Area Forecast Discussion
Issued by NWS Wilmington, NC-- Remove Highlighting --
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FXUS62 KILM 081148
Area Forecast Discussion
National Weather Service Wilmington NC
648 AM EST Thu Dec 8 2016
High pressure will bring a dry and seasonable day today. A cold
front will move through later on Thursday, ushering in the
coldest temperatures of the season for the first part of the
weekend. A warming trend will follow Sunday into Monday ahead of
the next cold front. Expect seasonable and dry weather Tuesday
as high pressure builds in behind front. Another frontal system
will affect the area during the middle of next week.
.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --As of 630 AM Thursday...Areas of stratus and stratocu will
plague the region this morning. Latest mosaic 88D shows virga
across central NC. Sfc obs underneath did not report any pcpn.
As a result, will continue with the dry fcst and CFP.
Drier air aloft later this morning with the days insolation
should help break down a portion of the low stratus. However,
clouds ahead of the approaching cold front will fill back in as
it approaches the FA from the northwest later this morning and
afternoon. Only minimal convergence along the front which is
likely not enough for pcpn development. In fact, with westerly
flow aloft, moisture accompanying this front will scour-some as
it progresses to and across the FA this aftn. Looking at mid-
late aftn when the cold front clears the ILM CWA Coast. The sfc
pg will tighten after the CFP resulting in NW winds increasing.
the cold surge lags slightly behind the front and will really
begin to be realized during the pre-dawn Fri hours. Post frontal
clouds will affect the FA overnight, with the drier air thru
the atm column occurring during Friday, after the mid-level trof
axis pushes thru. Used the hier max temps from the avbl model
mos guidance and also stayed on the hier side for tonights mins
which will occur around or after daybreak due to CAA
infiltrating the FA.
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.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
As of 400 AM Thursday...Modified Arctic air and dry conditions
will govern this period.
Progressive flow at all levels this period will prevent the
modified Arctic high pressure from affecting the FA from more
than 2 days. The High itself will ridge across the FA during
Friday, with it`s center pushing across NC Saturday and off the
Mid-Atlantic coast by Sun morning. Will have 3 mornings with low
temps at or below the freezing mark, with Saturday morning
being the coldest with widespread 20s. Enough of a wind Friday
night into early Sat morning will result in wind chill readings
in the upper teens to around 20. Skies thru this period will be
mainly clear except for Sunday morning when models indicate a
weak inverted sfc trof off the Carolina coasts with possible
stratocu moving to the coast. If cloudiness and weak onshore
flow becomes more prevalent Sun morning, min temps along the
coastal counties may actually rise above 32 during the pre-dawn
Sun hrs given various thickness fields also increasing.
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 3 AM Thursday...Boundary and surface temperatures progged to
recover some 10-12 degrees F on Sunday as the wedge weakens beneath
strong low level warm advection. Increased cloud cover resulting
from the upglide will temper the warmth slightly but Monday will
benefit from a much warmer start and should actually turn out warmer
than climatology. Rain chances associated with coastal trough Sunday
into Sunday night will continued to be carried but capped low as
they are likely a case of over aggressive moistening by guidance, a
seemingly common error. Rain chances should max out Monday as a cold
front moves through, though the lack of deep layer veering should
keep QPF prospects minimized as it prevents the mid levels from
moistening. After a dry and fairly seasonable Tuesday we may be
looking at another Arctic cold front on Wednesday.
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
As of 06z...A weak frontal wave is approaching from the northwest.
Ahead of this system a fairly solid deck of MVFR ceilings have
developed. This moisture was very poorly initialized by model
guidance, lowering the forecast confidence regarding its tenacity.
Normally the best course is to keep lowered conditions as-is until
daybreak especially this time of year. There is some wind above the
surface layer so any VSBY restrictions likely fairly transient and
only MVFR. VFR after sunrise with just a windshift to the NNW
spreading south across the terminals this evening as the Arctic
front pushes through.
-- Changed Discussion --NEAR TERM /THROUGH TONIGHT/...
As of 630 AM Thursday...SCA raised for this evening through
late Friday afternoon.
Benign conditions this morning will give way to an increase in
wsw-w winds around 10 kt ahead of the approaching cold front.
Look for the CFP during late this aftn, to well offshore during
this evening. The sfc pg tightens quickly after the CFP with NW
winds increasing to 10 to 20 kt by sunset. The cold surge will
lag behind the cold front but should be in full force across the
area waters during the pre-dawn Fri hrs. Winds will further
increase to 15 to 25 kt with added gustiness to 30 kt, especially
across the warmer outer waters and closer to the Gulf Stream or
any eddies having broken off from the Stream. Significant seas
will run 1 to 2 ft this morning, building to 2 to 4 ft late this
afternoon. Further building to 3 to 5 ft, up to 6 ft 20 nm out
of the Capes late. Weak Pseudo swell from the south at 7 second
periods will dominate this morning, then give way to building
wind driven waves at 3 to 5 second periods tonight.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
As of 400 AM Thursday...SCA conditions expected for daytime
Modified Arctic air will advect across the local waters during
friday and when combined with a tightened sfc pg, expect winds
to be from the NNW-NNE at 15 to 25 kt with possible gusts up to
30+ kt during the peak of the CAA during Fri morning. The center
of the modified Arctic high will move across NC during Sat and
progress off the Mid-Atlantic coast Sat night. Will only see N
to NNE winds drop off Fri night thru Sat to 10 to 20 kt, with
the lower speeds across the ILM NC waters due to the proximity
of the high`s center. Could see more of a NE wind direction
thruout the waters by Sun morning if the inverted sfc trof just
offshore and parallel to the coasts becomes a reality. The sfc
pg will slightly tighten after the high`s center bypasses the FA
late Sat night which could push winds back to 10 to 15 kt or
around 15 kt. Significant seas will peak early to midday Friday
followed by just a slow subsiding trend. This a result of seas
being dominated by locally produced wind driven waves at 3 to 5
second periods. The offshore nature of the winds early on this
period, will produce a range of seas when they peak, ie. 1 to 3
ft at 0 to 10 nm out, and 3 to 6 ft at 10 to 20 nm out. The 6
footers to occur outer waters off Cape Fear and Romain
LONG TERM /SUNDAY THROUGH MONDAY/...
As OF 3 AM Thursday...Winds initially out of the SE on Sunday
with a weak coastal trough in place. Late in the day into Sunday
night this feature washes out and a SSW flow gets established
and strengthens some. A few 5 ft seas may materialize well away
from shore but the coast-parallel fetch may preclude headlines
since most of the area sees smaller waves. Monday`s forecast
rather uncertain as models are in poor agreement in timing the
next front. The slower and slightly favored solutions would
allow for a moderately strong prefrontal SW flow that would
likely require an advisory.
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MARINE...Small Craft Advisory from 9 PM this evening to 6 PM EST Friday