Area Forecast Discussion
Issued by NWS Newport/Morehead, NC

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FXUS62 KMHX 230541
AFDMHX

Area Forecast Discussion
National Weather Service Newport/Morehead City NC
141 AM EDT Sat Mar 23 2024

.SYNOPSIS...
A coastal low and cold front will impact the area this weekend.
High pressure builds in early next week. Another coastal low is
possible mid to late next week.

&&

.NEAR TERM /OVERNIGHT/...
As of 8 PM Friday...

**Low pressure system to impact ENC with multiple hazards
 tonight through Sunday**

Forecast in good shape with little changes needed for the
evening update. Light showers continue to lift into ENC with
heavier showers along the coast. Lightning has remained offshore
for the most part where meager instability to around 500 J/kg
currently resides but it has been making a run toward the OBX
and toward the Pamlico Sound. As discussed below, the severe
threat remains low until near daybreak through Saturday morning
when strongest forcing and somewhat better instability builds
into the area.

Previous discussion...An upper level shortwave will move across
the Southeast US through Saturday. At the surface, low pressure
will track northeast from the northern Gulf Coast through the
eastern Carolinas. Guidance is now solidly focused on a surface
low track along the coast of Eastern NC, although there will be
a secondary low that will track inland, which complicates the
forecast some.

The greatest low-level convergence will be focused along the
low that tracks along the coast, and this is still where we
expect the heaviest rainfall to be with this event. Essentially,
this puts most of Eastern NC along and east of HWY 17 in a
solid 2-3" of rain, with 1-2" to the west. Where convection
occurs, max rainfall guidance suggests amounts as high as 4-6"+.
Coming on the heels of a period of very dry conditions, the
area should be able to handle 1-3" of rain. However, where/if
those higher amounts occur, there will be an increased risk of
hydro concerns (small creek, urban, poor drainage, and flash
flooding). Confidence in those higher amounts is low enough to
preclude a Flood Watch, but this potential will be re-evaluated
in later shifts.

Regarding the convective potential, confidence is about the
same as before. As deeper moisture moves in tonight, there will
be a gradual increase in instability, but poor mid-level lapse
rates and only modest boundary layer moisture quality will tend
to keep instability on the low side (<500j/kg) tonight, and
convection will probably tend to be more elevated in nature. For
these reasons, I expect the risk of severe weather to be low
tonight.

On Saturday, the coastal low will shift away from the coast as
a cold front approaches from the west. Widespread rain along the
track of the low will limit daytime heating, and the better
quality moisture will held to our east, along and east of the
departing SFC low. The question, then, is how much destabilization
can occur ahead of the advancing cold front during the day
Saturday. HREF probabilistic guidance gives a 60-80% chance of
MLCAPE exceeding 500 j/kg, while the SREF only gives about a
30-50% chance. For any severe weather risk to materialize, we
will need some heating to help offset the lack of better quality
moisture. If sufficient heating/destabilization can occur,
there would be an increased risk of deep convection with
gusty/damaging winds the primary risk. A tornado cannot be ruled
out, but the flow will be trending more unidirectional,
limiting this risk. SPC has continued with a "Marginal" risk for
our area on Saturday, and this seems perfectly reasonable given
the potential outlined above. The key message here is that it
is not a high- confidence risk.

A wind advisory is in effect from Down East Carteret Nward to
Oregon Inlet during the "prefrontal" phase of the storm; Serly
winds 20-30mph with gusts up to 50mph.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY/...
As of 1545 Friday...

**Low pressure system to impact ENC with multiple hazards
 tonight through Sunday**

The upper level shortwave shifts offshore Saturday night. At
the surface, low pressure will track northeast from the northern
Gulf Coast through the eastern Carolinas. Guidance is now
solidly focused on a surface low track along the coast of
Eastern NC, although there will be a secondary low that will
track inland, which complicates the forecast some.

Behind the front, a strong northerly surge of wind will develop
by late afternoon into the evening hours Saturday. The strong
northerly winds will last well into Sunday, with widespread
gusts of 30-45 mph expected. Along the Outer Banks, gusts as
high as 45-50 mph are possible. Additional wind headlines will
likely be needed later to cover the strong northerly winds.
With the strong winds comes an increased risk of coastal
impacts. Please see the "Coastal Flood" section of the AFD for
additional details.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
As of 420 AM Fri...

High pressure builds south into the Carolinas early next week
as the weekend low departs. However, coastal impacts will likely
continue especially across the northern Outer Banks with
persistent northerly flow as low pressure lingers offshore.
Attention turns to yet another cold front and attendant coastal
low late next week, although as expected nearly a week out
details on the system`s evolution are murky. Still, if realized
another round of heavy rainfall, strong winds and coastal
impacts are possible.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM /through 06z Sunday/...
As of 130 AM Saturday...

KEY MESSAGES

1) Increased risk of IFR conditions through Saturday morning

2) Widespread RA and a few TSRA through Saturday

3) LLWS impacts through Saturday morning

4) Northerly wind shift along a cold front Saturday afternoon

FORECAST DETAILS

Low pressure will move northeast along the coast of South Carolina
and North Carolina overnight, then shift offshore during the day
Saturday. Along and ahead of the low, widespread RA will impact
Eastern NC through Saturday morning. A few TSRA will be possible as
well, although confidence at any one TAF site is too low for a
mention. Amendments will be made overnight if confidence increases.
A cold front will then move east across the area Saturday afternoon,
with a continued risk of SHRA and TSRA. A notable northerly wind
shift will occur behind the front. Gusty winds will occur both ahead
of, and behind, the front. Peak gusts of 20-35kt can be expected.
Lastly, low CIGs will accompany the low pressure area and the cold
front, with IFR CIGs expected at times. IFR CIGs may improve to MVFR
for a time Saturday, especially after the low shifts offshore. Prior
to the low moving offshore, there will also continue to be LLWS
impacts thanks to a strong south to southeasterly low-level jet.

