591
FXUS62 KILM 081658
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
1158 AM EST Wed Jan 8 2025

.SYNOPSIS...
All too familiar Arctic high pressure remains through late week.
Precip chances return from late Friday into Saturday. Another
chilly airmass then follows for early next week.

&&

.UPDATE...
No changes for the mid morning update. Did update climate section
below tallying our hard freezes-as all four climate sites handily
made criteria.

&&

.NEAR TERM /THROUGH TONIGHT/...
Latest surface analysis shows a stout 1041 mb high over the Great
Plains, the eastern extent of which pulls all the way over to the
Carolinas. This surface high and cold continental flow aloft keeps
us quite chilly this period. Highs only reach the low-to-mid 40s
this afternoon, albeit under plenty of sunshine.

Get ready for a cold night tonight, while a NNW breeze stiffens.
This brings the apparent temperatures (wind chills) down to 12-15
degrees, which is enough for a Cold Weather Advisory. This advisory
starts at 4 AM EST Thursday, and goes until 9 AM EST (right at the
start of the short term forecast below).

Wind chill values can lead to hypothermia with prolonged exposure.
Use caution when traveling outside. Wear appropriate layered
clothing, a hat, and gloves. Keep pets indoors as much as possible.
Make frequent checks on the elderly, family, friends, and neighbors.
Ensure portable heaters are used correctly.

&&

.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
Mid-level shortwave energy diving down the back of broad
troughing over the western Atlantic will bring a reinforcing
shot of cold, dry air on Thursday as Arctic high pressure
maintains northerly flow over the region. This will result in
temps struggling to rise through the day despite full sunshine;
most locations should manage to reach around 40F, but that`s
about it.

Although height rises will take place over Thursday night as
ridging slides eastward, the presence of very dry air and clear
skies will support another very cold night for this latitude,
with upper teens to low 20s forecast, coldest in sheltered
locations. With the high pressure center well north of our area,
some degree of a pressure gradient will remain in place and
this will result in a nocturnal LLJ that may very well prevent
open areas from decoupling and radiating to their full
potential. A Cold Weather Advisory may be necessary late
Thursday night, but if winds end up stronger, then temps won`t
drop as low and wind chills may not reach criteria. On the other
hand, if winds are calmer, actual air temps may drop to criteria
in some typically colder spots, but there may not be enough
coverage to support issuing one.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
The well-advertised storm system which will be crossing the
northern Gulf of Mexico on Friday will send plentiful moisture
overhead in the form of dense mid-upper cloud cover. Isentropic
upglide most notably found along the 295K surface overlapping
with high moisture content air will undoubtedly yield
precipitating clouds during Friday afternoon. However, the
remains of the Arctic air mass will leave a considerable wedge
of dry air beneath these clouds, which will prevent this precip
from reaching the ground and instead use it to moisten the air.
This process will also result in evaporative cooling of the
low-level air, thereby leading to a chance for light snow or
sleet to reach the ground from late Friday afternoon into the
night across northern and western areas. However, as a warm nose
becomes increasingly established ahead of the approaching
surface low, precip type concerns switch to freezing rain where
air temps manage to evaporatively cool below freezing during the
early stages of this event; even so, preceding daytime air
temps in the low 40s and rising temps through the night preclude
much concern over ice accretion, which may only be reserved to
elevated metal surfaces for a few hours where temps are cold
enough in our northern and western zones.

Otherwise, plain rain is still expected to become the dominant
precipitation type overnight as warm air both works its way down
and is advected inland at the surface ahead of the low.
Guidance continues to trend towards a faster shortwave passage,
with rain chances peaking early Saturday morning and tapering
off from west to east during the morning into the early
afternoon. QPF totals look to end up in the 0.25-0.75" range,
highest near the coast. Behind this storm system, there actually
may be some warming that occurs as clouds thin and precip
abates, leading to highs in the upper 40s inland and perhaps low
50s along/near the coast.

Beyond Saturday, cool and dry high pressure takes over for
Saturday night and Sunday, leading to chilly lows in the 20s and
daytime highs in the 40s yet again. In general, a continuation
of mostly below-normal temps can be expected as additional
troughing aloft slides through and another Arctic high builds
out of Canada early next week.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
VFR with clear skies and light winds that will become more
decidedly northerly with a weak frontal passage this evening.

Extended Outlook...Potential for MVFR/IFR Friday night into
Saturday morning as low pressure tracks near the coast. VFR
otherwise.

&&

.MARINE...
Through Tonight...NNW winds at 10-15 kts briefly back to the WNW
this afternoon before returning back from the NNW by tonight. The
gradient tightens tonight, allowing for frequent gusts up to or just
above 25 kts. A Small Craft Advisory kicks in at 1 AM EST Thursday,
going until 10 AM EST Thursday (right at the beginning of the
extended marine forecast period below). Seas at 1-3 ft increase to 2-
4 ft.

Thursday through Sunday...Aforementioned Small Craft Advisory
mentioned above expires at 10 AM EST Thursday. Winds out of the NW
still stay a bit elevated at 10-15 kts through Friday morning, but
the seas drop down from 2-4 ft to 1-2 ft again. Winds and seas
continue to decrease throughout the day Friday, and the wind
direction becomes a bit more variable. By Friday night, a
southeasterly surge builds in ahead of a cold front. The gradient
quickly tightens, allowing Small Craft Advisory conditions to return
by early Saturday morning. The cold front moves through Saturday
morning, allowing winds to progressively veer southwesterly,
westerly, and then finally northwesterly by the end of the day. At
the peak of the gradient, seas increase to 3-4 ft waves at the
coast, 6-7 ft waves 20 nm offshore. Conditions rapidly improve
Saturday night through Sunday, with NNW winds at 5-8 kts and seas 1-
2 ft.

&&

.CLIMATE...
Although our temperatures so far this winter haven`t been
excessively cold from a climatological perspective, we`ve certainly
had more cold nights this winter than we`ve seen during recent
years.

Looking at the number of hard freezes (28 degrees F or lower) since
November 2024, we`ve already exceeded the complete season totals from
the past two winters -- 2022-2023 and 2023-2024 -- in Wilmington and
North Myrtle Beach!

With the promise of more cold tonight and coming up next week, we`ll
likely approach the long-term (30 year) average number of hard freezes
along the coast with at least two more months to go before temperatures
warm for good in the spring.

   NUMBER OF NIGHTS PER WINTER 28 DEG OR COLDER (as of Jan 8)

                 AVERAGE COMPLETE   SO FAR THIS    EXPECTED TOTAL BY
    WINTER SEASON    WINTER SEASON  END OF THIS WEEK

Wilmington, NC          18              12                15
Lumberton, NC           27              13                15
N. Myrtle Beach, SC     14              11                12
Florence, SC 22 13   15

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
NC...Cold Weather Advisory from 4 AM to 9 AM EST Thursday for
     NCZ087-096-099-105>110.
SC...Cold Weather Advisory from 4 AM to 9 AM EST Thursday for
     SCZ017-024-033-054-058-059.
MARINE...Small Craft Advisory from 1 AM to 10 AM EST Thursday for
     AMZ250-252-254-256.

&&

$$

SYNOPSIS...ILM
UPDATE...ABW
NEAR TERM...IGB
SHORT TERM...ABW
LONG TERM...ABW
AVIATION...MBB
MARINE...IGB/ABW
CLIMATE...