-- Discussion containing changed information from previous version are highlighted. --
818
FXUS62 KMHX 182013
AFDMHX

Area Forecast Discussion
National Weather Service Newport/Morehead City NC
413 PM EDT Wed Sep 18 2024

.SYNOPSIS...
A weak cold front will move into eastern NC late today and cross
the region Thursday producing unsettled conditions across
eastern NC. High pressure will build over the area over the
weekend into early next week with mostly fair weather conditions
expected.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
-- Changed Discussion --
As of 3:30 PM Wednesday...Upper troughing persists with the
remnants of PTC #8 over far western NC and SC. Off the VA/NC
coast, a secondary low is gradually moving northeast. A stalled
boundary across ENC will begin moving eastward this evening,
which could spark some widely scattered showers and some
isolated thunderstorms across the CWA. The best chance for this
activity will be across far western and northern counties (west
of Highway 70 and north of Highway 17). A slight chance (15-20%) of
widely scattered showers will persist overnight with lows in the
upper 60s to low 70s.

Light winds and saturated soils will prime the environment for
another round of fog and low stratus beginning around or just
after midnight. The coastal plain will likely experience the
most impactful fog with visibility down to a mile or less at
times.
-- End Changed Discussion --

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
-- Changed Discussion --
As of 3:30 PM Wednesday...The mid/upper trough will deepen as
it moves slightly to the east tomorrow. At the surface, two low
pressure systems will be offshore: one off the SC/NC coast and
another near DE/MA. Guidance shows a surface low developing over
eastern North Carolina as the base of the trough swings through,
which will be the main forcing mechanism for any shower or
thunderstorm activity. Chances will increase through the day and
peak in the afternoon (45-50% for the coastal plain, 25-40% for
the beaches). Modest instability (MLCAPE 500-1500 J/kg) could
support a few stronger thunderstorms, but these would be
isolated in nature.
-- End Changed Discussion --

&&

.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
As of 300 AM Wednesday...Mid/upper level trough lingering over
the region through the end of the work week brings daily precip
chances through Friday, and ridging starts moving in from the
north and west through the weekend as a low spins up well
offshore confining precip chances generally east of hwy 17
through the remainder of the long term period. Seasonable (or
just below) temps through the period.

Thursday:
Mid and upper level trough starts shifting eastward over ENC
Thursday and its surface counterpart low pressure system starts
to strengthen offshore of the delmarva peninsula and NJ. We will
have enough mid and upper level forcing directly above us paired
with PWATs near 1.75" and CAPEs near 500-750 J/kg for scattered
showers and thunderstorms (PoPs near 50%). Current expectation
is for most of the convection to remain thunder free with lower
instability, but if CAPEs start trending higher thunderstorm
coverage would increase as a result. Deep Layer Shear generally
below 20 kts will limit the severe potential and storms aren`t
expected to become tall enough for damaging microbursts. If
there is any hazard to be mindful of Thursday, it would be slow
to moderate storm motions allowing for rainfall to accumulate
over areas that already have saturated soils from the recent
rainfall. Northerly flow would allow the sea breeze to remain
close to the coast (if it develops at all), which could cause
problems for Carteret County as the sea breeze would provide
additional stationary forcing. However this a low probability
outcome and we will have a better idea once more hi-res guidance
comes in. Showers and Tstorms will scour our with the loss of
daytime heating Thursday evening/night.

Friday:
Mid/upper level trough starts moving offshore to the east Friday
PM as high pressure starts moving in from the west. Decreased
forcing and a drop in PWATs will lead to clearing skies and
precip chances highest offshore and along OBX. Thunder possible
offshore, but expecting just showers over land Friday. Rain
chances east of hwy 17 are 20-30% Friday with drier condition
expected for the coastal plain. Low continues meandering off the
delmarva coast, sandwiched between ridging from all directions.

The Weekend:
Low precip chances, 10-20% for offshore and OBX, as low
continues meandering to our east. Substantial ridging builds in
over ENC from the north, which provides a stronger pressure
gradient through the weekend and early next week. This will
result in a slight uptick in winds, but skies are expected to
remain partly/mostly cloudy through the weekend.

Monday-Tuesday:
Ridging and drier conditions continue through Monday, and
Tuesday the high shifts offshore reintroducing slight chances of
rain again.

&&

.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
-- Changed Discussion --
SHORT TERM /through Tonight/...
As of 1:45 PM Wednesday...All TAF sites have finally returned
to VFR as of this afternoon, but ample low level moisture has
allowed low clouds to stick around. Tonight will be a very
similar story to last night with fog and low stratus likely
developing after midnight. The inner coastal plain terminals
(PGV and ISO) have the greatest chance of seeing fog and low
stratus, but these conditions are on the table for all
terminals.

My thinking is that low stratus will develop after midnight and
drop ceilings to low-end MVFR to IFR. As we progress towards
Thursday morning, ceilings and visibilities will likely bottom
out between 8-13Z with LIFR (and possibly VLIFR) visibilities
possible. As the sun comes up, conditions will be slow to
improve. MVFR ceilings will likely stick around for all TAF
sites through the end of the period when chances for afternoon
showers and thunderstorms come into play (45-50%).

LONG TERM /Thursday through Sunday/...
As of 400 AM Wednesday...Continued unsettled weather will bring
a chance for brief/occasional sub- VFR conditions across ENC
Thursday due to widely scattered to scattered mainly afternoon
and early evening showers and thunderstorms. Friday onward VFR
conditions expected, although Saturday morning could see some
fog as skies clear and winds calm.
-- End Changed Discussion --

&&

.MARINE...
-- Changed Discussion --
SHORT TERM /Through Thursday/...
As of 4 PM Wednesday...Sub-SCA conditions persist through the
period. 3-5 ft seas will decrease to 2-4 ft by Thursday morning.
Winds will remain around 10 kt or less through the period with
variable wind directions becoming northwesterly by late tonight
and northerly by Thursday afternoon.

LONG TERM /Friday through Sunday/...
As of 400 AM Wednesday...Northerly winds increase to 10-15 kt
Fri then become 15-20 kt Sat. and 20-25 kt Sunday. There is a
30-40% chance of seeing gale force gusts for the central and
northern waters and the Pamlico Sound Sunday into early Monday.
The strength of the winds depends on the position and strength
of the low developing offshore to our northeast, and how strong
the ridging pushing in from the north is. Seas will be 2-4 ft
through Friday, then increase to 3-6 ft Saturday and 4-7 ft
Sunday as gusty winds + the low offshore results in higher
swell.
-- End Changed Discussion --

&&

.TIDES/COASTAL FLOODING...
-- Changed Discussion --
As of 4 PM Wednesday...Coastal flooding will continue to be a
risk given the higher than normal astronomical tide cycle. The
Coastal Flood Advisory for Ocracoke has been extended and new
Coastal Flood Advisories have been issued for all remaining
zones, which are currently set to last through Saturday.
-- End Changed Discussion --

&&

.MHX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
NC...Coastal Flood Advisory until 10 PM EDT Saturday for NCZ195-196-
     199-203>205.
     Beach Hazards Statement through Thursday evening for NCZ196-
     203>205.
MARINE...None.
-- End Changed Discussion --

&&

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