Area Forecast Discussion
Issued by NWS Wilmington, NC

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FXUS62 KILM 290025
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
725 PM EST Wed Feb 28 2024

.SYNOPSIS...
Showers and gusty winds will accompany a cold front as it
pushes offshore late this evening. High pressure will build in
from the north Thursday, but low pressure developing just to our
south will spread clouds and rain chances back across the area
for Friday into Saturday morning. Dry high pressure should build
in for early next week.

&&

.UPDATE...
A fast-moving line of showers is whipping eastward across the
Pee Dee region now. While it should outrun the shallow
instability that is now sustaining it (and was helping it
produce severe wind gusts earlier across western South Carolina)
low level convergence appears large enough to sustain it as a
forced convective line all the way down to the coast. PoPs have
been increased to 90-100 percent for all but the SC coast (80
percent) with the window for precipitation rapidly ending after
10-11 pm as the showers move offshore.

Cool and much drier air will punch in behind the front with
dewpoints likely falling into the 20s (!) by 4 AM Thursday.
Gusty winds will tend to keep the boundary layer deep and well
mixed and I have increased forecast low temperatures by an
average of 2 degrees, trending closer to the raw models and away
from the NBM MOS.

&&

.NEAR TERM /THROUGH THURSDAY/...
A very warm and windy day for late February will come to a
characteristic end as a sharp cold front sweeps through this
evening, bringing a band of gusty showers, a sharp wind shift to
northwest, and strong cold advection behind it. Although instability
will be lacking, wind gusts up to 50 kts may mix down in the
strongest band of showers, which should cross into Darlington and
Marlboro counties around 23 UTC and generally weaken with time as
they continue steadily southeastward and reach the coast around 03
UTC. The Storm Prediction Center has highlighted Marlboro,
northwestern Darlington, and northwestern Robeson counties in a
Marginal risk (level 1 of 5) for severe wind gusts up to 50 kts as
these showers move in. Peak gusts may reach 35-40 kts between the
coastal counties and I-95, but overall organization will be on the
decline, resulting in an increasingly broken line of showers with
decreasing intensity.

Behind the cold front, initially northwesterly winds will become
more northerly as much cooler and drier air spills in. While low-
and mid-level clouds will scour out during the night due to the dry
advection, high-level moisture will persist as subtropical jet
cirrus continue to stream overhead through Thursday. Closer to the
ground, extremely dry air combined with subsidence at the top of the
boundary layer will bring dewpoints into the low 20s and perhaps
even the teens. After morning lows in the 30s to around 40, temps
should rebound into the middle 50s, bringing RHs down into the 20s
during the afternoon.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
High pressure will migrate off of the Delmarva coast by Fri
morning. The high will continue to extend down into the inland
Carolinas while a coastal trough develops. The low level flow
will be from the E to NE as shortwave aloft approaches from the
west with SW to W flow in the mid to upper levels. This should
help deepen the coastal trough into a low right along the
Carolina coast before tracking off to the NE and deepening into
Sat.

Initially, moisture will work its way down with clouds increasing
and thickening Thurs night with increasing lift into Fri.
Expect the best pcp with isentropic lift inland and enhanced by
moist onshore flow and coastal trough along the coast. Overall,
expect increasing and thickening clouds Thurs night with pcp
chances increasing into Fri. Some areas could see periods of
heavier rain. The coastal trough will push inland some on Fri,
but shortwave and low will lift it off to the NE Fri night with
some drier air wrapping around into the area into Sat. May see
some lingering pcp and may take a while to clear, especially
along the coast as another wave of low pressure tracks along
boundary near or just off the coast through Sat night.

Temps on Thurs night will be down near 40 but will modify a good
10 degrees by Fri night with 50s for lows most of the rest of
the weekend into early next week. Daytime highs should warm
closer to the coast as trough pushes inland a bit with readings
up around 60 but inland should remain in the 50s in cooler wedge
of high pressure. Rest of the period should see temps up near 70
or above most places.

High pressure will build in on the back end late Sun through
early next week with dry weather expected until another system
makes its way up from the Gulf coast into midweek.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Low pressure exiting the region by early Saturday will reinstate
SW flow and ridging aloft. Drier air will begin to filter in
behind the low at some point during the day. Ensemble spread
indicates that the center of the low may be slow to leave the
area, hence prolonged showers chances into Saturday night and
delayed arrival of dry air. Lee side of the low should at least
bring slightly warmer temperatures with highs in the 60s.

The existing low off of the northeastern US coast will maintain
a surface boundary offshore on Sunday. Guidance continues to
suggest temperatures will rebound into the low or mid 70s, but
confidence remains low. Moisture beneath an inversion and
easterly flow within the boundary layer will work against these
warm temperatures. Have opted to undercut highs by a couple of
degrees. Surface convergence near the coast will extend the
chance of showers into Sunday afternoon as easterly winds bring
developing showers close to our coastal communities.

Remaining uncertain early next week as weak high pressure builds
into the area. Sunshine with inconsistent cloud cover should at
least bring warm temperatures. Highs each day in the upper 60s or
low 70s. A better chance of unsettled weather later in the week.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
A fast line of showers will whip through the KLBT and KFLO
airports between now and 0130 UTC with moderate to heavy rain
and gusty winds. Short lived MVFR to perhaps IFR conditions may
occur in this convection. Activity should diminish in intensity
and organization as it approaches the coastal airports later
toward 0230 to 0330 UTC but should still bring a burst of heavy
rain and gusty winds. Synoptic winds should shift northerly
between 0400 to 0600 UTC with much drier air bringing VFR
conditions through Thursday.

Extended Outlook...There is a high potential for MVFR ceilings
and visibilities from rainfall and fog Friday afternoon into
Saturday morning as coastal low pressure lifts across the
eastern Carolinas. There is also a moderate potential that
conditions could slip into the IFR category, mainly from low
cloud ceilings during this time.

&&

.MARINE...
Through Thursday...SCA-level winds and seas will dominate tonight
into tomorrow as a tightened pressure gradient remains in place.
Seas peak in the 5-8 ft range this evening with the cold frontal
passage progged for 03-05Z. As high pressure builds in, northerly
flow will take over after midnight with SCA conditions expected to
abate by late morning on Thursday. Seas continue falling to around 2-
4 ft Thursday afternoon while winds relax into the 10-15 kt
range.

Thursday night through Monday...Winds and seas will continue to
diminish Thurs night into Fri with sub-SCA conditions under
high pressure. High pressure will shift off the Delmarva coast
Thurs night into Fri with onshore winds developing and
increasing as coastal trough develops. Therefore, seas will drop
down to 2 to 4 ft but will increase again through Fri up to 3
to 5 ft and should reach up to 4 to 6 ft Fri night through Sat
in onshore easterly flow up to 20 kts.

The coastal trough will deepen into low late Fri into Sat
before lifting off to the NE with weakening offshore flow
through the latter half of the weekend. Winds and seas will
weaken leaving a light NE flow Sun into Mon with seas down to 3
to 4 ft most waters.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...Small Craft Advisory until 11 AM EST Thursday for AMZ250-252-
     254-256.

&&

$$

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


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