471
FXUS62 KMHX 150840
AFDMHX

Area Forecast Discussion
National Weather Service Newport/Morehead City NC
440 AM EDT Sun Sep 15 2024

.SYNOPSIS...
High pressure remains wedged across the mid-Atlantic while low
pressure developing off the southeastern coastline drifts
northward today and Monday. 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 400 AM Sun...Weather pattern remains largely stagnant
this morning as strong mid-level ridge continues to wobble over
the northeastern CONUS while weak low pressure continues to
slowly organize along a stalled frontal boundary off the coast
of South Carolina. At the surface, high pressure wedge continues
to hold strong over the mid-Atlantic and central Carolinas
while the Gulf Stream low remains stationary. There is a very
weak offshore trough north of Cape Hatteras that is acting to
support some very light shower activity across the north, but
this is expected to dissipate later today.

This pattern will not change much in the near term. The upper
ridge is keeping deeper moisture and stronger lift shunted just
south of our area (seen on radar as heavier rainfall is focused
along and south of Cape Fear), and apart from a few stray
showers along the southern coast (and, at least for the morning,
the northern tier) dry conditions prevail. Widespread cloudiness
continues thanks to moist easterly onshore flow, and expect this
to hold through the day. Like yesterday, expect precipitation
coverage to expand modestly in the afternoon with a stray
thunderstorm possible as CAPEs hover between 500-1000 J/kg. Most
likely areas to see rain remain along area beaches.

NE to E winds continue to steadily increase through the day as
the Gulf low slowly strengthens. At their peak, winds this
afternoon will reach 15-20 mph with frequent gusts up to 30 mph
(up to 35 mph OBX). Highs remain modestly below average as low
dense overcast inhibits insolation, in the low 80s.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/...
As of 400 AM Sun...Gulf low will begin to gradually lift
northward overnight as upper ridge weakens. Isolated to widely
scattered shower activity will persist along the coast through
much of the overnight hours, especially along the Crystal Coast,
but heavier rainfall is expected to encroach from the south as
early as Monday morning as deeper plume of 2"+ PWATs drifts back
northward. Rainfall totals overnight will remain relatively
light (a half inch or less), with more robust precipitation
expected during the day Monday.

Prior to the onset of rain, cloudy and breezy conditions persist
overnight as lows once again hover in the upper 60s to low 70s.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
As of 4 AM Sun... Eastern North Carolina will remain unsettled
through the entire period as an impactful low looks to bring
several hazards to the area Mon into Tue. Beyond that, troughing
over the Eastern Seaboard will continue to bring daily chances
for showers and thunderstorms across the region into next
weekend.

Monday and Tuesday...We start the long term period out with
unsettled weather. The upper levels will be denoted by deepening
troughing across the Southeast. As this trough deepens, an
incoming shortwave from the west will round this troughs base.
At the same time, a mid level low off the Southeast Coast tracks
north to northwest towards the Carolinas and becomes absorbed
within this deepening trough on Tue. At the surface, our main
weather maker for Mon and Tue will be impacting the area. Low
pressure system is currently in the process of developing and is
attached to a frontal boundary off the Southeast Coast. Latest
guidance still continues to deepen the low on Sun detaching it
from the aforementioned frontal boundary with this surface low
then tracking north to northwest and potentially gaining sub-
tropical or tropical characteristics as it nears the coast on
Mon. The low then continues inland on Tue eventually lifting
north of the region by Tue afternoon allowing for much more
benign weather to finally begin to overspread ENC for at least a
brief time period Tue afternoon and evening. If this forecast
were to hold, this would bring heavy rain (with HREF
neighborhood probs of >5" of rain over 24 hours close to 40-60%
along the Crystal Coast and closer to 10-30% further north), a
low end severe threat, gusty winds with the potential for
widespread 25- 35+ mph E`rly wind gusts, dangerous marine
conditions, minor coastal flooding, beach erosion, and ocean
overwash to ENC. (SEE COASTAL FLOODING AND HYDRO SECTION FOR
MORE INFORMATION)

