-- Discussion containing changed information from previous version are highlighted. --
292
FXUS62 KMHX 241757
AFDMHX

Area Forecast Discussion
National Weather Service Newport/Morehead City NC
157 PM EDT Tue Sep 24 2024

.SYNOPSIS...
High pressure will remain anchored to the north through midweek as a
warm front approaches eastern North Carolina from the west and
stalls. A potential tropical system will pass through the
Southeast US and bring a period of heavy rain and gusty winds to
the area.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
As of 1015 AM Tue...Isentropically driven precip is holding
together much better than expected, and near term guidance is
handling the current band of rain poorly. Near term PoPs were
largely hand drawn to capture radar trends. Rainfall is not
particularly intense as it moves into more stable air east of
the warm front, and the flash flooding threat is low.

Low levels continue to gradually moisten today as 850 mb flow
turns southwesterly and surface winds veer further to the east
and south as subtle warm front moves newrd. CAMs cont to
indicate the front being a focal point for isolated shower and
thunderstorm development as CAPEs climb to 500+ J/kg, especially
west of Highway 17. HREF probs highest across far wrn coastal
plain where pops remain in the chc range, with dry conditions
east of hwy 17 and thus cont to indicate a dry fcst here.
Persistent ridging aloft will keep coverage limited, but with
30-35 kt of 0-6km shear a stronger storm is not out of the
question.

Despite increasing low-level thicknesses, plenty of cloud cover
will keep temperatures tempered and no higher than the low 80s,
with 70s on the beaches with cont onshore flow.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
As of 330 AM Tue...A few renegade showers or storms for the
first part of the evening for far wrn zones, though most of the
area will be dry for the remainder of the night, with cont cloud
cover keeping temps on the mild side, with lows generally in
the upr 60s.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
As of 200 AM Tuesday...

 - Above normal temperatures mid-week

 - Watching the tropics late Thursday into Friday

Wednesday: A potent upper level shortwave is forecast to get cutoff
over the Mid-South on Wednesday, helping pull a potential tropical
system north into the eastern Gulf of Mexico. East of the cutoff
low, a warm front is forecast to lift north through North Carolina.
While a low-mid level dryslot is forecast to overspread ENC in the
wake of the warm front, there may be enough lift, moisture, and
instability to support morning showers and thunderstorms, especially
across northern sections of ENC. The forecast reflects this
expectation, followed by drying noted from south to north through
the day and into the night.

Thursday-Friday: The main item of interest during this time will be
the track of Potential Tropical Cyclone #9. 00z deterministic and
ensemble guidance continue to be fairly well clustered on an inland
track through the Southeast U.S. after making landfall along the
Gulf Coast of Florida. The most notable change is a slight eastward
shift noted in the ensemble mean track. Based on the latest
available guidance, it appears that we`re getting some clarity on
what the impact to ENC may be. If the current forecast track from
the NHC holds, ENC will remain well east of the center of
circulation. However, strong moisture advection east of the center
should allow a plume of tropical moisture to quickly overspread the
coastal Carolinas Thursday night into Friday. At the same time, a
broadly diffluent flow aloft plus increasing WAA should support a
period of strong forcing, leading to a quick period of moderate to
heavy rain and scattered thunderstorms. While quick-hitting,
guidance has been showing a consistent signal for heavy rain focused
on Thursday night and Friday for at least a portion of ENC.
Instability is forecast to be low, but strong shear/helicity to the
east of the tropical system will need to be watched for a
conditional tornado risk.

Additionally, a strengthening pressure gradient, modest mixing, and
a strong southerly LLJ should allow a period of gusty winds to
accompany the rain and thunderstorms on Friday. This will especially
be the case along the coast. With the subtle eastward shift in the
guidance, winds and precip have increased some compared to the
previous forecast. While this currently appears to be a quick-
hitting scenario for ENC, it has been very wet of late, so it may
not take as much rain to cause some hydro issues.

What`s outlined above appears to be the most likely scenario based
on the latest NHC track and model guidance. Stay tuned, though, as
any shift west, or east, would lower or increase the impacts,
respectively.

