487
FXUS62 KMHX 181122
AFDMHX

Area Forecast Discussion
National Weather Service Newport/Morehead City NC
722 AM EDT Mon Aug 18 2025

.SYNOPSIS...
A cold front will bring chances of scattered showers and
thunderstorms to the area today, which will be capable of
producing heavy rain and isolated flooding. Hurricane Erin is
forecast to pass offshore late Wednesday/early Thursday with
significant coastal impacts expected, especially along the Outer
Banks.

&&

.NEAR TERM /TODAY/...
As of 2:30 AM Monday...

Key Messages:

- Scattered showers and thunderstorms this afternoon/evening may
produce heavy rainfall and isolated flooding

- Heat indices could reach 100-105, especially south of Highway 70

Aloft, a mid-level ridge is positioned over the Ohio River Valley
with a negatively tilted trough pivoting across southeast Canada. An
east/west oriented surface cold front is currently draped across
Kentucky, West Virginia, and Virginia and will move south today
ahead of an embedded mid-level shortwave trough. Deeper moisture
will pool along this boundary, causing a surge in PWATs to 2.25-
2.75". This boundary, as well as diurnal sea/river/sound breezes,
will provide ample lift to support scattered showers and
thunderstorms this afternoon and evening. Instability will be
plentiful with MLCAPE on the order of 1500-3000 J/kg, but shear
will be slim to none, which will decrease the severe threat but
increase the concern for slow moving cells and the potential for
localized flooding. Highest PoPs are relegated to areas away
from the immediate coast with QPF of 0.5-1". The HREF shows
some signal for areas generally along and west of Highway 17 to
reach 1"/hr rain rates. It should also be noted that the LPMM
shows a swath of 2-3" in this same area with localized higher
amounts of 3-5" where stronger and/or training cells develop.

Highs will reach the low-90s across the coastal plain and mid- to
upper-80s along the Outer Banks. Pairing these hot temps with
dewpoints in the 70s will generate heat indices ranging from 100-105
across the coastal plain, especially south of Highway 70.

&&

.SHORT TERM /TONIGHT/...
As of 2:50 AM Monday...

PoPs will diminish after sunset but low stratus will overspread the
area during the overnight hours. There`s also potential for fog,
especially for areas that receive rain today and are able to
decouple overnight. Lows will drop to the low- to mid- 70s area
wide.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
As of 2 AM Mon...

Key Messages:

 - Mainly dry through Wednesday as high pres dominates.

 - Hurricane Erin, which is still forecast to remain offshore,
   will make its closest pass Wednesday night into Thursday,
   with significant coastal impacts expected.

Tuesday...Erly to nerly flow will cont, and seasonably hot
temps prevail. Highs expected 85-90 interior with low/mid 80s on
the OBX. Diurnal afternoon seabreeze showers are possible
(30-40%) with some widely sct thunder potential (15-25%) as
well.

Wednesday...Another day of sct seabreeze showers possible as
weak onshore flow cont, though subsidence well out ahead of
Hurricane Erin will keep chances in the 15-25% range. Breezy
nerly winds develop as gradient inc between approaching Erin and
high pres anchored to the north. Wind gusts in the 15-25 mph
range interior to 20-30 mph coastal areas.

Wednesday Night through Thursday...Core of Hurricane Erin is
forecast to remain offshore but make its closest pass to our
coast Wednesday night into early Thursday. The impacts from Erin
are expected to be confined to marine and coastal interests,
but with a slight westward trend in the track over the past 24
hours, confidence in hazardous conditions has increased (see the
TIDES/COASTAL FLOODING section for details). If the track were
to shift slightly more westward, there is potential for some of
the mainland zones west of the OBX to see some tropical storm
force winds. Outer rain bands will afflict mainly the OBX zones
where likelies are now fcst (60-70%) while the mainland zones
will be more sct in nature (30-50%).

Friday through Sunday...Some lingering coastal impacts still
possible into Fri as large back swell from departing Erin keeps
waves high on the OBX. Sensible weather impacts very limited as
high pres builds. The high may break down some by the weekend,
esp the second half of the weekend as next trough/front inc
shower chances.