Have two important caveats to the above however. The first is,
regardless if this system remains non-tropical or gains sub-
tropical or tropical characteristics, impacts will be similar so
don`t latch on to whether it become tropical or not. The second
is, even with us getting close to the time this low will begin
to impact the area, there still remains lower than average
confidence with the lows eventually track and strength which
will have significant impacts to the conditions we see from this
low. Latest 00Z guidance has shifted south with GFS ensembles
latching on to more of a southern NC or even SC landfall as
early as tonight while EURO ensembles still promote a threat
from SC to the Crystal Coast while also being weaker and
slightly slower to reach the coast than the 12Z ensemble
guidance. With this in mind continue to keep a close watch on
the latest forecast as any shifts in this lows eventual track
and timing will have significant impacts on the forecast going
forward.

Otherwise expecting below avg temps across ENC Mon and Tue with
highs only getting into the 70s to low 80s each day while lows
get down into the 60s to low 70s.

Wednesday into the weekend... Previously mentioned upper trough
will remain over the Eastern Seaboard through the end of the
week while at the surface previously mentioned low is forecast
to be to the north and likely dissipated. As we get into the
weekend there is increasing uncertainty with the forecast as the
upper trough over the Eastern Seaboard looks to cutoff into an
upper low in the Southeast as upper ridging builds across the
Northeast but there is a rather large spread in timing and depth
of the cutoff low this weekend across all available guidance so
the forecast beyond Friday is low confidence.

Either way, daily chances for showers and thunderstorms will
remain possible across ENC into the weekend 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 /07Z SUNDAY THROUGH THURSDAY/...
SHORT TERM /through 06Z Mon/...
As of 145 AM Sun...Primarily MVFR conditions in place early this
morning in steady northeasterly flow between the inland wedge of
high pressure and a developing low a couple hundred miles
offshore to our south. Cig heights have been drifting lower
this morning and would not be surprised to see some brief drops
to IFR in the pre-dawn hours. Expanded TEMPO IFR forecast to
both PGV and ISO. Along the coast, weak band of broken showers
will continue through much of the period, posing a risk mainly
for EWN/OAJ.

Conditions are forecast to improve to VFR during the day as
winds increase markedly, gusting up to 20-25 kt in the afternoon
hours inland (and up to 30 kt for OBX terminals) with shower and
iso thunder risk persisting, still focused along the southern
coast. Lower cigs return from south to north tonight into Mon
morning as low lifts towards the Carolina coast, although
confidence in their onset timing is lower than average.


LONG TERM /Sunday Night through Wednesday/...
As of 4 AM Sun... Continued unsettled weather will bring daily
chances for sub-VFR conditions across ENC especially Mon and
into Tue as a low pressure system is forecast to impact the area
bringing a threat for widespread shower and thunderstorm
activity as well as low clouds and reduced visibility. Winds
will generally remain NE-E at 10-20 kts with gusts up near 20-30
kts through Monday before winds shift to a more SE`rly
direction and become much lighter closer to 5-10 kts Tue into
Wed as the aforementioned low moves to the north. After the low
moves to the north we will still see at least a low end threat
on Wed and Thurs for sub-VFR conditions as daily chances for
afternoon and evening showers and thunderstorms will remain.

&&

.MARINE...
SHORT TERM /through Sunday/...
As of 420 AM Sun...Roughly marine conditions already in place
this morning as a Gulf Stream low meanders south of a persistent
high pressure ridge over the central Carolinas, resulting in
breezy northeasterly winds across the waters. Latest
observations show speaks of 15-25 kt with frequent gusts up to
30 kt. Seas are now averaging 7-10 feet across all zones.

Winds will continue to slowly increase through the day as the
aforementioned low begins to lift north. Guidance shows high
probabilities (>80%) of Gale force gusts starting across the
outer portions of Raleigh and Onslow Bays by sunrise this
morning, persisting for the next 24 hours. Because of this,
upgraded the Gale Watch to a Warning for the waters south of
Cape Hatteras. Strong SCA conditions are still expected across
all remaining waters, and no other changes to headlines were
made. Seas continue to build, reaching a peak of 10-15 feet just
before dawn on Monday south of Hatteras.

