-- Discussion containing changed information from previous version are highlighted. --
920
FXUS62 KMHX 251135
AFDMHX

Area Forecast Discussion
National Weather Service Newport/Morehead City NC
735 AM EDT Wed Sep 25 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. TC Helene will pass through the interior Southeast US
and bring a period of mostly minor impacts to ENC on Friday.

&&

.NEAR TERM /TODAY/...
-- Changed Discussion --
As of 7 AM Wednesday...The upper ridge off the east coast will
continue moving further offshore today. A positively tiled upper
trough across the Mississippi River Valley will deepen and
become cut off. At the surface, a warm front is draped roughly
along Highway 70 has continued to spark isolated showers across
the area. This activity is expected to continue and become more
widespread as the boundary lifts north today.

Given that showers and storms are expected to be scattered, PoPs
have been capped at chance, except for near and along the NOBX where
it should remain mostly dry today. 1000-1500 J/kg of MLCAPE will be
more than enough instability to fuel a few thunderstorms, some of
which could be strong to severe. With PWATs around 1.5-2"+ and 25-30
kt of deep layer shear, organized multicells with gusty winds
and heavy rainfall rates are probable.
-- End Changed Discussion --

&&

.SHORT TERM /TONIGHT/...
As of 3 AM Wed...PoPs quickly drop off after sunset but cloud
cover will stick around overnight, which will support mild low
temps around 70.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
As of 4 AM Wed...

Thursday...Onshore serly flow will bring cont moistening of the
bndry layer, and there will be iso to sct showers as weak WAA
occurs. Have a 20-30% chc of rain in the fcst for these showers.
QPF amts will be light, generally less than a tenth of an inch.
Shower chances should diminish during the evening, but by
sunrise, approaching heavier showers from the west emanating
from the outer bands of TC Helene may begin impinging on the
swrn coastal plain counties. Warm and humid with highs in the
mid 80s Thu only cool to the mid 70s on Thu night.

Friday/Friday Night...The main item of interest will be the
impacts from TC Helene, which the center of the storm will be
moving through GA and then into the TN Valley. With the large
size of the system, some outer rain bands will be propagating
through ENC during the day. 25/00z deterministic and ensemble
guidance in good agreement with the track of the system. Strong
moisture advection east of the center should allow a plume of
tropical moisture to quickly overspread the coastal Carolinas
throughout the day from w to e. 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, some of which may become
severe and contain a few tornadoes. MLCAPE vals inc to aoa
1,500 J/KG with plume of mid/upr 70s TD`s overspreading the
region. Strong backing of sfc winds to the SE will produce
enhanced low lvl helicity, and a favorable environment for a
tornado or two will develop. While quick- hitting, guidance has
been showing a consistent signal for a brief period of heavy
rain and localized flooding, though the good news is the band or
bands of heavy rain will be progressing eastward fairly
quickly, with rain ending as early as mid afternoon for many
areas save for the OBX, and all areas by day`s end. Attm, 0.75"
to 1.00" are forecast, with locally higher amounts in heavier
cells. Breezy conditions will be present as well, with sserly
breezes gusting to 20-25 mph inland, with 25-30 mph close to the
coast. Quick drying with all rain ending and winds diminishing
rapidly and becoming swrly Fri evening, with temps still muggy
in the low 70s.

Saturday...Mainly dry with subsidence in place behind the
system, and upr low pres well west of ENC. Warm and humid
continues with swrly flow, and highs in the mid 80s.

Sunday through Tuesday...Aforementioned upr low migrates slowly
eastward, with chances for showers each day, with perhaps a
surface low developing near or over ENC. Have capped pops at 30%
attm due to uncertainty on synoptic and mesoscale features this
period. Temps will cont to near or slightly above climo, with
highs in the low/mid 80s to 60s for lows.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
SHORT TERM /through today/...
As of 7 AM Wednesday...A stationary boundary draped roughly
along Highway 70 will continue to support isolated showers
this morning but will become more widespread later today.
There is enough moisture, instability, and deep shear for some
strong to severe storms with gusty winds and heavy rain.
Activity will decrease after sunset and flight cats should
remain predominantly VFR until early tomorrow morning when the
next round of fog and low stratus will be present.

LONG TERM /Thu through Sun/...
As of 4 AM Wed...A few iso to sct showers will dot the region
on Thu with onshore serly light winds. On 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 end by late Fri afternoon into
evening as dry air moves in behind the system.
-- End Changed Discussion --

&&

.MARINE...
-- Changed Discussion --
SHORT TERM /Through tonight/...
As of 4 AM Wednesday...Current obs show 5-6 ft seas at 11-12
seconds north of Ocracoke Inlet and 3-5 ft at 11-12 seconds to
the south. SCAs remain in effect for the coastal waters from
Duck to Ocracoke Inlet with little change expected during the
period. The waters south of Ocracoke Inlet will slowly build to
6 ft by Thursday morning, at which time a SCA will be in effect
for those waters. Light (< 10 kt) southeasterly winds will
increase to 10-15 kt south of Cape Hatteras today.

LONG TERM /Thu through Sun/...
As of 4 AM Wed...Building seas occur on Thu ahead of TC Helene
well south and west of ENC, and have added the remaining ctrl
and srn waters into the SCA suite, with seas building to 6+ ft
Thu morning. On Fri, gradient inc to 20-25 kt sustained and
gusts to 30 kt for the coastal waters, esp ctrl and srn waters,
and seas build to 7-10 ft with the sserly winds. Attm it appears
winds will remain below gale/trop storm force, though the large
wind field will cont the high seas into Fri evening. Winds
quickly diminish and turn swrly Fri night and cont into Sat with
seas subsiding to below SCA by Sat afternoon.
-- End Changed Discussion --

&&

.TIDES/COASTAL FLOODING...
As of 4 AM Wed...The coastal flood threat continues for all of
coastal North Carolina through today as tide levels remain
elevated. This includes the added Neuse, Bay, Pamlico, and Pungo
Rivers, where waters in Belhaven have only recently receded.
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
TC Helene as distant coastal impacts could be felt across a
portion of ENC on Fri into Fri evening thanks to southerly
onshore winds and large waves.

&&

.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 through this evening for NCZ203-205.
MARINE...Small Craft Advisory until 2 PM EDT Saturday for AMZ150-152-
     154.
     Small Craft Advisory from 10 AM Thursday to 2 PM EDT Saturday
     for AMZ156-158.

&&

$$
SYNOPSIS...MHX
NEAR TERM...OJC
SHORT TERM...OJC
LONG TERM...TL
AVIATION...TL/OJC
MARINE...TL/OJC
TIDES/COASTAL FLOODING...MHX