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390
FXUS62 KILM 171402
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
1000 AM EDT Tue Sep 17 2024

.SYNOPSIS...
Drier air will slowly build in especially during Tuesday. Warm
conditions with daily low chances for showers and thunderstorms
are expected through midweek. A weak cold front will bring more
seasonable temperatures near the end of the work week.

&&
.UPDATE/...
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No changes to the forecast at this time.
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&&

.NEAR TERM /THROUGH TONIGHT/...
Deep dry air continues to wrap around the low, which has now wobbled
its way to near Charlotte. The deep dry air will remain in place
with forecast soundings showing an inversion around 2k ft this
morning that increases to 4k ft later in the afternoon. Low level
moisture trapped below this inversion will keep skies cloudy through
mid-morning before coastal areas start to break out. Inland areas
may not see some breaks start to appear in the clouds before mid to
late afternoon. The very dry air above 8k ft or so will keep rain
chances near zero today and tonight without even considering the
fact that CAPE will be south of 100 J/kg for much of the forecast
area.

Could be a little breezy in the afternoon with the combination of
the weakening, but still well defined, gradient associated with the
low and 15-20 kt winds at the top of the mixed layer. A bit of
mixing during peak heating could lead to a few gusts approaching 20
mph. Given the amount of cloud cover gusts are likely to be pretty
infrequent. Highs today will range from near climo along the coast
to below climo inland, where cloud cover will be more pronounced.
Lows will run a little above climo with winds in the boundary layer
keeping things well mixed.

&&

.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
Model guidance suggests that a compact cutoff mid-level low
over upstate SC will gradually drift eastward through Wednesday
while lobes of vorticity pinwheel about its center. With plenty
of low-level moisture in place and southerly winds prevailing,
expect weak to moderate instability to develop during the day
amidst daytime heating. PVA attendant to the cutoff low should
help to enhance coverage of daytime pop-up convection across the
Pee Dee and interior Cape Fear regions while coastal areas
should stay largely dry owing to some drier air and subsidence
visible in forecast soundings. However, should lift ahead of a
lobe of vorticity be favorably timed with peak heating, there
could be convection along the sea breeze at the coast. Highs are
expected to reach the middle 80s beneath mixed clouds and sun.

Overnight, the loss of daytime heating should result in the
dissipation of most of the convection, particularly amid weak
vertical wind shear, although some light showers cannot be ruled
out near the cutoff low itself. Lows are forecast to fall into
the mid-upper 60s.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
A very gradual eastward translation of the mid-level trough axis
is expected through the weekend as prominent ridging tries to
build in behind it. On Thursday, the weak cutoff low is expected
to open up and become one with the general troughing in place.
However, the overhead passage of the lowest heights/coolest air
should result in a rather active day with at least scattered
showers and storms developing during the afternoon. Highs should
be able to reach the low-mid 80s before cloud cover and showers
limit further heating. On Friday, the trough axis should be east
of the area, resulting in more dry air and subsidence acting to
keep pop-up convection isolated at best.

Confidence decreases over the weekend as shortwaves diving
southward out of southeastern Canada should deepen the trough,
although this should occur far enough east to preclude any
precip from reaching the coast. Nevertheless, a backdoor front
should accompany this deepening of the trough late in the
weekend, bringing slightly cooler conditions with it. Given the
region`s position on the backside of a trough, subsidence and
dry air should continue to limit convective activity to isolated
coverage.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
Mostly MVFR this morning with VFR at ILM (never mind the
occasional swamp fog that is not representative of actual
conditions). Ceilings will gradually increase during the
morning with development of VFR expected late morning to early
afternoon. An occasional wind gust around 15 kt is possible
this afternoon, but due to very infrequent nature have not opted
to include any gusts in the TAFs. VFR through the evening but
may see some MVFR/IFR visibility come in after midnight given
moist boundary layer and decreasing winds overnight.

Extended Outlook...MVFR/IFR possible each morning through
Friday.

&&

.MARINE...
Through Tonight...
Seas continue dropping this morning with South Carolina
nearshore waters now below 6 ft, thus have cancelled the SCA for
AMZs 254/256. The SCA headline will continue for North Carolina
zones, but conditions should fall below SCA thresholds in the
next 8-10 hours.

Southwest winds across the waters today with speeds around 10 kt.
Few gusts approaching 20 kt are expected, but will not be
widespread. Seas continue dropping, with 3-4 ft this afternoon and 2-
3 ft overnight. An easterly swell will be dominant with a weak
southerly wind wave developing later in the day.

Tuesday Night through Saturday...
A weakly-defined pressure pattern will make for variable wind
directions through most of the week with speeds at or below 10
kts. Another high pressure wedge should yield a tighter gradient
and steady northeasterly winds on Friday and Saturday. Waves
hold in the 2-3 ft range, mainly driven by an easterly 10 sec
swell.

&&

.TIDES/COASTAL FLOODING...
High astronomical tides, excessive rainfall and lingering swell from
the prolonged onshore winds will lead to coastal flooding with the
morning high tides along the southeastern NC coast and the lower
Cape Fear River around and south of Wilmington. Water levels should
remain in the minor category and another round of advisories is
likely for this evening`s high tides, with the coast of northeast
SC likely being impacted this evening.

Other - Rip Currents:
Lingering easterly swell will remain conducive to cause a high
risk of rip currents for all beaches through today. Diminishing
winds will become south to southwest today, helping to subside
the strong longshore currents of the past few days. Decreasing
swells will lead to an overall decrease in rip current risk
through midweek.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
NC...Coastal Flood Advisory until 9 AM EDT this morning for NCZ106-
     108-110.
     High Risk for Rip Currents through this evening for NCZ106-108.
     Coastal Flood Advisory until noon EDT today for NCZ107.
SC...High Risk for Rip Currents through this evening for SCZ054-056.
MARINE...Small Craft Advisory until noon EDT today for AMZ250-252.

&&

$$

SYNOPSIS...ILM
NEAR TERM...III
SHORT TERM...ABW
LONG TERM...ABW
AVIATION...III
MARINE...III/ABW
TIDES/COASTAL FLOODING...ILM