LONG TERM /Sunday Night through Wednesday/...
As of 4 AM Sun... Dangerous marine conditions are still
forecast across our waters on Mon and Tue as a low pressure
system impacts the Carolinas during this timeframe. Latest
guidance suggests we start the period out with widespread 20-30
kt NE-E winds with gusts up around 30-35 kts as well as
widespread 8-12 ft seas across our coastal waters. This will
keep any ongoing SCA`s in place on Mon and while recently
hoisted gale warnings should end by 12Z Mon there is a low end
threat if aforementioned low is slightly stronger than currently
forecast low end gale conditions could persist into Monday
morning across our southern waters before easing. As low moves
inland Mon night into Tue expect marine conditions to gradually
improve from south to north with winds easing down to 15-20 kts
with gusts up around 20-25 kts by Tue morning and veering to a
SE and eventually SW direction while seas fall down to 5-8 ft
along our coastal waters. This should allow our inland rivers
and sounds to fall below SCA criteria by Tue morning. Winds and
seas fall even further Tue and Wed with winds remaining S`rly at
10-15 kts while seas along our coastal waters finally lower
down to 3-5 ft by Wed morning. This should then end SCA criteria
across all waters with more benign boating conditions forecast
for Thurs. Daily chances for showers and thunderstorms will
remain possible through the period with locally enhanced winds
and seas possible within the strongest storms that may develop.

&&

.HYDROLOGY...
As of 425 AM Sun...Widespread heavy rain is expected late
tomorrow through Tuesday as low pressure develops to our south
and pushes northward. Abundant tropical moisture with this
system will lead to extremely heavy rainfall rates over areas
that have become saturated over the last week. Where the
heaviest rainfall sets up remains uncertain due to larger than
average spread in model guidance, but confidence in heaviest
rainfall remains highest along the Crystal Coast where storm
total 4-6 inches of rain is possible. A more widespread 2-4
inches is forecast for the rest of ENC. Because of the
aforementioned model spread, opted to delay any flood headlines
until later today.

&&

.TIDES/COASTAL FLOODING...
As of 435 AM Sun...There will be potential for minor to
moderate coastal flooding early this week as winds strengthen in
association with a developing low pressure system to our south
over the Gulf Stream. Additionally, coastal flooding may be
worsened due to the astronomically high tide cycle we are
entering. Ahead of this system, strong NE/ENE winds will buildup
water along the SE portion of the Pamlico Sound as well as the
Neuse, Bay, and Pamlico Rivers. Oceanside, high water levels in
addition to strong wave run up will likely produce ocean
overwash along NC 12 on the Outer Banks at times of high tide.
The severity of these potential impacts is not yet fully known
due to the difference in track and intensity solutions for this
low pressure system. Additionally with this system we can
expect a high threat of rip currents, rough and dangerous
surf/shore break, and beach erosion.

Forecast impacts changed little this morning. Coastal Flood
Advisories for 1-2 feet of inundation above ground level remain
for the Outer Banks as well as areas along the aforementioned
inland rivers, running from this afternoon to late Monday. A
High Surf Advisory remains for all area beaches running until
Tues AM.

&&

.MHX WATCHES/WARNINGS/ADVISORIES...
NC...Coastal Flood Advisory from 2 PM this afternoon to 9 PM EDT
     Monday for NCZ080-094-194>196-199-203>205.
     Beach Hazards Statement from 8 AM EDT this morning through
     this evening for NCZ195-196-199-203>205.
     High Surf Advisory from 2 PM this afternoon to 8 AM EDT
     Tuesday for NCZ195-199-203.
     High Surf Advisory until 8 AM EDT Tuesday for NCZ196-204-205.
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.
     Gale Warning until 8 AM EDT Monday for AMZ154-156-158.

&&

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