525
FXUS62 KMHX 221413
AFDMHX

Area Forecast Discussion
National Weather Service Newport/Morehead City NC
1013 AM EDT Sun Sep 22 2024

.SYNOPSIS...
A cold front will move south through eastern North Carolina over
the next 24 hours, with high pressure moving in behind it by
Monday. Next potential frontal system doesn`t near ENC until at
least the middle of the upcoming week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
As of 1015 AM Sun...Aforementioned shower activity has come to a
close this morning and expect dry conditions until this
afternoon ahead of an approaching weak cold front. Otherwise,
prior forecast is on track.

To the north of ENC, another surface low and frontal boundary
has taken shape over central VA. This low, and an associated
cold front, is forecast to shift south into NC as a shortwave
moves through the Mid-Atlantic States. The front is forecast to
reach the NRN OBX by late-afternoon, with increasing low clouds
and cooling temps. Sometimes this type of setup can support a
faster frontal passage, and we`ll be watching trends through the
day. Along and ahead of that front, daytime heating of a
modestly moist boundary layer should support MLCAPE up to around
1000j/kg by this afternoon, especially across southwestern
sections of ENC. This will be occurring as large-scale
subsidence develops on the backside of the departing Mid-
Atlantic shortwave. An area of mid-level drying is forecast
during this time as well. Despite the favorable timing of the
front with peak heating, I expect the subsidence and drier air
to limit the coverage of convection this afternoon. It may even
be a scenario where we see isolated showers, and not much of a
thunderstorm threat. It should be noted that deep layer shear
around 30kt could support a stronger thunderstorm, but because
of the limitations to deeper convection, I am not expecting a
severe weather risk today.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/...
As of 300 AM Sunday...

 - Turning a bit cooler tonight

A cold front is forecast to slide south through ENC this
evening and tonight, bringing lower dewpoints and cooler
temperatures. Guidance differs on how much cloudcover will
accompany the front, which leads to differences in how cool it
will get tonight. For now, I kept lows in the low to mid 60s,
with the expectation that skies will be partly to mostly cloudy.
Should clouds be less prevalent than forecast, some inland
areas could see lows in the upper 50s. I expect there will be
enough mixing with the front tonight to limit the fog potential.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
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 /14Z SUNDAY THROUGH THURSDAY/...
SHORT TERM /through 12z Monday/...
As of 700 AM Sunday...

 - SHRA/low-end TSRA risk this AM and again this afternoon

 - Sub VFR CIGs possible at times over the next 24 hrs (40-60%
   chance)

Increasing low-level moisture has aided in the development of
SCT/BKN low CIGs and isolated SHRA across parts of eastern NC
recently. The SHRA activity should continue through about 15z,
then decrease as the better lift shifts SE and offshore. There
hasn`t been any lightning noted with this activity recently, but
with weak instability in place, the risk isn`t zero this
morning. Later today and into tonight, a cold front will slide
south across the area, leading to a northeasterly wind shift.
Additionally, guidance is showing an increased risk of low
stratus (MVFR, or lower, CIGs) with this front thanks to a
cooling and moistening post-frontal airmass moving in. Ahead of
this front, isolated afternoon and early evening SHRA and TSRA
will again be possible (10-30% chance), especially across
southwestern sections of ENC.

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 300 AM Sunday...

 - Elevated seas continue across the central and northern
   coastal waters

 - Cold front to bring a northeasterly wind shift late today
   into tonight

Light southerly winds of 5-10kt are expected for much of the
day across most waters today. By late this afternoon, and
especially this evening, a cold front will push south through
area waters, and will be accompanied by northeasterly winds
building to 10-20kt. For now, winds are expected to remain below
25kt with this northeasterly wind surge, but we`ll monitor
trends in obs upstream, and in model guidance, in case this risk
were to increase. For the central and northern coastal waters,
seas remain elevated in the 4-6 ft range. A longer period swell
of 5-7ft at 11 seconds is forecast to arrive this evening and
tonight thanks to low pressure off the New England Coast. In
light of this, we`ll continua the SCAs for coastal waters north
of Ocracoke Inlet. A few showers and thunderstorms may
accompany the front later today and tonight, but widespread
thunderstorm activity is not expected.

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...RM/MS
SHORT TERM...RM
LONG TERM...RJ
AVIATION...RM/RJ
MARINE...RM/RJ
TIDES/COASTAL FLOODING...MHX