Area Forecast Discussion
Issued by NWS Charleston, SC

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FXUS62 KCHS 080922

Area Forecast Discussion
National Weather Service Charleston SC
422 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.


A broad upper trough will shift east toward New England today
while a surface cold front progresses into the SC Midlands.
Morning clouds will clear out around daybreak though mid and
high clouds will stream in during the afternoon. Downslope flow
and pre-frontal compression will push highs into the middle 60s
near the coast while farther inland we see highs in the lower
60s. The cold front shifts offshore this evening with cold
advection and gradual clearing through tonight. Lows will dip
into the mid 30s inland.


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.


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.


Strengthening westerly flow in the low levels is bringing some
drier air into the area. The risk for flight reductions will
diminish toward daybreak as the lower ceilings push east of both
terminals. VFR expected thereafter with winds becoming northwest

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.


Increasing winds from the west and then northwest through
tonight as a cold front sweeps through the waters. Gusts to 25
kt become increasingly likely this evening over the Charleston
nearshore waters, and both 25 kt gusts and 6-7 ft seas over the
offshore GA waters, thus necessitating Small Craft Advisories
for both zones.

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
     for AMZ374.
     Small Craft Advisory from 9 PM this evening to 11 AM EST
     Friday for AMZ350.


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