otherwise, light
winds on Monday with no flags anticipated.

A weak warm front feature is forecast to lift through the waters
Monday night, prior to cold front late in the day on Tuesday. In
the wake of the front Tuesday night into Wednesday, cold air
advection and offshore flow may surge in SCA criteria levels,
especially along outer waters. After mid week, high pressure will
build north of the waters, maintaining a northeast flow.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...Lake Wind Advisory until 2 AM EDT Sunday for SCZ045.
     High Surf Advisory until 5 AM EDT Sunday for SCZ048>050.
     Wind Advisory until 2 AM EDT Sunday for SCZ048>050.
MARINE...Gale Warning until 6 AM EDT Sunday for AMZ352-374.
     Gale Warning until 8 AM EDT Sunday for AMZ350.
     Gale Warning until 4 AM EDT Sunday for AMZ354.
     Gale Warning until 2 AM EDT Sunday for AMZ330.

&&

$$
NEAR TERM...RJB
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...


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