758 
FXUS62 KILM 061326
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
926 AM EDT Mon Sep 6 2021

.SYNOPSIS...
Seasonal temperatures and humidity returns Monday. Showers and
storms possible Tuesday through Thursday due to a couple of cold
fronts passing through the area. The forecast will then dry out
by next weekend. Hurricane Larry continues to stay at sea, but
swells will enter local waters this week, creating dangerous rip
currents at area beaches.

&&

.UPDATE...
Last of the dense fog and low stratus across inland NE SC is 
dissipating this morning. Weak cold front east of the 
Appalachians continues its slow progress eastward, with low pops
(20-30%) still in the forecast beginning this afternoon into 
overnight hours. Widely scattered showers expected, with limited
thunderstorm potential. Best chance for isolated thunderstorm 
will be inland NE SC late this afternoon and evening. Front 
stalls across the area overnight and low pops remain in the 
forecast, with focus shifting towards the coast after midnight.

&&

.NEAR TERM /THROUGH TUESDAY/...
A weak surface cold front now 
crossing through the southern Appalachians will stall across 
the eastern Carolinas this evening. Upper level support is 
unimpressive as a shortwave moving across the Great Lakes today 
lifts across northern New England tonight, leaving only a 
dangling shear axis aloft over the Southeast. Precipitable water
values will increase to near 2.0 inches and sufficient 
instability will develop that I'll need to continue the small 
(20-30 percent) chance of showers/t- storms in the forecast. The
leading edge of the higher PW plume suggests precip chances 
will develop by mid afternoon across the Pee Dee region, then 
this evening along the coast.

The stalled front should continue to weaken on Tuesday, then 
will dissipate entirely during the afternoon as the seabreeze 
washes out what's left of the boundary. The airmass should be 
even a little more humid and unstable than today, driven by mid 
level cooling of 1- 2 degrees C. Rain chances of 20-40 percent 
are in the forecast, highest across South Carolina just inland 
from the coast.

Highs both today and Tuesday should reach the upper 80s with a 
couple 90 degree readings possible in spots. Local temperature 
verification shows the GFS MOS has performed the best of all 
guidance over the past few days.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
Old frontal boundary roughly bisects the area in a southwest to
northeast fashion, lifting northward slightly by Wednesday. A 
stronger cold front starts dropping southward from the Ohio 
River Valley Wednesday. Associated upper trough digs into 
Appalachia Wednesday and Wednesday night, causing a surge in SSW
flow aloft. The old frontal boundary will combine with 
increasing warm air and moisture advection to create chances for
convection Wednesday afternoon and evening.

Swells from Hurricane Larry start arriving before sunrise 
Wednesday, which will attribute to increasingly dangerous rip 
currents along area beaches. Please see weather.gov/beach/ilm 
for the latest surf forecast.

Highs Wednesday linger near 90 inland with mid-to-upper 80s at 
the coast, which is near or just above normal for early 
September. Lows consistently hang in the lower 70s.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
At the start of the period, stronger cold front will start to 
enter the forecast area. Best upper level support comes by 
Thursday afternoon, as the trough digs and swings through, 
promoting positive vorticity advection. Shear parameters don't 
look super impressive right now, as the jet stream doesn't quite
reach south enough. However, if the jet digs deeper, it could 
create more potential for a few strong storms. For now, kicked 
up the shower and storm chances just a tad by Thursday 
afternoon. The front will push towards the coast and offshore by
Thursday night.

High pressure settles in behind the front, creating a dry 
weekend with plenty of sunshine and less humid air. High 
temperatures throughout the period linger near normal, with low 
temperatures running 2-5 degrees below normal after the frontal 
passage.

Most important highlight in this period is the increased swells
coming into the local waters from Hurricane Larry. The good 
news is that Larry stays out at sea, but swells will create 
dangerous rip currents by midweek. Extreme caution is needed 
here, especially since rip currents are the #1 weather-related 
killer around these parts. A Small Craft Advisory will likely be
needed Thursday through Saturday. See the marine discussion 
below for more details.

&&

.AVIATION /14Z MONDAY THROUGH FRIDAY/...
IFR fog will mix out quickly this morning. A frontal boundary
will stay just west of the CWA, with isolated convection
possible west of the I95 corridor. Moisture on the increase
tonight with a mid cloud ceiling.

Extended Outlook...Mainly VFR. Isolated to scattered showers 
and thunderstorms Tue though Thu could bring brief flight 
category restrictions.

&&

.MARINE...
Through Tuesday...A weak cold front crossing the southern 
Appalachians this morning will stall across the eastern 
Carolinas tonight, bringing the potential for isolated showers 
or even a thunderstorm to the coastal waters. This front will 
weaken and dissipate Tuesday, but an increasingly humid airmass 
could still allow an isolated shower or t-storm to linger, 
especially near the beaches and inland. Otherwise light winds 
are expected to continue with afternoon seabreezes both days 
turning wind directions onshore.

Seas are currently around 2 feet a mix of southeast 10 second 
swell and southwest wind chop. A 17 second southeast swell from 
distant Hurricane Larry will begin to show up tonight but won't 
build appreciably in height until later in the week.

Tuesday Night through Friday...SSW flow continues through 
Thursday afternoon, as a cold front approaches the area. Winds 
stay mostly near 10kts throughout this time, though they could 
increase to 15kts Wednesday night. After frontal passage, winds 
veer to the north late Thursday night, becoming northeasterly 
throughout Friday, with speeds holding steady at 10kts. 
Hurricane Larry stays out at sea, but swells start entering 
local waters at the beginning of this extended period. Seas 
2-4ft Wednesday could increase to 2-4ft seas at the coast, and 
5-6ft seas out 20nm from the beaches by Thursday. A Small Craft 
Advisory is likely needed as early as Thursday morning. The peak
of this activity comes in by Friday afternoon, with 7ft waves 
possible. Swells look to have very long periods, generally 15+ 
seconds. Dangerous rip currents will also be a concern along 
area beaches. Extreme caution will be needed on the water.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...None.

&&

$$
SYNOPSIS...ILM
UPDATE...VAO
NEAR TERM...TRA
SHORT TERM...IGB
LONG TERM...IGB
AVIATION...43
MARINE...TRA/IGB