481
FXUS62 KILM 050005
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
705 PM EST Wed Dec 4 2024

.SYNOPSIS...
Breezy west to southwest winds will develop late tonight into
Thursday ahead of a dry cold front that should move offshore late
Thursday. Another period of cold weather will develop Thursday
night through the weekend as Canadian high pressure moves across
the area. South winds from Florida and the Gulf of Mexico will
bring clouds, rain chances, and milder temperatures next week.

&&

.UPDATE...
A couple updates have been made to the forecast based on
current observations and the 18z GFS and NAM:

- Forecast lows tonight have been adjusted downward by a few
  degrees away from the beaches as good radiational cooling is
  occurring now. The developing nocturnal inversion is going to
  be fragile and should be almost completely mixed out by
  increasing boundary layer winds overnight. Forecast hourly
  temperature curves have been hand-edited to show an increasing
  trend after late evening lows have occurred.

- The strong low level jet should mix down to the surface
  Thursday morning after sunrise. This could bring 40 mph wind
  gusts to the surface across the coastal counties with some
  tricky travel possible for high profile vehicles. Across
  Lumberton and the Pee Dee region it`s possible 35 mph gusts
  could develop before sunrise if turbulence can transport gusts
  down without diurnal destabilization of the boundary layer.
  Forecast winds have been adjusted higher during this time.

&&

.NEAR TERM /THROUGH THURSDAY/...
Southwest winds are on the rise this afternoon as the center of high
pressure sits to our south. The pressure gradient will continue to
increase tonight as a cold front pushes towards the area and high
pressure moves offshore. Winds could become light after sundown, but
they`ll pick back up by midnight and stay breezy through dawn, gusts
near 25-30 mph. This will serve to moderate low temperatures some,
where we could see lowest temps early in the night with the calmer
winds, and then more steady temps towards sunrise. Raised lows
slightly from guidance due to the overnight breeze with lows in the
upper 30s near 40 at the coast. Once the sun comes up and we start
mixing stronger winds down, gusts Thursday morning could reach near
30-40 mph until the LLJ lifts and the cold front pushes through. The
front will move through in the late afternoon with winds remaining
breezy through the evening, but lower gusts than the morning. The
frontal passage will remain dry but some moisture with it could
increase cloud cover with and ahead of it. Highs near 60.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
Behind a strong cold front, breezy north-northwest winds will
bring steady cold air advection through Thursday night. This
is expected to bring dew points down to around 10F and low temps
into the low 20s and wind chills into the teens. With mid-level
troughing remaining overhead and a robust shortwave rounding
its base during the day on Friday, expect chilly high temps
generally in the middle 40s while north-northwesterly winds
continue around high pressure centered over the mid-South. This
high pressure center will gradually make it ways towards the
coast over the weekend, with light or calm winds expected for
Friday night. The combination of clear skies, very dry air, and
light or calm winds will support another very cold night with
good radiational cooling causing lows to dip into the upper
teens to low 20s away from the immediate coast. On Saturday, it
appears the high pressure center will remain to the west but
with a very weak pressure gradient in place, winds will be light
and variable during the day. High temps will recover some as the
airmass modifies, but highs will struggle to reach 50F beneath a
strong subsidence inversion.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
Surface high pressure is expected to cross the coastline late on
Saturday night or during the morning on Sunday, resulting in
southwesterly low-level flow taking over for the remainder of
the weekend. This, in tandem with a shortwave ridge causing
rapidly rising 500mb heights, will yield a sharp warmup with
highs expected to reach around 60F on Sunday after morning lows
in the mid-upper 20s.

Beyond Sunday, confidence decreases as the southern stream becomes
more active. A closed low over the desert southwest/northwest
Mexico is expected to open up into a shortwave and dampen as a
broader trough dives into the western US behind it. This wave
will pick up at least some Gulf moisture as it tracks across the
lower Mississippi Valley and into the Ohio Valley, but most of
this may end up raining out west of our region as the wave lifts
away well to our northwest. Nevertheless, plenty of mid-upper
moisture will likely lead mostly cloudy conditions from Sunday
night onward and ridging ahead of this wave will lead to warming
temperatures. The aforementioned broader trough is progged to
feature a sharpening shortwave which may lead to a considerable
rain-maker around midweek, but specific details are murky at
this time. Temperatures are likely to reach above-normal during
the first half of the new week with highs potentially reaching the
low 70s before the next cold front arrives just beyond the end
of the period. Lows should warm into the 50s amidst rising dew
points ahead of the next cold front.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
The biggest weather concerns will be low level wind shear
tonight followed by strong west-southwest surface winds after
sunrise Thursday. A low level jet is developing now across the
eastern Carolinas and should increase to 35-40 knots at 1200
feet AGL over the next few hours. Winds at 2000 feet AGL will
increase to 45 knots after 06-08z Thursday. Surface winds will
gradually increase through the night beneath the core of the jet
aloft. The strong winds aloft will mix down to the surface at
sunrise Thursday with gusts at the surface expected to reach
34-37 knots at all local airports.

Aside from some mid level clouds streaking across South Carolina
tonight and some scattered cumulus developing during the day
Thursday, VFR conditions will continue over the next 24 hours.

Extended Outlook...VFR.

&&

.MARINE...
Through Thursday...High pressure will slip offshore to our south as
the pressure gradient increases ahead of a strong cold front. Winds
and seas will increase tonight, meeting Small Craft Advisory
criteria. Winds will increase further during Thursday as the front
approaches and moves through in the afternoon, gusts reaching Gale
Force by the early morning with seas 4-7 ft. The front will move
offshore later in the day with winds and seas decreasing, but they
may still need a Small Craft Advisory through the end of the
period.

Thursday night through Monday...
North-northwesterly flow will persist through Saturday as high
pressure slowly tracks eastward towards the coast. On Thursday
night, speeds around 20 kts with gusts hovering around Small
Craft Advisory criteria in the 25-26 kt range are expected
during the first half of the night, with speeds gradually
decreasing after midnight. Seas initially around 3-5 ft early in
the night also decrease gradually after midnight. Winds and seas
decrease further on Friday as the gradient slackens and
eventually fall to more benign levels below 10 kts and around
1-2 ft on Saturday as the high draws nearer to the coast. The
center of the high should pass over the waters on Sunday morning
with winds backing to southwesterly and remaining 10 kts or
less. As the high moves increasingly offshore on Monday ahead of
a cold front, winds back to southerly and increase somewhat,
leading to seas creeping back up through the end of the period.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
NC...None.
SC...None.
MARINE...Small Craft Advisory until 4 AM EST Thursday for AMZ250-252-
     254-256.
     Gale Warning from 4 AM to 3 PM EST Thursday for AMZ250-252-254-
     256.

&&

$$

SYNOPSIS...ILM
UPDATE...TRA
NEAR TERM...LEW
SHORT TERM...ABW
LONG TERM...ABW
AVIATION...TRA
MARINE...LEW/ABW