Area Forecast Discussion
Issued by NWS Newport/Morehead, NC

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS62 KMHX 230823
AFDMHX

Area Forecast Discussion
National Weather Service Newport/Morehead City NC
423 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 /TODAY/...
As of 345 AM Saturday...

Based on radar and surface obs, an area of low pressure appears
to be located near Wilmington as of this writing. A warm front
arcs northeast up along the coast of NC, and roughly stretches
from Wilmington to New Bern to Nags Head. Along and south of
that boundary is where the warmest airmass is, and is where
winds have been the strongest thus far. Along the coast, winds
have been gusting as high as 30-45 mph. So far, the peak wind
gust measured over land has been 49 mph at the Hatteras Airport
(KHSE). That occurred around 2am. North of the warm front, less
mixing is occurring, and winds are relatively light. The surface
low will continue to lift NE through ENC over the next several
hours, with the strongest winds remaining focused along and
south of where the warm front resides. Short-term guidance has
trended a bit higher with the peak southerly gusts along the
track of the SFC low this morning, and based on SFC obs, this
seems very reasonable. Because of this, I nudged winds up
through the morning hours.

Regional radar shows widespread moderate to occasionally heavy
rain ongoing along and north of the SFC low at this time, and
this will continue through the early morning hours. Near the
low, itself, there has been enough low-level moistening to
support weak instability and an area of deeper convection,
especially from Wilmington south out over the Atlantic. As the
low continues to move NE, so will the plume of better low-level
moisture and improved instability. What I suspect will happen is
that a band of thunderstorms will continue to move northeast
with the low, clipping a portion of ENC, especially along and
east of HWY 17. It still appears that instability will be less
than supportive of a greater severe weather risk, but we`ll
continue to message a conditional risk through about mid-morning
or so. The main threat will be areas of enhanced wind gusts and
possibly some minor wind damage. A brief tornado cannot be
ruled out right along the immediate coast, but overall, the risk
of severe weather still remains low. In addition to the severe
weather risk, there remains the potential for minor hydro issues
where the heaviest rainfall occurs. This should be focused
along the coast where the heaviest rain has fallen thus far, and
where additional rainfall amounts will be the highest.

In the wake of the low, a cold front will eventually push east
across ENC this afternoon. Once again, instability is forecast
to be on the low side ahead of the front, but perhaps a stronger
core with gusty winds could develop. With a more veered flow by
the afternoon, the main risk should be gusty winds, with even
less of a tornado threat compared to this morning.

&&

.SHORT TERM /TONIGHT THROUGH SUNDAY/...
As of 345 AM Saturday...

The main impact in this period will be a long-duration
northerly wind event as today`s cold front moves offshore, and
as low pressure deepens out in the Atlantic. This will setup a
tightening pressure gradient along the coast of the Carolinas
through Sunday. Additionally, modest CAA will support steepening
lapse rates and improved mixing compared to today, tapping into
a strengthening northerly LLJ. While winds aloft aren`t
expected to be as strong as today, the enhanced mixing will
likely lead to stronger winds Saturday night-Sunday for many
areas. Probability guidance continues to give a moderate to high
chance (50-70%) of 45-50 mph winds occurring along much of the
Outer Banks, especially from Duck to Cape Lookout. With this in
mind, we have extended the Wind Advisory to include all of the
Northern OBX now, and have extended it out in time through
Sunday evening. It`s possible further extensions in time will be
needed, although mixing should be waning some by Sunday night,
which should support winds falling below 45 mph. Away from the
OBX, it will be breezy during this time as well, but winds
should stay just shy of advisory criteria.

Temperatures will trend notably cooler as well, especially
across the NRN OBX where the wind will be advecting off the
cooler shelf waters for an extended period of time. There, temps
may struggle to get out of the low-50s on Sunday.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
As of 345 AM Sat...Canadian high pressure extends southward
over the eastern seaboard Sunday night and remains in control
into Tuesday. This weekend`s low will linger offshore, keeping
elevated northerly winds in place along the Outer Banks into
early next week and promoting ongoing coastal flooding and beach
hazard concerns for areas particularly north of Cape Hatteras -
see the TIDES/COASTAL FLOOD section for details.

Next round of inclement weather will be mid to late week.
Deepening low pressure over the central plains in response to a
negatively tilted shortwave trough will drag a slow-moving cold
front towards the Carolinas, eventually stalling over the area.
The frontal boundary will likely have an increase of clouds and
some modest shower activity although best lift will be displaced
well to our west. Greater concern is a second s/w trough
forecast to pivot across the Gulf states and become negatively
tilted, which will drive robust cyclogenesis along the surface
boundary.

The devil remains in the details. Ensemble guidance continues to
trend towards the stalled front/coastal low solution (although
a few members still advertise a clean frontal passage), but
considerable spread in timing and track of the system remain.
Still, another round of heavy rainfall, strong winds and coastal
impacts are possible by week`s end.

&&

.AVIATION /07Z 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 /Sunday night through Wednesday/...
As of 345 AM Sat...Flight conditions will improve late Sunday
through Tuesday as high pressure builds in from the north, but
strong northerly winds will persist particularly for coastal
locales.

&&

.MARINE...
SHORT TERM /through Sunday/...
As of 345 AM Saturday...

**Dangerous marine conditions to continue for an extended
 period of time**

Low pressure will move northeast along the coast of ENC, with
strong southerly winds occurring ahead of it. Over the warmer
waters south of Cape Hatteras, winds have already been gusting
over 40kt, and this will continue for several more hours. At the
height of the winds, a few gusts to near storm force cannot be
ruled out for those waters. Elsewhere, 25-35kt winds will be
common through mid to late morning. Over the coastal waters,
buoys are showing seas of 12ft+ already, and these will continue
to build to as high as 15-20ft this morning. North of Cape
Hatteras, seas will top out in the 10-15 ft range. Wave guidance
has been struggling with the building waves in the southerly
flow, so I went above guidance through this morning. I also
increased winds some, based on trends in obs over the past
several hours.

Winds will lay down some for a few hours this afternoon, but
will quickly rebuild out of the north in the wake of a cold
front passage. This will then shift the greatest wind and wave
impacts to waters north of Cape Hatteras. Widespread gale-force
winds will occur with this northerly surge, even over the inland
rivers and sounds.

LONG TERM /Sunday night through Wednesday/...
As of 355 AM Sat...Dangerous marine conditions will continue
through the long term period. Canadian high pressure builds over
the Carolinas from the north, but with low pressure continuing
to meander offshore strong northeasterly flow will be slow to
ease. Strongest winds will be Sunday night with gusts up to 40
kt especially across portions of Raleigh Bay, but 25+ kt wind
gusts will plague area waters through Monday night.

The persistent northerly fetch will keep seas dangerously high,
particularly north of Cape Hatteras. Swell of 10-15 ft with
periods of 13-14 seconds will persist through Tuesday night
here, while across Raleigh Bay, seas will be closer to 8-12
feet.

&&

.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 until 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 8 PM EDT Monday for NCZ196-204-205.
     High Surf Advisory until 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 AMZ135-158.
     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 11 PM EDT Sunday for AMZ231.

&&

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


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.