Area Forecast Discussion
Issued by NWS Wilmington, NC

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FXUS62 KILM 231050
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
550 AM EST Fri Feb 23 2018

.SYNOPSIS...
A cold front dropping south through North Carolina will remain
north of the local area as high pressure holds over the area.
Bermuda High will continue to bring unseasonable warm weather
through the weekend. A cold front will arrive on Monday bringing
a chance of rain, and temperatures closer to normal early next
week. A warming trend is expected next Wednesday and Thursday,
as a low pressure system approaches from the west.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 300 AM Friday...For our area, basically persistence
forecast will continue with early morning areas of fog and sea
fog lifting by mid morning, but a few differences will be seen
today which should lead to a slight increase in shwr potential.
Have issued a Special Weather Statement for patchy dense fog
through the early morning hours.

A blanket of stratus was creeping south associated with a
backdoor cold front pushing its way south into North Carolina
early this morning. This front will get pushed back north before
reaching our local forecast area as southerly winds increase
through this morning. Therefore, may see some strato cu reaching
this far south but for now do not expect this blanket of low
clouds to reach into our area. The front to the north should
disrupt the winds a bit giving a slightly more E to SE
direction along the coast as front pushes into NC this morning,
but overall southerly flow will dominate heading into later
today and tonight.

Some of this cooler air from the north reaches down in the low
levels with 850 temps dropping from near 16C down to 9 to 10C
through today. The ridge will also shift slowly south. This
will help steepen the low level lapse rate, and the subsidence
inversion lifts up to around 6 to 7k ft with a slightly deeper
convective potential, although still expect it to be suppressed
for the most part. Will include isolated shwrs in spots this
aftn and overnight, especially over the waters later tonight
into tomorrow morning. Moisture profiles show this growth of
moisture later today and tonight. The southerly winds increase
into tonight and may be enough to drive some of the showers from
nearby waters onto the coast and also may keep fog limited to
inland areas and more in the way of marine stratus over coastal
areas. But with this shallow warm and moist air continuing, will
include fog and sea fog over a good portion of the area
tonight.

Although some of the cooler air may try to bleed down into the
area, expect the ridge and warm and moist southerly flow to win
out with temps reaching near 80 once again for most places. This
will threaten the records which include 80 for Wilmington in
1975, 74 for North Myrtle in 2017, 83 for Florence in 1975 and
78 for Lumberton in 1971. Highs at the beaches will be about 10
degrees cooler. Overnight lows tonight will be between 55 and 60
most places.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
As of 330 AM Friday...All good things must come to an end...and in
this case, the end of early summer in February beginning late
this period.

Upper ridge will slowly flatten out this period due to successive
mid-level short-waves passing just west and north of the FA. The
ejection of the Desert SW upper trof will finally be the kicker for
finally pushing the stalled sfc bndry across the mid-section of the
U.S. as a cold front. This boundary will reach the FA late Sunday
and likely slow down or even temporarily stall as it becomes aligned
parallel with the upper flow.  As for both days this weekend, still
looking at widespread 80 degree temps except cooler along the
immediate coast. As for POPs, have indicated 20 POPs for Sat mainly
in the form of isolated showers. Brief POP reprieve Sat night
followed by increasing POPs Sun thru Sun night. Will see high chance
POPs bordering likely late Sun night. Have kept thunder at bay but
this will need some monitoring.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
As of 330 PM Thursday...A front will be stalled in the area
Mon. A series of shortwaves, emerging from the base of the 5h
trough over the Southwest, move along the stalled boundary. Deep
southwest flow helps spread moisture over the southeast while
the waves aid dynamics. Anticipate an increase in precipitation
in the area as the waves move overhead. Confidence on timing is
on the low side as there is still some disagreement between the
GFS/ECMWF solutions, but the slower ECMWF might be the way to go
given the presence of a mid-level ridge. Cloud cover and precip
will keep temperatures cooler than previous days but both highs
and lows will remain above climo.

Surface high builds over the southeast Tue into Wed as flow aloft
becomes progressive at the top of a 5h ridge over the Gulf of
Mexico. Quiet period is short lived as the flat 5h flow moves the
remains of a stalled front into the area, which is then lifted north
as a warm front Wed into Thu. Subtle amplification of the mid-level
pattern late in the period will push above normal temps during the
midweek period to well above normal for the end of the period with
potential for convection late Thu or Thu night as a cold front moves
into or across the area.

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
As of 12Z...Another foggy morning. A back door cold front resides
north of the CWA, and will likely remain there. The fog should bake
off by 14-15Z, with continued southerly flow. Look for cumulus to
form around 16Z, with isolated showers possible. Have not introduced
fog as of yet for Saturday morning, but will take a good look on the
next set of TAFs.

Extended Outlook...Morning IFR/BR possible through Sat, otherwise
VFR. SHRA/MVFR Sunday through Monday, becoming VFR Tues.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
As of 300 AM Friday...A cold front dropping down through the NC
waters will hold to the north of the local waters but will act
to shift winds to a more SE direction today. Overall will
maintain a light S-SE flow over the waters and seas around 3 ft
over most of the waters. Fog over the waters this morning will
once again develop overnight tonight, with locally dense spots
reducing visibilities. A Marine Weather Statement was issued for
patches of dense sea fog.

Winds will have a slight increase and turn more SSW direction
overnight tonight but still remaining around 10 kts or so. Seas
will remain less than 4 ft.

SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
As of 345 AM Friday...Sfc ridge axis from the Bermuda high will
drop south of the FA with time. This will lead to wind
directions veering from South to Southwest. Wind speeds
initially will be 10 kt or less Sat, then increase to 15 to 20
kt from Sunday thru Sun night as the sfc pg tightens ahead of
the approaching cold front. A southwesterly 25 to 35 kt low
level jet will keep the boundary layer mixed late Sat night into
Sun and the SW wind direction will limit the fetch for sea fog
development across the local waters. Significant seas will
basically be governed by an ESE to SE ground swell at 9 second
periods. The increase in short period wind waves during Sun will
push seas to 3 to 5 ft which leads to the good possibility of a
SCEC needed for Sun into Sun night. Obviously, too early to
raise it but will mention in the Hazardous Wx Outlook.

LONG TERM /MONDAY THROUGH TUESDAY/...
As of 330 PM Thursday...Winds north to northwest Mon morning
behind cold front. Surface high builds in from the west Mon into
Tue, then shifts overhead Tue afternoon. Northeast surge Mon
night will peak around 20 kt close to midnight but then the
gradient starts to weaken as the high moves closer. Northeast
flow starts to wind down after sunrise Tue with winds slowly
veering to easterly and dropping to 10 kt or less as the period
ends. Seas drop to 2 to 4 ft Mon. Northeast surge Mon night into
Tue will push seas back to 3 to 5 ft for much of Tue before
decreasing winds allow seas to fall to 2 to 3 ft Tue night.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...None.

&&

$$

SYNOPSIS...RGZ
NEAR TERM...RGZ
SHORT TERM...DCH
LONG TERM...III
AVIATION...43



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