-- Discussion containing changed information from previous version are highlighted. --
168
FXUS62 KMHX 180040
AFDMHX

Area Forecast Discussion
National Weather Service Newport/Morehead City NC
840 PM EDT Tue Sep 17 2024

.SYNOPSIS...
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Troughing will remain over the Eastern Seaboard through next
week and keep unsettled conditions across ENC.
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&&

.NEAR TERM /OVERNIGHT/...
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As of 800 PM Tuesday...

 - Monitoring potential for dense fog overnight

Satellite imagery this evening reveals a well-defined upper
level low spinning over the Upstate of SC, with a surface low
analyzed near Columbia, SC. North of the surface low, a
convergence boundary/surface front stretches west to east
across the length of northern NC. Along that boundary is where
the best overlap of deep moisture, lift, and instability
resides, and this is where persistent shower and thunderstorm
activity has been. Locally, this boundary stretches across the
far NRN OBX where shower activity continues. Recently, radar
trends have shown a slow northward progression of the showers,
and based on short-term guidance, this trend should continue.
Until the boundary lifts fully out of the area, though, there
will still remain a risk of showers. The previous forecast
handles this well, so no substantial changes were needed to the
forecast.

Recent short-term guidance continues to show a decent signal
for fog overnight, especially across the northwestern half of
ENC. The only change made to this part of the forecast was to
extend the fog risk further south and east towards the southern
coastal areas based on forecast soundings and a favorable setup
for fog.

PREVIOUS DISCUSSION...The remnants of PTC #8 are now well
inland over SC. An occluded front is draped across NC from west
to east and a surface low has formed along the periphery of this
boundary, which continues to support shower development mainly
north of Highway 70. Activity should wane as we move into the
evening hours due to dry air entrainment in the upper levels.

Given the saturated soils, light winds, and lack of overnight
cloud cover, the environment is primed to support the
development of fog and low stratus, especially over the inner
coastal plain. Lows will drop to the low to mid 60s across the
coastal plain and near 70 along the beaches.

The risk of coastal flooding along the inland rivers will wane
today, but will persist along coastal locations - see the
TIDES/COASTAL FLOOD section for more details.
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&&

.SHORT TERM /WEDNESDAY/...
As of 4:30 PM Tuesday...The upper trough will remain dominant
over the eastern US. At the surface, a warm front will be draped
across ENC in association with a series of lows across the
southeastern US. The greatest chance (15-25%) for showers and
thunderstorms associated with this boundary will be across the
inner coastal plain tomorrow afternoon. The greatest instability
will be displaced from the area most likely to see rainfall, so
the severe threat will be low. However, a stronger thunderstorm
can`t be ruled out.

It will be warm and muggy with highs in the mid-80s and
dewpoints in the low 70s.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
As of 300 AM Tue...Unsettled weather will continue through the
period as persistent mid/upper level troughing remains over the
Eastern Seaboard. This will result in daily chances for showers
and thunderstorms across the region into next weekend.

Thursday 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 remains uncertainty with the forecast as the
upper trough over the Eastern Seaboard is forecast to cutoff
into an upper low as upper ridging builds across the Northeast.
As is typical with upper lows, spread in timing and depth of the
feature remains large and forecast confidence remains below
average.

Either way, daily chances for showers and thunderstorms,
especially tied to the diurnal cycle in the afternoons to early
evenings is expected across the area into the weekend. Continued
onshore flow will keep clouds around the region while temps
remain at or below avg.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
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SHORT TERM /through 00z Thursday/...
As of 800 PM Tuesday...

 - Monitoring potential for BR/FG/low CIGs tonight into
   Wednesday AM

Light winds, clearing skies, and residual low-level moisture
appears supportive of the development of BR/FG tonight. The
previous TAFs already had this potential covered, but I made
some changes to lower the VIS/CIG forecast based on a continued
good signal in model guidance, and based on a favorable setup
for BR/FG. Of note, ensemble guidance shows a decent signal for
LIFR conditions across portions of the coastal plain, and this
will be something to monitor through the night as it would have
a greater impact to aviation. During the morning hours on
Wednesday, VIS and CIGs are expected to improve, although
improvement may tend to be slower than normal, especially
inland.

During the day Wednesday, a modestly moist, and unstable,
airmass plus an approaching surface low may allow isolated SHRA
and TSRA to develop. Because of weaker lift for most of the day,
confidence is low at any one TAF site, and I opted to leave out
any mention of SHRA or TSRA for now. Where SHRA/TSRA occur,
there would be a risk of sub-VFR conditions.

LONG TERM /Wednesday night through Sunday/...
As of 300 AM Tue...Continued unsettled weather will bring a
chance for brief/occasional sub-VFR conditions across ENC daily
due to widely scattered to scattered mainly afternoon and early
evening showers and thunderstorms.
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&&

.MARINE...
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SHORT TERM /Through Wednesday/...
As of 3:30 PM Tuesday...Dangerous marine conditions persist due
to lingering 6-7 foot seas from former PTC #8. SCAs are in place
for all coastal waters until 4 AM Wednesday and seas will
decrease to 3-5 ft tomorrow. Winds will remain at 10 kt or
less through the period.

LONG TERM /Wednesday night through Sunday/...
As of 300 AM Tue...Winds should remain generally light /10 kt
or less/ through Wed with the flow W-SW Wed, and N on Thu.
Northerly winds increase to 10-15 kt Fri then become NE 15-20 kt
Sat. Seas will be 3-5 ft Wed, then 2-4 ft Thu and Fri. Seas
could build to 4-6 ft Sat due to the increased NE winds.
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&&

.TIDES/COASTAL FLOODING...
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As of 830 PM Tuesday...Coastal flooding will continue to be a
risk given the higher than normal astronomical tide cycle. Based
on continued reports of flooding, and the higher water levels,
we have extended the Coastal Flood Advisories out through
Wednesday morning`s high tide. The risk of minor coastal
flooding may continue through the week as we remain in a higher
than normal astronomical tide cycle.
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&&

.MHX WATCHES/WARNINGS/ADVISORIES...
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NC...Coastal Flood Advisory until 10 PM EDT this evening for NCZ195-
     196-199-204.
     Beach Hazards Statement from 8 AM EDT Wednesday through
     Wednesday evening for NCZ196-203>205.
MARINE...Small Craft Advisory until 4 AM EDT Wednesday for AMZ150-152-
     154.
     Small Craft Advisory until 10 PM EDT this evening for AMZ156-
     158.
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&&

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