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000
FXUS62 KCAE 150747
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
347 AM EDT Mon Oct 15 2018

.SYNOPSIS...
An approaching cold front will be in the forecast area Tuesday
and Wednesday. High pressure will extend into the area from the
north and northeast Thursday and Friday. Another cold front will
be in the region Saturday.

&&

.NEAR TERM /THROUGH TONIGHT/...
Low-level moisture has increased in an onshore flow directed
into the forecast area south of the pressure ridge off the mid-
Atlantic Coast. The moisture should remain shallow because of
upper ridging through today. The MOS was consistent with pops
less than 20 percent. Moisture should become a bit deeper
tonight associated with convergence close to the front nearing
the north part late. We forecasted slight chance pops in the
north section. Farther from the front and closer to stronger
upper ridging the shower chance should be less in the southeast
section. The increased low-level moisture combined with
nocturnal cooling will likely lead to stratus and fog during the
early morning hours. We leaned toward the higher maximum
temperature guidance south of the front today. Used the guidance
consensus tonight.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
Little change made during this period. The upper ridge over the
southeastern states will flatten Tuesday in response to a
digging upper trough moving across the Great Lakes region into
New England. This will allow a cold front to sink southward
across the region Tuesday night into Wednesday. As the front
crosses the region, the best chance for showers across the
Midlands and CSRA will be Wednesday. Precipitable water values
will rise to around 1.8 inches along and just ahead of the front
on Wednesday. However, the best forcing will remain to our north
across VA/NC. MET/MAV pops have trended lower over the past few
runs, but will continue with slight chance/chance pops Tuesday
into Wednesday. Temperatures will continue to average above
normal through the period. The best chances for rain will be
across the northern Midlands along the NC border. Rainfall
amounts will around/less than one quarter of an inch.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
The cold front is forecast to push east of the area by
Wednesday evening as strong high pressure builds in from the
north. Fall weather will return to the region Thu/Fri as cool
and dry high pressure settles over the region. However by Friday
afternoon/night, surface high pressure will quickly move
eastward off the Mid-Atlantic coast. This will shift the low
level flow to a more east/southeast flow over the area by
Saturday. A trough will once again dig across the Great Lakes
into New England Saturday into Sunday. The GFS/ECMWF have
continued to disagree slightly timing with frontal boundary as
it moves into the Midlands and CSRA. However, the best chance
for showers, maybe an isolated thunderstorm, will be on
Saturday. The front will push south of the region Saturday
night and high pressure will once again move over the region.

Temperatures during this period will be near or slightly below
normal Thu/Fri and remain near normal over the weekend. Could
see our coolest morning of the Fall season by Thursday night
with high pressure over the region. Guidance temperatures in
the 40s for many locations.

&&

.AVIATION /08Z MONDAY THROUGH FRIDAY/...
Expect a period MVFR or IFR conditions during the early morning
hours.

Low-level moisture has increased in an onshore flow directed
into the forecast area south of the pressure ridge off the mid-
Atlantic Coast. This moisture combined with nocturnal cooling
should lead to areas of stratus and fog during the early morning
hours. There was inconsistency with the guidance with the NAM
MOS most pessimistic. We leaned toward the NAM MOS because of
the low-level moisture and drying aloft associated with the
upper ridging. Heating and mixing of the shallow moisture should
result in mainly VFR conditions later in the morning and during
the afternoon and evening. The NAM and GFS MOS support wind
mainly southwest less than 10 knots during the day, and light
and variable at night.

EXTENDED AVIATION OUTLOOK...
Widespread mainly late night and early morning MVFR or IFR
conditions associated with a front may occur Tuesday and
Wednesday. Dry ridging should dominate Thursday and Friday.

&&

.HYDROLOGY...
The Congaree River continues to gradually fall and should fall
below flood stage at the Congaree National Park this morning.
Additionally, the Great Pee Dee River is gradually diminishing
and has fallen from moderate flood stage to minor flood stage.
It should fall below flood stage by late tonight or early
Tuesday. Please refer to the latest observations, forecasts,
and flood statements.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.

&&

$$
SYNOPSIS...99
NEAR TERM...99
SHORT TERM...99
LONG TERM...99
AVIATION...99
HYDROLOGY...