LONG TERM /Saturday night through Monday/...
As of 425 AM Fri...A coastal low will impact Eastern NC
through Sunday with an increased risk of sub-VFR conditions,
possible TSRA, and strong winds. Wind gusts of 25-40kt are
likely during this time, especially across the Outer Banks.
Widespread +RA and reduced VIS can be expected as well.
Conditions will improve Sunday into Monday, but strong northerly
winds will persist particularly for coastal locales.

&&

.MARINE...
SHORT TERM /through Tonight/...
As of 1540 Friday...Benign boating conditions will be short-
lived as a coastal low moves northeast through area waters late
tonight into tomorrow, with lingering impacts lasting well into
next week. After sunset tonight, southeasterly winds of 25-35 kt
with frequent higher gusts are expected to overspread all
coastal waters and sounds. Seas will be extremely quick to
respond, with the highest waters across Raleigh Bay with wave
heights reaching 10-15 feet by Sat morning.

All existing Gale Watches have been upgraded to Gale Warnings
this morning, with the exception of the Pamlico/Pungo river
where a SCA is in effect.

Expecting showers and thunderstorms, some of which may be
strong to severe with a threat for waterspouts especially in
cells along the warm front, moving from S to N through the short
term.

LONG TERM /Saturday through Monday/...
As of 440 AM Fri...Dangerous marine conditions carry through
the weekend and into Monday. As low lifts across the region on
Saturday, winds will weaken slightly as winds veer northerly. By
Sun morning, strong winds will return but this time due north
at around 30-35 kt with higher gusts and a few Storm force gusts
possible over the far outer central waters. These winds will
this time focus highest waves north of Cape Hatteras with seas
of 12-15 feet, although widespread 6+ foot seas will still be
ongoing across all waters through Monday.

&&

.TIDES/COASTAL FLOODING...
As of 4 PM Friday...The Coastal Flood Advisory remains in effect
through Saturday for ocean side locations south of Oregon Inlet
and locations along the northern and western Pamlico Sound. A
Coastal Flood Watch has been issued from late Saturday night
though late Monday night for ocean side locations north of Cape
Hatteras and southern portions of the Pamlico Sound, Core Sound
and lower Neuse River.

A strong, complex low pressure system will impact the area this
weekend into early next week. Still some uncertainty with
respect to the track, and strength, of the low, but based on the
latest guidance, we expect minor to moderate coastal flooding,
both soundside and oceanside, with ocean overwash, rough surf
and beach erosion also expected. Impacts could begin as early as
tonight, then peak Saturday and Sunday. Impacts are expected to
linger into Monday.

Areas vulnerable to 20-25 kt sustained SE winds (locations up
the Neuse, Bay, Pamlico, Pungo Rivers, Bogue Sound and oceanside
areas from N Topsail Beach up towards Oregon Inlet) will likely
see minor coastal flooding Friday night into Saturday morning.
Then winds will shift to the N Saturday night through Sunday
into the 25-35 kt range with higher gusts, with the coastal
flood threat shifting to soundside areas adjacent to the S/E
Pamlico Sound and oceanside areas from Duck to Cape Lookout.
Troublesome area on the northern end of Ocracoke Island may be
impacted with ocean overwash on Hwy 12...along with other
oceanside areas with vulnerable dune structure. Stay tuned for
updates on this potential.

A High Surf Advisory is in effect for all coastal zones south of
Oregon Inlet for much of Saturday. Resultant ocean overwash
across Ocracoke Island will likely cause flooding across Highway
12 as early as tonight.

&&

.MHX WATCHES/WARNINGS/ADVISORIES...
NC...Coastal Flood Advisory from 5 AM early this morning to 6 PM
     EDT this evening for NCZ047-080-081-094-195-199.
     Coastal Flood Watch from late tonight through late Monday
     night for NCZ094-194-196-203>205.
     High Surf Advisory from 8 AM this morning to 6 PM EDT this
     evening for NCZ195-199.
     Coastal Flood Advisory until 8 PM EDT this evening for NCZ196-
     205.
     Wind Advisory until 2 PM EDT this afternoon for NCZ196-204-205.
     High Surf Advisory from 5 AM early this morning to 11 PM EDT
     this evening for NCZ196-204.
     Coastal Flood Advisory until 11 PM EDT this evening for NCZ204.
     High Surf Advisory from 8 AM this morning to 8 PM EDT this
     evening for NCZ205.
MARINE...Gale Warning from 11 PM this evening to 5 PM EDT Sunday for
     AMZ131-230.
     Gale Warning until 2 AM EDT Monday for AMZ135.
     Small Craft Advisory until 11 PM EDT Sunday for AMZ136.
     Gale Warning from 5 AM to 2 PM EDT Sunday for AMZ137.
     Gale Warning from 8 AM this morning to 2 AM EDT Monday for
     AMZ150.
     Gale Warning until 5 AM EDT Monday for AMZ152-154-156.
     Gale Warning until 2 AM EDT Monday for AMZ158.
     Gale Warning from 5 AM early this morning to 11 PM EDT Sunday
     for AMZ231.

&&

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


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