&&

.AVIATION /11Z MONDAY THROUGH FRIDAY/...
SHORT TERM /through 12z Tues/...
As of 1:30 AM Monday...VFR SKC conditions continue to prevail.
Light winds will veer from the southwest to northeast this
morning and accompany fair weather cu ahead of a cold front
approaching from the north. PoPs will increase in the afternoon
as the cold front sags south and sea/river/sound breezes move
provide ample lift for showers and thunderstorms. Coverage is
expected to be scattered, but high PWATs may support heavy rain
at times. The most likely window of sub-VFR CIGs and VIS for
all terminals will be between 19-00z. PoPs will diminish after
sunset but SCT to BKN 3-5 kft clouds will linger through the
evening. CIGs will continue to drop overnight with western
terminals most likely to see MVFR to IFR CIGs early tomorrow
morning.

LONG TERM /Tue through Fri/...
As of 2 AM Mon...High pressure generally in control Tue with
only sct diurnal showers possible. Light winds on Tue expected,
and will inc a bit on Wed with gusts in the 15-20kt range. An
uptick in winds Wed night into Thu as Hurricane Erin makes its
closest approach to ENC, with gusts of 20-30kt possible, though
any tropical storm winds will remain relegated to the coastal
counties. More organized outer rain bands should remain east of
the TAF sites Wed night into Thur, and rain chances are
generally 30% or lower.

&&

.MARINE...
SHORT TERM /through Monday/...
As of 3 AM Monday...Winds will be light and variable for most of
today but will become northeasterly at 10-15 kt by this evening.
Conditions will start to deteriorate tonight as Hurricane Erin`s
powerful long period swell enters our coastal waters. Seas will be 2-
4 ft at 10-12 seconds today and increase to 5-8 ft at 14-17 seconds
by early Tuesday morning. A SCA is in effect for the coastal
waters south of Oregon Inlet starting at 00z with the northern
waters following suit at 06z. Marine conditions will become
increasingly life threatening thereafter.

LONG TERM /Tue through Fri/...
As of 2 AM Mon...Long period swell ramps up through the day and
overnight on Tue, with dangerous 6-9 ft seas by late day Tue inc
to 8-12 ft late Tue night. Extremely treacherous conditions Wed,
peaking Wed night into early Thu as Hurricane Erin makes her
closest approach to ENC with a very large wind field. This will
bring extremely life threatening marine conditions reaching
their worst during this time, with seas peaking 15-20+ ft, and
N to Nerly winds peaking in the 25-35 kt range, gusting to 35-45
kt. Wave heights and wind gusts are subject to change and will
be dependent on Erin`s eventual track and intensity, which have
yet to be determined.

&&

.TIDES/COASTAL FLOODING...
As of 2 AM Mon...

Key Messages:

- Coastal Flood Watches and High Surf Advisories remain in
  effect through as late as Friday evening. Worst conditions are
  expected late Wednesday through Thursday as Hurricane Erin
  makes it`s closest approach to ENC.

- Life threatening rip currents are expected all week.

Strong long period swell associated with distant but large and
powerful Hurricane Erin will occur simultaneously with higher
astronomical tides, exacerbating coastal flooding threats.
Significant coastal flooding/ocean overwash/erosion is likely,
especially around the high tide cycles. Impacts are expected to
start as early as Tuesday afternoon`s high tide cycle, peak
Wednesday into Thursday, and only slowly improve late week.
While all area beaches are expected to see impacts, E to SE
facing beaches are most likely to see the highest waves (10+ ft)
and roughest surf zone conditions. Hatteras and Ocracoke
Islands are especially vulnerable to even higher waves (15-20
ft) and may experience major coastal impacts, including portions
of Highway 12 and secondary roads which may become impassable
and/or inaccessible in places for several days.

Based on the current forecast track, moderate to major flooding
will mainly be focused along the oceanside. However, due to the
expected large wind field with Erin, minor soundside flooding
on lower Pamlico Sound and it`s adjacent tributaries are also
possible due to winds reaching or exceeding tropical storm
strength along the coast.

&&

.MHX WATCHES/WARNINGS/ADVISORIES...
NC...Coastal Flood Watch from Tuesday afternoon through Thursday
     evening for NCZ195-199.
     High Surf Advisory from noon Tuesday to 8 PM EDT Thursday for
     NCZ195-199.
     Beach Hazards Statement through this evening for NCZ196-
     203>205.
     Coastal Flood Watch from Tuesday afternoon through Friday
     evening for NCZ196-203>205.
     High Surf Advisory from noon Tuesday to midnight EDT Friday
     night for NCZ196-203>205.
MARINE...Small Craft Advisory from 2 AM Tuesday to midnight EDT Friday
     night for AMZ150.
     Small Craft Advisory from 8 PM this evening to midnight EDT
     Friday night for AMZ152-154-156-158.

&&

$$

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