831
FXUS62 KMHX 141101
AFDMHX

Area Forecast Discussion
National Weather Service Newport/Morehead City NC
701 AM EDT Sat Sep 14 2024

.SYNOPSIS...
A surface trough off the coast of the Carolinas will weaken
today as high pressure remains wedged across the mid-Atlantic
and central Carolinas. Low pressure developing off the Southeast
U.S. coastline impacts the area over the weekend and into early
next week, before moving inland mid-week. Troughing will remain
over the Eastern Seaboard through next week as well keeping
unsettled conditions across ENC.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
As of 700 AM Sat...No changes to the previous forecast. Mid-
level Rex block remains in place over the eastern CONUS this
morning as the remnants of Francine continue to swirl over the
lower MS River Valley, while upper ridge continues to linger
over the Great Lakes and southeastern Canada. Mid-level
convergence axis draped over the Carolinas will eventually be
shunted southward this evening by a shortwave trough currently
diving out of the Gulf of Maine, and the upper ridge is forecast
to expand southward ushering in subsidence and drier air.

At the surface, weak coastal trough continues to linger and
provide enough lift for sporadic shower activity along the
coast while wedge of high pressure remains locked in place for
yet another day. Although the trough will be weakening through
the day, it will continue to be a focal point for shower and
isolated thunderstorm activity especially for coastal locations
south of Oregon Inlet. Coverage will be at its most abundant
during the diurnal maximum. PWATs will not be as high as
yesterday, and with weaker upper level support do not expect to
replicate the same impressive rainfall totals. In general,
totals should remain below an inch but a few isolated higher
totals of an inch or two are possible along the immediate coast.
Since this is where the heaviest rain fell yesterday, this may
be enough to reintroduce some minor flooding issues in
vulnerable locations.

Cloud cover and brisk northeasterly flow (gusting to 25-30 mph
at times) will keep temperatures once again slightly below
average for mid-September, in the upper 70s to around 80.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
As of 340 AM Saturday...The mid-level ridge will continue to
slowly expand southward, pushing convergence axis and deeper
moisture further south as PWATs fall to 1-1.5" area-wide.
Easterly onshore flow means a spotty shower threat is still not
out of the question along the coast into Sunday morning, but
coverage will be increasingly isolated. Surface wedge still
doesn`t budge, keeping low-levels saturated and yet another
night of low clouds, especially west of Highway 17. Temperatures
linger on the warmer side once again, with lows in the upper
60s to low 70s.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
As of 520 AM Sat...An unsettled weather pattern is forecast for
the entire period as a rex block will remain over the Eastern
Seaboard through Sunday and into early next week keeping a
blocking ridge centered to the north and a stalled frontal
boundary and associated developing low pressure system off the
Southeast coast. On Monday and into Tuesday, low pressure will
slowly track northwards potentially impacting ENC during this
timeframe. Afterwards troughing will remain over the Eastern
Seaboard into Friday keeping things unsettled across the area
with daily chances for showers and thunderstorms. With steady
onshore flow over the next several days temps will remain at or
below avg through the period as well.

Sunday into Tuesday... There has been some clarity in the forecast
since the previous update though the trend has certainly not been
our friend this go around as there is an increasing likelihood
of low pressure impacting ENC Mon into Tue bringing a threat for
several hazards to the area. Rex block remains in place into
Tue as a ridge of high pressure remains centered to the north
while troughing remains over the Southeastern CONUS. In
addition to this, a mid level low is also forecast to get spun
up across the Sargasso Sea Sun into Mon, eventually becoming
absorbed into the troughing. This will combine with an incoming
shortwave from the west to deepen the aforementioned troughing
across the Southeast on Mon and Tue allowing the previously
mentioned ridge to weaken slightly on Tue night. At the surface,
high pressure ridging will continue to wedge down into the
Carolinas while a stalled front remains well off the coast on
Sun. The interaction between these two features will continue
to keep the pressure gradient tight allowing for blustery E`rly
winds Sun and into Mon.

Surface low pressure does begin to develop on Sun and it is now
looking increasingly likely that it will detach from the front
and track N to NW Mon into Tue potentially impacting ENC as a
sub-tropical or tropical low during this timeframe. EURO and
its ensembles have come on board with the GFS and its ensembles
bringing a low pressure system either into or near the
Carolinas Mon night into Tue morning before this low pushes
further north into the Mid-Atlantic and weakens. While there
has been increasing confidence in low development, there remains
low confidence in the exact track and strength of the low as it
approaches the region with both EURO and GFS ensembles having a
broad envelope of solutions for the overall outcome of the
system. This in turn results in lower confidence in what the
exact impacts are across ENC. As of this update the NHC has
recently increased 3/7 day development chances to 20%/50% and
any development that would occur looks to be fairly rapid so
lead time on this systems development will be unusually low
given the circumstances.

Regardless of if this system is tropical or not, there remains
the potential for heavy rain, coastal impacts, strong winds,
and dangerous marine conditions through Tue (SEE COASTAL FLOOD
AND HYDRO SECTIONS FOR MORE INFO) Temps will remain at or below
avg through Tue as well.

Wednesday through end of the week... Previously mentioned upper
trough will remain over the Eastern Seaboard through the end of the
week while at the surface whatever low develops early this week will
have moved to the north and likely dissipated by Wed. Either way,
daily chances for showers and thunderstorms will remain possible
across ENC into the end of the week as troughing continues to remain
a focus for shower and tstm activity. Will note however, winds will
finally ease by Wed as the pressure gradient relaxes as a weakness
in the ridge centered to our north briefly develops, though a second
ridge of high pressure does begin to extend south into the area by
Friday. Otherwise continued onshore flow will keep clouds around the
region while temps remain at or below avg.

