092
FXUS62 KILM 201113
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
613 AM EST Mon Jan 20 2025

.SYNOPSIS...
Arctic high pressure will bring very chilly weather through
midweek. A chance of snow will come late Tuesday through early
Wednesday. Another round of wintry weather may affect the
Coastal Carolinas Thursday. Friday and the weekend will be
rain-free and feature a gradual warmup towards more normal
temperatures.

&&

.UPDATE...
Small Craft Advisory expired at 6a. Forecast remains on track
for a chilly day. Aviation discussion updated for the 12z TAFs.

&&

.NEAR TERM /THROUGH TONIGHT/...
Arctic high pressure will build in behind departing cold front
through tonight. Stiff northerly winds will usher in plenty of cold
and dry air. Temperatures down just below freezing this morning will
struggle to get to 40 this afternoon and combined with the northerly
winds, much of the day will feel like low to mid 30s. This will be a
good 15 degrees below normal.

Heading into tonight, low temps will drop into the teens, and
combined with the northerly winds, wind chill values will be down
into the lower teens. Therefore a Cold Weather Advisory has been
issued for late this evening into early Tues morning. It will be
very dry through tonight with no clouds and no pcp. Dewpoint temps
will drop out into the single digits and down near 0 in spots inland.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
Confidence remains low for Tue and Tue night. Feeling fairly
confident that the forecast area will experience some winter
precipitation, in the form of snow, but the exact details remain
clouded in mystery. The problem continues to be the strength/dryness
of the surface high and the relatively narrow band of deep moisture
along or just off the coast. There is no real surface low to hang
one`s hat on. Instead a loose band of weak shortwaves will be left
to do the heavy lifting. Forecast soundings suggest the air mass is
far too dry during the time of best isentropic lift. By the time the
moisture moving in from the Gulf arrives the strongest isentropic
lift has shifted offshore leaving limited forcing and an abundance
of moisture over the area.

Moisture profiles alone support some precipitation falling from the
clouds, but hardly suggest anything robust. It may be a struggle to
get 1" across much of the region. Bulk of the 00Z guidance has come
in a little lower than with qpf/snow amounts, supporting lower total
accumulations. After discussions with neighbors and WPC have decided
to delay watch issuance given the lack of confidence and the fact
that the forecast falls around an inch short of 2" within the
forecast area. A better strategy may be to deploy a Winter Weather
Advisory later today, once the window for that product opens.

Cold and dry high pressure settles over the region following the
excitement Tue night. Skies start out cloudy, mainly mid and high
cloud, but do clear out during the day. Even with sun in the
afternoon temperatures will struggle to reach the freezing mark. In
fact if a little more snow falls than expected, it`s possible highs
Wed could end up below freezing. There are some suggestions that
light precipitation could begin during the predawn hours Thu morning
along the coast. However, lift is quite weak and there is a lot of
dry air. Given the unfavorable environment have no plans to carry
any mention of precipitation prior to 12Z Thu.

The combination of winds and temperatures Tue and Wed nights will
likely require a Cold Weather Advisory for at least a portion of the
forecast area if not the entire area.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
Later portion of the week starts out interesting with an air mass
some 15 degrees or so below normal in place under broad mid-level
troughing. Weak wave develops along a trough/frontal remnants
lingering just off the southeast coast early Thu. This wave/low
could be close enough to spread some light precipitation over at
least eastern portions of the forecast area as it moves northeast
later Thu and Thu night. The result could be a period of light
freezing rain/drizzle at some point later Thu or Thu evening.
Confidence is low and there is disagreement on when and where the
wave develops, in other words the theme of the week - wait and see -
continues.

Remainder of the long term is pretty straight forward. Below climo
temperatures continue through Sat night. A 5h trough axis swings
through Fri night into Sat, but lacks any deep moisture so no
precipitation concerns. High pressure builds in from the west Sat,
shifting off the coast early Sun with warm advection pushing
temperatures near to above climo for the start of next week.

&&

.AVIATION /12Z MONDAY THROUGH FRIDAY/...
VFR conditions are expected through the valid TAF period as
Arctic high pressure builds in. Northerly winds will persist
through the period mainly around 10 kt with some higher gusts.
Skies will remain clear through most of the period with some mid
to high clouds increasing between 06z and 12z Tues.

Extended Outlook...Next chance for flight restrictions comes
late Tuesday into Wednesday, where a Gulf low likely brings
a bit of snow to the area. Back to VFR Wednesday afternoon.
Another system could cause flight restrictions on Thursday into
Friday.

&&

.MARINE...
Through Tonight...
Arctic high pressure will build over the waters through
tonight. Strong gusty northerly winds will diminish through this
morning ending Small Craft Advisory conditions. Northerly winds
up to 20 kts this morning will continue to remain gusty but in
the 10 to 15 kt range with gusts up to 20 kts this afternoon
through tonight. Seas 3 to 5 ft will subside to 2 to 3 ft by
tonight but will begin to rise again slowly into Tues.

Tuesday through Friday...
A couple weak systems will affect the waters this week, but the
big concern will be the pinched gradient later Tue through Wed
as high pressure builds in and weak waves of low pressure pass
off the coast. Winds and seas will likely require a Small Craft
Advisory later Tue into Wed afternoon. Surface high retreats
north Thu and Fri with the gradient weakening and speeds
dropping under 15 kt. Winds become more northwest Fri after weak
low passes offshore, but speeds will remain 15 kt or less.
Other than 6 ft seas Tue/Wed seas will run 2-4 ft with a
northerly wind wave being dominant over a weak east to southeast
swell.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
NC...Cold Weather Advisory from 10 PM this evening to 10 AM EST
     Tuesday for NCZ087-096-099-105>110.
SC...Cold Weather Advisory from 10 PM this evening to 10 AM EST
     Tuesday for SCZ017-023-024-032-033-039-054>056-058-059.
MARINE...None.

&&

$$

SYNOPSIS...ILM
UPDATE...RGZ
NEAR TERM...RGZ
SHORT TERM...III
LONG TERM...III
AVIATION...RGZ
MARINE...III/RGZ