Area Forecast Discussion
Issued by NWS Wilmington, NC

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FXUS62 KILM 261612
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
1112 AM EST Sun Nov 26 2023

.SYNOPSIS...
High pressure will give way to an upper level disturbance
accompanied with a modest chance of rain that will pass across
the area late today thru early Mon. A strong cold frontal
passage will occur later Monday and Monday night followed by
cold Canadian high pressure through mid week. Low temperatures
by Wed morning will run in the 20s to around 32 at the coast.
This should put an end to whats left of the growing season. The
high will push off the Carolina coasts and offshore late in the
week with a return to milder temperatures and increased chances
for rain as another upper disturbance impacts the area.

&&

.UPDATE...
No big changes with the latest update, although did adjust highs
down a tad, especially given the peskier than expected cloud
cover. Highs should generally be in the mid 50s with increasing
chances for light rain pushing in from the south this afternoon.

&&

.NEAR TERM /THROUGH TONIGHT/...
Warm advection will begin today atop a cool and shallow boundary
layer.  The day will begin with sun filtered through cirrus
followed by isentropic upglide-induced mid and then low
cloudiness; the end result is insolation hampered enough to
yield high temperatures that are once again on par with mid
winter. Light rain will spread into SC through the afternoon and
NC as we head into evening. Vertical motion is far from
impressive and as such QPF amounts will be light, generally a
tenth of an inch or so. Upglide shuts down in the 03-06Z time
frame and rain should advect offshore. Skies may not clear until
almost daybreak Monday keeping lows elevated about a category
above climatology.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
Southern stream upper s/w trof will be exiting off the Carolina
Coasts at the start of this period, taking any residual clouds
with it by midday. CFP slated during Mon with NW winds and CAA
combining as cold Canadian high pressure begins to ridge in from
the west. Highs Mon will see low to mid 60s, with the hier maxes
slated at the coast rather than inland. CAA continues Mon night
and winds should remain active enough to keep temps from
bottoming out, however guidance still painting low 30s inland
to mid-upper 30s at the coast. 540 thickness and 850mb 0 degree
Celsius does reach the FA by Tue morning. Another surge of cold
air and even drier air, especially lower levels, affects the FA
during Tue. Some progs indicate 850 mb temps to drop to 0 to
-2 C across the FA Tue night.

As a result, maxes Tue will be chilly with trouble breaking
into the 50s for highs. Tue night will see widespread 20s for
lows, with even the immediate coast see 32 or less readings.
This should put a final end to the growing seas for New Hanover
County and the sliver of coastline from Surf City to South
Santee River.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
Wednesday thru Thursday night will continue dry with below
normal temps as high pressure prevails. The airmass will slowly
modify thru the mentioned period, only reaching near or just
below normal for Thu nights lows. The modifying will be more
noteworthy at 850mb thru Thu night with WAA occurring aloft and
8H temps climbing to 6 to 10 degrees C by late Thu night.
Radiational cooling and sfc based inversion will keep the cold
air at the sfc Thu night. For Fri into Sat, this WAA reaches the
sfc and becomes more pronounced as the center of sfc high
pressure moves off the Carolina coasts Fri, with return
southerly flow, and a much more robust warming trend to ensue at
the sfc. During Sat, 8H temps reach 10-15 degrees C and models
indicate widespread 60s for highs Fri and possibly widespread
low 70s for Sat. There is an upper disturbance that pushes
across Sat that could result in scattered showers, however kept
chances on the low chance side given 6 to 7 days out in time.

&&

.AVIATION /16Z SUNDAY THROUGH THURSDAY/...
Confidence has decreased in the very near term as this 1000ft
stratocu is not being handled well by most guidance. The lowered
confidence is related to the fact that what little guidance
even has this moist layer keeps trying to erode it in a manner
that seems climatologically unlikely but in areas where these
clouds aren`t present it will be quite sunny. Moved the forecast
in a pessimistic direction for the next few hours in the hopes
that even the weak late November sun will start to erode the
boundary since mixing is forecast to be deeper than this layer
even if only marginally. IFR or LIFR ceilings move in (or remain
in areas that never manage to mix out) by evening whereas
visibility restrictions appear to be MVFR at worst.

Extended Outlook...VFR to return on Monday. Scattered showers Friday
and/or Saturday should not lead to significant or long lived
deviations from this flight category.

&&

.MARINE...
Through tonight...Lowered SCA as even 41013 now down to 5 ft.
Early on northerly winds in the 10-15kt realm but as the over
land wedge weakens speeds will taper off. Seas will abate but
a bit slowly as there is still an easterly swell component
with almost equal power as the wind wave according to spectral
density plots.

Monday through Thursday...
Tightened sfc pg Mon and CAA will combine Mon for gusty NW winds
that should remain below SCA thresholds. The sfc pg will
temporarily relax Mon night but then tighten Tue as another CAA
surge occurs but again remaining below SCA. Center of sfc high
over the inland Carolinas Wed, to slide off the Coasts later
Thu. GFS seems a bit overdone with an inverted sfc trof just
offshore Thu and thus have negated its affects across the local
waters. As a result, winds to diminish to 10 kt or less Wed into
Thu. Seas generally will peak Mon thru Tue, with a range of
short period seas top dominate, ie. lower near shore, due to
the offshore trajectory with the wind field. There-after seas
generally will be dominated by a small and fresh 7+ second
period ENE-E swell.

&&

.TIDES/COASTAL FLOODING...
Minor coastal flooding possible along the lower Cape Fear River
during the Monday morning high tide.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...None.

&&

$$
SYNOPSIS...ILM
UPDATE...RJB
NEAR TERM...MBB
SHORT TERM...DCH
LONG TERM...DCH
AVIATION...MBB
MARINE...DCH/MBB
TIDES/COASTAL FLOODING...


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