Scientific Forecaster Discussion
fxus62 kchs 101504
Area forecast discussion
National Weather Service Charleston SC
1004 am EST Sat Dec 10 2016
high pressure will prevail until the development and passage of a
coastal trough into Sunday night. A cold front will then shift into
the area Monday night before lingering in the vicinity through mid
week. The front will push offshore Wednesday night and be followed
by cooler temperatures for late week.
Near term /until 6 PM this evening/...
cold high pressure will prevail today. Weak cold air advection
this morning will become neutral this afternoon as mid-level
heights begin to rise. Despite a fairly cold start,
temperatures should recover into the lower to mid 50s for most
locations under sunny skies. Some guidance suggests northern
areas may not break 50, but with a weak downslope flow in place
at 850 hpa, opted not to lower highs in these areas with the
late morning update.
Short term /6 PM this evening through Tuesday/...
tonight: high pressure will extend across the region for much of the
overnight period. However, a weak coastal trough should develop off
the Florida and southeast Georgia coasts late tonight. At this time,
any precip associated with the developing tough is expected to
remain offshore through the overnight period. Some clouds could
advect onshore late, especially in southeast Georgia. Overnight lows
will be warmer than the previous night with increasing cloud cover
from the south late. In general, temps should range in the lower 30s
well inland to mid/upper 30s closer to the coast.
Sunday through tuesday: high pressure centered to the north near
Delmarva will weaken and push offshore Sunday while a trough of
low pressure off the southeast U.S. Coast shifts northward into
Sunday night. This feature will lead to increasing clouds and
possibly a few showers, mainly near the coast. Dense fog will be
possible Monday morning, mainly from the lowering of stratus. A
cold front will then approach the area from the northwest
Monday with breezy conditions likely and some showers possible,
mainly inland toward the csra/midlands. The front looks to push
into the area Monday night and then stall over or near the area
Tuesday and this will keep conditions unsettled with increased
cloud cover and rain chances. A few weak thunderstorms can't be
ruled out Monday through Tuesday given slightly higher
instability. Temperatures should warm through Monday before
cooling Tuesday, although still remaining above normal.
Long term /Tuesday night through Friday/...
low pressure will likely move along the stalled front across the
area keeping it unsettled through Wednesday. Drier conditions are
then expected Wednesday night as high pressure builds in from the
northwest. High pressure should then keep things cool/dry into
Friday before another coastal trough potentially develops and brings
more clouds/showers back into the area. Temperatures should mainly
be near or above normal through Thursday night before possibly
falling below normal Friday, then back near or above normal Saturday
assuming the coastal trough pushes northward as a warm front.
Aviation /15z Saturday through Wednesday/...
VFR conditions will prevail at the chs and sav terminals through
Extended aviation outlook: MVFR cigs/vsbys likely late Sun night into
Mon morning with IFR or lower restrictions possible due to low clouds/fog.
Restrictions likely into Wed due to low clouds/showers.
today and tonight: high pressure will extend over the coastal waters
through much of today and early tonight with conditions that remain
below Small Craft Advisory level conditions. In general, northerly
winds will gust to 15-20 kt through late morning, then gradually
diminish to 10-15 kt over South Carolina waters this afternoon.
A weak coastal trough is expected to develop late tonight along
the Florida and southeast Georgia coasts. A slight enhancement
to the pressure gradient associated with this feature should
support winds that gust up to 15-20 kt at times over offshore
Georgia waters. Otherwise, expect a gradual veering of winds
from the north to the east-northeast late as the coastal trough
takes shape. Seas will range between 2-4 ft through tonight,
highest in offshore Georgia waters.
Sunday through thursday: a weak coastal trough will shift north
through the area through Sunday night. A cold front will then move
into the area Monday night before stalling out over the area or
nearby through mid week. An area of low pressure could develop and
move along the front with conditions possibly nearing advisory
levels at some point for at least a portion of the local waters,
especially the Charleston County and offshore Georgia waters. Also, sea
fog will be possible over the chilly near shore waters, mainly
Monday and Monday night.
coastal flooding...the upcoming lunar perigee and full moon along
with periods of onshore winds could push tides to advisory levels
near times of the early morning high tides Sunday into the middle
of next week, especially along the SC coast.