Saturday-Tuesday: In the wake of the tropical system, a backdoor
cold front is forecast to move through ENC on Saturday, and may be
accompanied by a few showers. Temperatures will take a step down as
well. By early next week, a surface low may develop off the coast of
ENC as the Mid-South cutoff low finally opens up and moves east
towards the Southeast U.S. coast. This is several days out, but is
worth noting as it could bring another round of gusty winds and
heavy rainfall.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
-- Changed Discussion --
SHORT TERM /through 18z Wed/...
As of 155 PM Tue...Primarily VFR conditions in place across area
terminals as a warm front lifts northeastward across the region.
Associated bank of showers and storms has fallen apart as it
hits drier air, but showers and a few storms remain possible
this afternoon across the coastal plain as a more moist and
unstable airmass fills in behind the front. This threat is
diurnal, and by nightfall the risk of showers will be low (10%
or less) although a couple offshore showers may threaten MRH and
vicinity. Low stratus is possible across the coastal plain early
AM. VFR will return by late Wed AM.


LONG TERM /Wed through Sat/...
As of 200 AM Tuesday...

 - Watching the tropics late Thursday-Friday

SCT SHRA and TSRA may be ongoing Wednesday morning, but a general
lull in TSRA activity is expected for most of Wednesday and
potentially even into Thursday. Thursday night into Friday, a
tropical system is forecast to pass well west of eastern NC, but
still be close enough to produce a period of gusty winds, RA, TSRA,
and sub-VFR conditions. Sub-VFR conditions and SHRA may linger into
Saturday.
-- End Changed Discussion --

&&

.MARINE...
SHORT TERM /Through Tonight/...
As of 330 AM Tue...Cont high seas above 6 ft north of Ocracoke
as persistent northeasterly swell continues to radiate off
lingering low pressure several hundred miles northeast of the
Carolinas. Seas here are 6-7 feet, while south of Hatteras seas
are closer to 2-5 feet. Winds will veer from nerly to serly
through today though remain generally around 10 kt.

LONG TERM /Wed through Sat/...
As of 200 AM Tuesday...

 - Elevated seas mid-week

 - Watching the tropics late-week

Elevated seas continue across the coastal waters mid-week,
especially north of Cape Hatteras, thanks to a persistent
northeasterly long-period swell. Winds will remain relatively light
during this period, though, and range from 5-15kt. Late Thursday
into Friday, we`ll be closely monitoring a potential tropical system
that is forecast to move inland across the Southeast U.S. The latest
guidance keeps this system well west of ENC. However, a strong
gradient east of the system should support a period of moderately
impactful winds and seas. With this forecast update, we`ve increased
winds Thursday night into Friday, and are now showing a period of 15-
25kt south to southeast winds. Recent guidance suggests some 30-35kt
wind gust potential, but this is highly dependent on the track of
the tropical system, so stay tuned. For now the key message is to
plan ahead for gusty winds and building seas, with the impacts
focused on Friday.

&&

.TIDES/COASTAL FLOODING...
As of 200 AM Tuesday...

The coastal flood threat continues for all of coastal North Carolina
for at least one more day as tide levels remain elevated. This
includes the recently added Neuse, Bay, Pamlico, and Pungo Rivers,
where we received reports of multiple roads closed in Belhaven.
Water levels at high tide today will be slightly lower than
yesterday, but could still result in up to a foot of inundation
above ground level. Along and north of Ocracoke, persistent
northeasterly swell from a distant low offshore will continue to
bring minor overwash concerns with maximum inundation around 1-2
feet.

Looking ahead, we`ll continue to closely monitor the track of
Potential Tropical Cyclone #9 as distant coastal impacts could be
felt across a portion of ENC thanks to increasing southerly onshore
winds.

&&

.MHX WATCHES/WARNINGS/ADVISORIES...
NC...Coastal Flood Advisory until 5 PM EDT this afternoon for
     NCZ080-094-194>196-199-203>205.
     Beach Hazards Statement until 8 PM EDT this evening for NCZ203-
     205.
MARINE...Small Craft Advisory until 8 PM EDT Wednesday for AMZ150-152-
     154.

&&

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