Area NWS Forecast Discussion
445
FXUS62 KILM 180101
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
801 PM EST Fri Jan 17 2020

.SYNOPSIS...
High pressure will slip offshore late tonight, allowing for a
brief weekend warmup prior to the next cold frontal passage Sun
morning. Scattered showers will occur ahead of the front from
late Sat afternoon up until it`s passage Sunday morning. Much
colder temperatures will follow during the upcoming work-week
as air, of Arctic origin, dips into the Carolinas.

&&

.UPDATE...
Public:
Latest fcst looking aok. No major changes needed or expected.
Will however tweak a few elements based on latest observations
and resulting trends, but again no categorical changes needed.

Marine:

Latest winds and seas across the ILM NC Waters have dropped
below SCA thresholds and as a result the SCA has been allowed to
expire at 6 pm. This overall diminishing and subsiding trend
will continue, with the ILM SC Waters still progged to fall
below SCA thresholds by Midnight tonight. The elongated center
of sfc high pressure will drop into the Carolinas tonight,
resulting in the sfc pg relaxing-some. Significant seas will
peak early this evening followed by a subsiding trend due to the
reduction and size of the short period wind-driven waves. An
underlying 2 to 3 foot Easterly swell at 9 to 11 second periods
will persist overnight into Sat.

&&

.NEAR TERM /THROUGH SATURDAY NIGHT/...
Dry wx continues through tonight with strong sfc high pressure
centered just NE of the local area. With diminishing winds,
temps will bottom out in the low/mid 30s most areas, except upr
20s in the normally coldest spots. As the high slides eastwards,
the NE flow tonight will transition to SE on Sat allowing for
warmers temps and dewpoints than today...highs in the 50s to
near 60. After a dry morning, rain chances will increase a bit
through the day as moisture increases ahead of an approaching
cold front. Not much in the way of forcing during the daytime
period, so PoPs are capped in the 20-40% range, highest near the
coast where low-level convergence will be greatest. Better
chance for rain arrives after midnight Sat night (50-60% PoPs
everywhere) with the fropa, but not expecting heavy pcpn.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
Majority of the rain will be offshore by Sunday morning, with a
few lingering light showers possible. Cold front moves through
Sunday morning with winds shifting to the NW and dewpoints
dropping fast throughout the day. Cold advection, however, lags
behind and doesn`t really set in until Sunday night, allowing
temps Sunday to rise to low 60s under clearing skies. Temps drop
fast to around 30 degrees Sunday night as surface high pressure
builds in over Central US. Temps around 10 degrees below normal
Monday and Monday night due to strong cold advection of arctic
air, with highs in the mid 40s and lows in the mid 20s.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
Tuesday and Tuesday night is setting up to be one of the
coldest days so far this season, with highs in the low 40s and
lows around 25 degrees. A strong upper level trough digs down
across the SE US Tuesday into Tuesday night, that may lead to
some clouds and a possible flurry or two. Will be pretty tough
though given very dry air in place at the time. The European
model has a low pressure system develop off the east coast
Wednesday through Thursday keeping precip close to our coast,
but favoring a more dry forecast for now. Air mass will begin to
modify Wed night into Thurs as ridge builds over the Southeast
and surface high shifts slowly eastward. Overall, will see a
rebound toward normal or above normal temps Thurs into Fri, with
any rain holding off until possibly this weekend.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
VFR conditions expected thruout the 24 hr TAF Issuance period.
Thin to occasionally opaque cirrus expected thru the night,
with some increase in a mid-level cloud deck during Sat
afternoon. Expect some onshore movement of stratocu across the
SC portions of the ILM CWA, affecting MYR and CRE terminals with
3k-4k foot ceilings. The threat for steady and measurable pcpn
will hold off for the most part until after 05z Sun. Winds
generally NE-ENE around 5 kt tonight, veering slowly to E-SE
early Sat aftn and S to SW immediately ahead of the approaching
cold front.

Extended Outlook...Mainly VFR thru the period except for
possible showers ahead of a CFP . Showers possible Saturday
night into early Sunday, could briefly lower ceilings and vsby
to MVFR early Sunday.

&&

.MARINE...
A Small Craft Advisory continues through this evening, with
gusts to 25 kt and 6 ft seas continuing out 10-20 nm. Improving
marine conditions then for late tonight and Sat as sfc high pres
retreats to the E and CAA ends. Winds and seas then ramp up
again Sat night ahead of the next cold front, with another round
of Small Craft Advisory conditions expected by the evening
hours, with SW winds gusting to 25 kt and seas again up to ~6
ft. Dominant periods in the 5-6 second range.

Small Craft conditions likely continue through at least Sunday
afternoon. SW winds early Sunday around 20 kts become NW by the
evening around 15 kts, with seas 5-7 ft slowly decreasing to 3-5
ft by Sunday night, a 7 sec SW swell. High pressure builds over
central US Sunday night, setting up northerly winds across our
area Mon- Thurs. Some guidance hinting at a development of an
offshore low late Tues into Wed that would lead to winds
increasing to possible SCA criteria, but confidence low. Winds
veer to northeasterly Thursday and then easterly on Friday as
the aforementioned surface high shifts north of our area and
then further offshore to the northeast allowing return flow to
develop. Seas 2-4 ft Monday through Friday, with occasional 5
footers late Tuesday and again on Thursday, predominantly 5-6
sec NE wind wave.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...Small Craft Advisory until midnight EST tonight for AMZ254-256.

&&

$$
SYNOPSIS...DCH
UPDATE...DCH
NEAR TERM...MAS
SHORT TERM...VAO
LONG TERM...VAO
AVIATION...DCH
MARINE...DCH/MAS/VAO

NWS ILM Office Area Forecast Discussion