Area Forecast Discussion
Issued by NWS Wilmington, NC

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FXUS62 KILM 240950
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
450 AM EST Fri Nov 24 2017

.SYNOPSIS...
Low pressure passing offshore this morning, will move further
away from the area this aftn allowing dry high pressure to
dominate tonight into Saturday. A dry cold frontal passage will
occur Saturday night followed by modified Canadian high pressure
Sunday through the early to mid-week period of next week.
Temperatures up to this point in time will run near the climo
norms for this time of the year. A milder trend will occur late
next week as high pressure moves offshore and low pressure
approaches from the west.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 300 AM Friday...Low pressure passing off shore will get
nudged farther east as H5 shortwave swings east through today.
Any significant lift and measurable pcp will remain well off
shore but mid to high clouds will continue to stream up along
the immediate coast in SW flow aloft through this morning. Once
the shortwave shifts east the winds come around to a more
westerly direction, drier air will move toward the coast
allowing clouds to thin out and clear by this afternoon.
Enhanced lift in tightened gradient flow this morning will
produce help to produce some lower clouds around 3k ft but all
clouds will diminish as low pressure moves farther off to the
E-NE. Overall expect any lingering light pcp and clouds along
the coast to break up through early this afternoon while most of
the area inland will be very dry through today with plenty of
sunshine.

A large temperature spread exists this morning with drier air
and lighter winds inland with readings in the mid 30s, while
clouds and greater moisture closer to the coast were holding
temps up in the mid 40s. The sunshine inland will help bring
temps up into the 50s to near 60 for highs this afternoon while
temps along the coast will see a slower rise this morning with
the cloud cover. By this afternoon temps should rebound in
increasing sunshine along the coast bringing all temps up
around 60 for highs this afternoon.

High pressure over the area will shift eastward through tonight
allowing winds to back slowly by morning. Basically expect a
dry air mass in place with near calm winds and mainly clear
skies. This will produce more ideal radiational cooling with
temps dropping into the mid 30s most places, except closer
to 40 right along the coast.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
As of 330 AM Friday...Overall longwave pattern aloft not to
change much this period. This pattern includes low amplitude
upper troffing affecting the U.S. east of the Mississippi River
Valley and low to mid amplified upper ridging west of the
Mississippi to the Pacific Coast. Main storm tracks to remain
across Canada with occasional lows traversing along the US-
Canada border ie. across the Great Lakes and the NE States.

Looking at a quiet weekend weather-wise. The only highlight
will be a cold frontal passage slated for late Sat evening into
the pre-dawn Sun hrs before moving off the Carolina Coasts
altogether by daybreak Sun. The low attached to this lengthy
cold front will be in Eastern Canada at the time of this CFP.
With the cold front well displaced from the dynamics associated
with the low, will have to turn to it`s own frontal dynamics as
the primary forcing, which will be enough for cloudiness, but
just too weak for any pcpn development. With no tapping of any
major moisture source pools, ie. Gulf of Mexico or Atlantic
Waters, will have to rely on the moisture accompanying the cold
front. And this moisture will be quite limited especially after
it crosses the Appalachians where scouring will occur due to the
downslope trajectories. With all this said, have kept POPs null
and void thruout this fcst period which includes the CFP. Skies
in general this period will be mostly clear/sunny with partly
or variably cloudy skies during the CFP Sat night or early Sun.
Temperatures thruout this period will run near climo norms. Not
all that dramatic with this CFP, not much in the way of CAA but
more in the way of wind direction changes and drier air influx
ie. lower dewpoints with much of that having to do with the
downslope wind action.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
As of 228 PM Thursday...Intrusion of Canadian high pressure to
dominate the first half of the extended period, remaining
exceptionally dry through Monday, although winds do ease Monday
as the surface high centers over the area. Monday morning will
be the chilliest portion of this period, with widespread 30s and
sub-freezing air over parts of the interior. Tuesday through
Thursday look for warming trend, as return wind flow becomes
established, with a gradual amplification of a short-wave
ridge over the area. The moisture return will bring slight
rain chances WED/THU days 6/7. No Arctic air or severe weather
signatures noted on the horizon at this time.

&&

.AVIATION /10Z FRIDAY THROUGH TUESDAY/...
As of 06Z...Expect mostly VFR conditions through the period.
Low pressure passing off the coast through today will move
farther away allowing any mid to high clouds to shift east, as
well. Therefore any lingering clouds around 10-12k ft will
clear through this morning with only sct lower clouds around
through the TAF period.

Extended Outlook...Possible showers along the coast Saturday
night, otherwise VFR.

&&

.MARINE...
NEAR TERM /TONIGHT/...
As of 300 AM Friday...Waves of low pressure riding up through
the off shore waters will maintain a tightened gradient flow as
high pressure extends down over the Carolinas from the north.
Winds up near 20 kts with some higher gusts will help to keep
seas up near 6 ft in the outer waters. This will maintain very
marginal SCA conditions. Seas closer to the coast will be 3 to
4 ft in a lighter northerly flow. WNA model shows the peak in
winds and seas through this morning, diminishing by this
afternoon.

SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
As of 330 AM Friday...Overall, this weekend will not be too
bad for mariners. Do not expect any pcpn. Will see a cold front
move off the mainland Carolinas late Saturday night and well
offshore Sun morning. Some clouds associated with the front but
no pcpn.

The sfc pg will tighten-some ahead of the cold front during
Sat with winds becoming westerly around 15 kt g20kt late in the
day and evening. Immediately after FROPA, winds will veer to
the NW 15 g20 kt then further veer to the North by morning at
15-20 kt. The sfc pg relaxes quickly Sun afternoon and night as
the center of high pressure approaches from the west, look for
wind speeds to drop to around 10 kt. Significant seas will
basically run 2 to 4 ft thruout this period. The seas may bump
up to a shortlived 3 to 5 ft after the CFP. After winds become
northerly and diminish to around 10 kt during Sun night, a
rather limited fetch will exist for seas to build upon under a
NW-N wind regime. This will result in seas subsiding to around 2
ft by daybreak Mon.

LONG TERM /MONDAY THROUGH TUESDAY/...
As of 228 PM Thursday...Expect a vast improvement in marine
conditions as winds ease Monday into Tuesday. As a result, a
notable easing trend in sea heights as well, with 3-4 foot seas
Sunday, slowly subsiding to 1-2 feet into Tuesday. No TSTMS
expected on the 0-20 NM waters this period.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...Small Craft Advisory until 5 PM EST this afternoon for AMZ250-
     252-254-256.

&&

$$
SYNOPSIS...DCH
NEAR TERM...RGZ
SHORT TERM...DCH
LONG TERM...MJC
AVIATION...RGZ



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