Area Forecast Discussion
Issued by NWS Charleston, SC
FXUS62 KCHS 081542
Area Forecast Discussion
National Weather Service Charleston SC
1042 AM EST Thu Dec 8 2016
High pressure will prevail today ahead of a strong cold front
that sweeps through the area tonight. Cooler high pressure will
then extend over the area this weekend. A weak cold front should
push through the area early next week before a more significant
cold front affects the area mid week.
.NEAR TERM /THROUGH TONIGHT/...
Today and Tonight: A broad upper trough will shift east toward New
England today while a surface cold front progresses into the South
Carolina Midlands. Satellite imagery shows low clouds have
cleared out across most of the area, but are hanging around a
bit longer across the Charleston Tri-County area. Adjusted the
sky grids across this area to account for this. Also adjusted
the high temperatures downward a bit here because the clouds are
keeping the current temperatures lower than forecasted and that
should limit the afternoon highs. While the low clouds
dissipate, high clouds will stream into the area during the
afternoon. The cold front is expected to shift offshore this
evening with cold air advection and gradual clearing through
tonight. Lows will dip into the mid 30s inland.
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
Friday and Saturday: A large mid/upper trough of low pressure will
shift off the Northeast Coast while sfc high pressure extends over
the Southeast. Expect dry and considerably colder conditions than
previous days as high pressure expands over the area on Friday and
eventually becomes centered over the Mid-Atlantic states on
Saturday. Overall, high temps will be some of the coldest temps so
far this season. In general, expect high temps only in the upper 40s
to lower 50s each day. Friday night lows will be quite chilly,
dipping into the mid/upper 20s away from the coast. Saturday night
lows will show a slightly warmer trend, dipping into the lower 30s
inland to upper 30s/lower 40s near the coast.
Sunday: A coastal trough will develop along the Southeast Coast
early, then lift north while the center of cold high pressure begins
to shift off the Mid-Atlantic Coast. Although most areas are
expected to remain dry, a few showers could drift onshore in
Southeast South Carolina and Southeast Georgia as the trough takes
shape and skirts along the coast. High temps should also be
noticeably warmer to start off the week. However, high temps should
remain somewhat cooler inland where high pressure lingers. In
general, afternoon highs will range in the low/mid 60s near the
coast to upper 50s well inland.
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
A zonal flow will prevail over much of the United States early week
through mid week, setting up a period of quick moving systems and
associated fronts shifting across the Southeast. Expect the first of
two fronts to push through the area on Monday with potentially some
showers over parts of the area. Tuesday will be relatively quiet and
dry while a light southerly wind develops ahead of the next
approaching front. On Wednesday, a more significant cold front will
sweep through the area with showers. Dry and cooler high pressure
will then extend across the region on Thursday.
Overall high temps should range in the upper 60s to lower 70s
Monday, then low/mid 60s Tuesday and Wednesday. By Thursday, high
temps should only peak in the upper 40s to lower 50s. Overnight lows
will generally range in the mid/upper 40s away from the coast Monday
and Tuesday nights. Wednesday night lows should range in the
mid/upper 30s inland to low/mid 40s near the coast.
.AVIATION /16Z THURSDAY THROUGH MONDAY/...
Satellite imagery shows an area of MVFR ceilings across the
Charleston Tri-County area. These clouds will move
northeastward into early this afternoon while dissipating. Expect
VFR at both CHS and SAV this afternoon terminals through 12Z
Extended Aviation Outlook: VFR conditions are expected at both CHS
and SAV terminals. However brief flight restrictions are possible
with a passing cold front Monday.
Today and Tonight: Increasing winds from the west and then
northwest through tonight are expected as a cold front sweeps
through the waters. Strong cold air advection behind the front
will help produce gusts around 25 kt this evening over the
northern South Carolina nearshore waters and offshore Georgia
waters. Additionally, seas will build up to 5-7 ft, highest in
offshore Georgia waters. A Small Craft Advisory will therefore
remain in effect for these waters starting early tonight.
Friday: Cold high pressure will expand across the coastal waters,
allowing Small Craft Advisories to persist over northern South
Carolina waters into late morning and offshore Georgia waters into
early afternoon. A weakening pressure gradient and loss of cold air
advection will then allow conditions to gradually improve to below
Small Craft Advisory levels for the remainder of the day.
Saturday through Tuesday: Conditions are expected to remain below
Small Craft Advisory levels with high pressure extending across the
waters on Saturday. A coastal trough will develop along the Southeast
Coast on Sunday, then lift north of the area into Monday ahead of
a weak cold front that pushes through the region by Monday afternoon.
High pressure will then return to the coastal waters on Tuesday. In
general, winds should gust no higher than 15-20 kt at times as the
coastal trough develops and skirts along the Southeast Coast. A
weaker south/southwest flow should then prevail before turning west
with cold fropa Monday. A light southerly flow should then develop
on Tuesday. Seas will generally range between 2-4 ft through
the period. However, we could have 5 ft seas develop on Sunday
over offshore Georgia waters with the coastal trough.
MARINE...Small Craft Advisory from 9 PM this evening to 2 PM EST Friday
Small Craft Advisory from 9 PM this evening to 11 AM EST
Friday for AMZ350.