985
FXUS62 KMHX 222018
AFDMHX

Area Forecast Discussion
National Weather Service Newport/Morehead City NC
418 PM EDT Sun Sep 22 2024

.SYNOPSIS...
A weak backdoor cold front will gradually erode tonight, giving
way to a weak wedge of high pressure to the north. Next potential
frontal system doesn`t near ENC until at least the middle of the
upcoming week.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
As of 415 PM Sun...Backdoor cold front is pushing across eastern
NC this afternoon as upper ridge gradually builds overhead in
the wake of a passing shortwave trough offshore. Plenty of low
level moisture remains in place and abundant cloud cover to show
for it, but apart from some very spotty shower activity along
and south of the Neuse it remains dry. Little change in this
trend is expected in the near term, but overnight dry low-level
air is expected to advect in from the northeast, scouring out
any showers/clouds and ushering in clearing skies. There remains
some disagreement among hi-res guidance on the level of drying,
but the least aggressive models also show a slower frontal
passage than currently observed which would keep deeper moisture
in the area. Based on trends, continued to lean the forecast
towards a more clear skies forecast. Consequently, this also
raises the prospect of fog overnight especially for the coastal
plain as winds remain generally light.

Kept overnight lows on the cooler side, in the low to mid 60s.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
As of 415 PM Sun...Upper ridge will shift overhead as high
pressure weakly builds in from the north. This sets the stage
for a seasonable early autumn day across eastern NC with Tds in
the 60s and highs in the low 80s. Across NOBX and adjacent
areas, cool onshore NE flow will keep temperatures more tempered
in the mid to upper 70s.

&&

.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
As of 400 AM Sunday... Sfc ridging starts building in from the
north as a low lingers offshore to our northeast to start the
long term, gradually shifting further offshore to our east.
Seasonable temps through the period and dry Monday-Tuesday
evening. Rain chances increase mid to late week as ridging
weakens and a low treks across the Ohio Valley and Great Lakes
region. NHC has highlighted an area in the Gulf of Mexico with
70% chance of tropical development through 7 days, and it is too
soon to say what impacts, if any, ENC will have at this point
in time.

Monday-Tuesday:
High astronomical tides will be impacting OBX beaches Monday-
Tuesday. See TIDES/COASTAL FLOODING section for more
information.

High pressure centered over Maine and the Canadian Maritimes
has a ridge extending south over much of the east coast at the
surface, keeping us dry Monday and Tuesday. Further aloft a high
is centered to our south paired with lows to our west and east
put us in a weak omega block setup allowing the high to linger.
Seasonable temps with highs in the low 80s inland, upper 70s to
near 80 for beaches.

Wednesday-Saturday:
Uncertainty increases a lot towards the middle and end of next
week, as multiple synoptic features will be at play and slight
deviations result in large changes with the forecast. While
ridging continues to spread over ENC from the north Wednesday, a
low pressure system forecasted to be over the Great Lakes will
have a cold front trailing from it extending down to the Gulf
coast. This cold front could stall to our west due to the
ridging over us, or the ridge weakens and gives way to the low,
or the front sweeps north of us around the high. In addition to
the parent low over the Great Lakes and ridge overhead, we will
be keeping an eye on a tropical system that could initiate in
the Gulf Coast within 7 days. It is too soon to determine what
impacts, if any, we receive in ENC should this cyclone form. Due
to all this uncertainty, I opted to keep PoPs at Chc/Schc for
now through the remainder of the long term as a higher moisture
advection regime is more supportive of rain at the end of the
period.

&&

.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
SHORT TERM /through 18z Monday/...
As of 155 PM Sunday...Weak backdoor cold front, currently
draped just east of Highway 17, will continue to slowly push
westward towards area terminals over the next few hours. Mix of
VFR and MVFR currently in place will change little through the
rest of the day, although behind the front more prevailing MVFR
is likely. Isolated shower threat will linger along the front
into the afternoon before giving way to dry conditions by
nightfall.

Guidance has trended more aggressive on fog threat inland
tonight as low-level clouds gradually erode. Now carry an
explicit IFR mention for the coastal plain terminals with
visibility, while EWN is lower confidence and maintained an MVFR
forecast here. All sites return to VFR by Mon.

LONG TERM /Monday through Thursday/...
As of 430 AM Sunday...With high pressure overhead, there are
fog chances Monday and Tuesday morning. Wednesday onwards
moisture advection regime will support lower ceilings and/or
reduced visibilities, although it is too soon to determine
specifics.

&&

.MARINE...
SHORT TERM /Through tonight/...
As of 415 PM Sunday...Backdoor front is pushing across the
waters this afternoon, bringing northeast to easterly winds to
all waters except Onslow Bay where pre-frontal southwesterly
winds prevail. The surge as been a bit weaker than expected,
only reaching up to 10-15 kt, and as such seas have dropped
slightly sitting at around 4-5 feet.

Front will clear the waters later tonight, ushering in
northeasterly winds area wide but still at around 10-15 kt. The
bigger concern remains growing swell from a distant cyclone well
offshore, which will result in gradually building seas from the
northeast into tomorrow. Seas will be highest north of Cape
Hatteras, peaking at 6-8 feet late tomorrow afternoon. SCA
headlines remain in good shape, leaning heavily on an NBM
forecast given the in-house NWPS model tends to underdo wave
heights in northeast flow regimes.

LONG TERM /Monday through Thursday/...
As of 445 AM Sunday...SCA In Effect until 12Z Wednesday for
coastal waters north of Ocracoke Inlet.

Sustained variable winds 10-15 kt Monday before dropping back
down to 5-10 kt and veering to become more easterly Tuesday
night into Wednesday. SCA in effect for waters north of
Ocracoke Inlet as 6+ feet waves are expected from the low
offshore through early next week. Seas will be 2-7 ft
Monday/Tuesday before dropping down to 2-5 ft Wednesday/Thursday
as the low offshore results in higher swell. Waters off Crystal
Coast and coastal Onslow will be a bit protected from the more
easterly swell courtesy of Cape Lookout, and will be on the
lower end of these wave height ranges. OBX (particularly north
of Hatteras) and the Gulf Stream will not be protected and will
see the higher values in the ranges above.

&&

.TIDES/COASTAL FLOODING...
As of 500 AM Sat... Extended the Coastal Flood Advisory to cover
Tuesday afternoon`s high tide with this update.

Otherwise, no real changes to the forecast thinking as coastal
flooding will continue to be a threat given the higher than
normal astronomical tide cycle today and through Tuesday
afternoon during high tide each day. Coastal Flood Advisories
remain in effect for all oceanside coastal areas into Tuesday
afternoon`s high tide. Increased swell from a low offshore may
bring minor overwash concerns Tuesday and into midweek for the
OBX north of Cape Hatteras, although recent guidance has backed
off some on the strength of this offshore low, which may lessen
the risk of coastal impacts.

&&

.MHX WATCHES/WARNINGS/ADVISORIES...
NC...Coastal Flood Advisory until 5 PM EDT Tuesday for NCZ195-196-
     199-203>205.
     Beach Hazards Statement until 8 PM EDT this evening for NCZ203-
     205.
MARINE...Small Craft Advisory until 8 AM EDT Wednesday for AMZ150-152-
     154.

&&

$$
SYNOPSIS...MHX
NEAR TERM...MS
SHORT TERM...MS
LONG TERM...RCF/RJ
AVIATION...MS/RCF/RJ
MARINE...MS/RCF/RJ
TIDES/COASTAL FLOODING...MHX