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM /through 12 Sun/...
As of 700 AM Sat...Conditions have improved more quickly than
expected, now VFR apart from some spotty IFR inland. Expectation
is for brief MVFR to develop this morning while mixing layer
remains lower, but quickly lifting to VFR just before 18z as
coastal trough decays and drier air filters in from the north.
Some spotty shower activity remains possible through this
afternoon for EWN/OAJ. Gusty conditions prevail across all
terminals with gusts to 20-25 kt likely especially across the
inner coastal plain.

IFR conditions make a return tonight across the coastal plain as
wedge remains in place. Once again, highest confidence is for
PGV/ISO and to a lesser extent OAJ.

LONG TERM /Sunday through Wednesday/...
As of 330 AM Sat... No significant changes in the forecast
outside of an increasing likelihood of an impactful low pressure
system moving across the region on Mon and Tue. Daily chances
for showers and thunderstorms across ENC will once again bring
daily chances for sub-VFR conditions through the entire period
with the highest threat to see sub-VFR conditions on Mon and Tue
as the aforementioned low makes its way across the area. Winds
will generally remain NE-E at 5-15 kts with gusts up near 20-25
kts through Monday before winds shift to a more SE`rly direction
and become much lighter Tue into Wed as the aforementioned low
moves to the north.

&&

.MARINE...
SHORT TERM /through Saturday/..
As of 345 AM Sat...Poor boating conditions remain in place
through the short term as high pressure wedge and northeasterly
wind regime refuse to relent. Area observations show winds of
10-20 kt, with the strongest winds across Raleigh and Onslow
Bays which are gusting to 25-30 kt at times. Offshore, seas are
hovering at around 5-7 feet.

Weather pattern will change little through the day, and as such
winds will remain at currently observed levels through the short
term. The persistent fetch, however, will act to steadily build
seas and by sunrise on Sunday wave weights are likely to reach
between 7-10 feet, with the roughest waters focused from Cape
Lookout northward. Seas may be a few feet higher along the Gulf
Stream.

Forecast winds have increased from the previous update. This
necessitated adding all remaining inland waters to the suite of
Small Crafts, extending through the weekend. All other existing
headlines are in good shape and did not need any changes.


LONG TERM /Sunday through Wednesday/...
As of 345 AM Sat...No significant changes on this update as
dangerous marine conditions will continue across our waters
through at least Tue and possibly into Wed as a tight pressure
gradient and eventually a low pressure system impact our
waters. High pressure centered to our north will continue to
interact with a stalled front to our south keeping the pressure
gradient tight Sun into Mon. This will result in ongoing 15-25
kt E-NE`rly winds with 25-30 kt gusts to start the period with
these winds persisting into Mon. Low pressure system develops
Sun night and eventually tracks N to NW across our area Mon
night into Tue. This low may gain some sub-tropical or tropical
characteristics as this occurs, but regardless if this low
becomes tropical or not, marine impacts will be the same. Wind
gusts closer to 30-35 kts will be possible at times especially
as the aforementioned low moves through the area, though
confidence is too low to upgrade ongoing SCA`s just yet.
High pressure eventually weakens Tue into Wed allowing this
aforementioned low to push north away from our waters and allow
the pressure gradient to relax resulting in winds easing down to
10-15 kts with gusts up near 20 kts at times coming from a SE-
SW direction from Tue afternoon on into the end of the period.

Seas will remain rather elevated through just about the entire
period with areas north of Cape Lookout seeing 8-12 ft seas on Sun
increasing to 11-15 ft seas by Mon. Further south across the more
protected waters of Onslow Bay, 4-8 ft seas will build closer to 5-9
ft Sun night into Monday. These elevated seas will persist into Tue
morning before rapidly lowering Tue afternoon and evening as the
aforementioned low moves through the area and to the north
allowing the pressure gradient and therefore winds to finally
ease. Expecting seas to lower to 3-6 ft across Onslow Bay by Wed
morning while further to the north seas will lower from 11-15
ft Tue morning down to 5-6 ft by Wed morning. Daily chances for
showers and thunderstorms will remain possible through the
period as troughing remains entrenched over the Southeast.

&&

.HYDROLOGY...
As of 520 AM Sat...There continues to be a signal for multiple
rounds of heavy rainfall associated with the development of a low
pressure system off the Southeast U.S. coastline Mon into Tue.
We`ll continue to monitor trends in guidance, as a renewed
flooding risk may develop during this timeframe.

&&

.TIDES/COASTAL FLOODING...
As of 520 AM Fri...Persistent moderate to gusty ENE winds will
continue into Mon/Tue and could result in very minor (nuisance,
1 ft agl or less) water level rises for areas adjacent to the
western/southern Pamlico Sound, Neuse/Bay/Pamlico/Pungo Rvrs as
well as the oceanside.

Low pressure system is expected to develop off the SE coast this
weekend and early next week. NHC has increased the probability
of tropical development to 50%. Regardless of tropical
development, this system is expected to bring coastal impacts.
Though there is still some uncertainty with respect to timing
and magnitude of those impacts, they will likely include: an
elevated rip current risk for area beaches, minor coastal
flooding, rough surf, beach erosion and localized ocean
overwash. Coastal issues could also be exacerbated by the
upcoming King Tide.

&&

.MHX WATCHES/WARNINGS/ADVISORIES...
NC...Beach Hazards Statement through this evening for NCZ196-
     203>205.
MARINE...Small Craft Advisory until 8 AM EDT Tuesday for AMZ131-135>137-
     230-231.
     Small Craft Advisory until 8 AM EDT Wednesday for AMZ150-152-
     154.
     Small Craft Advisory until 6 AM EDT Wednesday for AMZ156-158.

&&

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