Area Forecast Discussion
Issued by NWS Charleston, SC

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FXUS62 KCHS 152039
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
339 PM EST Fri Dec 15 2017

.SYNOPSIS...
A dry cold front will move through tonight, followed by high
pressure this weekend. Another front will bring unsettled
weather to the region Monday into Tuesday, then shift offshore
as high pressure rebuilds.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
A cold front will move through this evening as high pressure
builds from the west. Mid and high clouds will diminish from the
north and west as a mid-level shortwave and upper jet to the
north and west shift farther south and east. Clearing skies and
winds inland along with low-level cold advection will allow
temperatures to get near freezing well inland, especially toward
the CSRA. Close to the coast lows should be in the lower- mid
40s.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
Cool high pressure will settle over the area on Saturday,
pushing offshore Saturday night. While high temps will only be
in the upper 50s Saturday, the return flow on Sunday will push
values into the mid/upper 60s.

Sunday night into Monday the upper level flow becomes southwest
and a series of weak shortwaves move into central GA/SC. PWATs
around 1" Sunday afternoon increase to about 1.60" by Monday
afternoon. Moist isentropic ascent will overspread inland areas
late Sunday night, expanding across more of the area on Monday.
Scattered showers Sunday night will become numerous across
inland areas on Monday where the greatest forcing and moisture
will overlap. Strong low-level warm air advection will another
unseasonably warm day with highs in the upper 60s to lower 70s.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
The front will slowly move across the Southeast Monday night into
Tuesday, bringing our area unsettled weather. By Wednesday there is
a split in the models. Some of them move the front offshore and
have dry high pressure building in from the north. The rest
keep the area damp due to remnants of the front remaining nearby
along with low pressure forming offshore. Since the majority of
the models have the drier forecast, that`s what we trended
towards on Wednesday. By Thursday moisture starts moving in from
the south, leading to an increased threat of showers.

&&

.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
VFR. Could see some wind gusts into the upper teens this
afternoon though as the low-level jet increases ahead of an
approaching cold front.

Extended Aviation Outlook: Flight restrictions likely from
Monday afternoon through Tuesday or Wednesday as a front affects
the area.

&&

.MARINE...
Tonight: A cold front will push through the area which will
cause westerly winds to shift to the north-northwest with a modest
surge, mainly up to 20 kt. Could see a few gusts to 25 kt,
mainly over the Charleston County nearshore waters and offshore
GA waters. Seas will build slightly but be limited due to the
offshore fetch, mainly peaking around 3 feet in the near shore
and 4-5 ft in the offshore waters.

Saturday through Wednesday: High pressure will prevail Saturday
through Monday before a cold front slowly approaches from the
west. The front will eventually move offshore by late Tuesday or
Wednesday. Winds/seas will be quite low over the weekend, then
gradually increase early next week as the gradient strengthens.
However we still show conditions remaining well below advisory
levels through the middle of next week.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...None.

&&

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


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