932
FXUS62 KILM 241045
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
645 AM EDT Sun Aug 24 2025

.SYNOPSIS...
Weak low pressure along the coast will move northeastward and
away from the Carolinas tonight, allowing drier weather to
develop. A Canadian cold front will move off the coast Monday
night with below normal temperature and humidity expected
through the remainder of the week.

&&

.UPDATE...
Updated some of the hourly rain chances to correspond with
ongoing rainfall in coastal Georgetown and Horry Counties.
Otherwise, no major changes coming down the track as we approach
7 AM EDT.

Updated 12Z TAF discussion found below.

&&

.NEAR TERM /THROUGH TONIGHT/...
Latest surface analysis shows a weak low about 80 nautical miles
offshore of Lowcountry and the Grand Strand. This low has continued
to spawn scattered showers along the coast and offshore, especially
in locations closer to the low itself. Not much lightning seen here,
and even so, most of it is well offshore over the Gulf Stream.

This low will continue to track northeastward through this period,
eventually ending up near the Outer Banks by this evening, and then
further offshore by late tonight. Interestingly enough, HREF
ensembles are finally catching onto the offshore track of this low,
which did not look apparent this time last night. This appears to be
a rare win for the global ensembles and deterministics, considering
the smaller, minute features here.

Turns out, this offshore track plays a rather critical role today
when it comes to rainfall amounts. While I certainly feel good about
scattered showers and perhaps a few rumbles of thunder periodically
scraping the coastline throughout the day, I don`t think we`re going
to see much in the way of accumulation. Several hours ago, some data
was a bit more keen on some possible amounts of 1+ inches north of
Cape Fear, but now, chances are rather slim that we`ll see even half
an inch through tonight. This is rather ironic, given that the
atmosphere is in a favorable environment otherwise (precipitable
water values of 2.00-2.10" along the coast, good moisture transport
from 925-850mb, quasi-stationary lobes of vorticity up to 700mb
along the coast, and some deep moisture convergence). About the only
thing missing is that the isentropic upglide doesn`t look all that
impressive. The offshore track of the low seems to be saving the day
here, at least for now. If this low starts tracking a bit closer to
the coast, expect rainfall amounts to increase accordingly, and some
may score an inch of rain or more. All in all, we`re riding a pretty
fine line here.

At any rate, once the center of the low starts pulling northeast of
Cape Fear by this afternoon, it`ll take some of the moisture out of
the picture, eliminating the rain chances for the northeast SC coast
by this afternoon, and then for the southeast NC coast by this
evening.

Highs in the mid 80s, lows tonight in the upper 60s to lower
70s.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
This weekend`s coastal low should be quickly moving northeastward
well off the Mid Atlantic coast Monday morning. In its wake a cold
front extending south from low pressure over Quebec should move into
the eastern Carolinas during the day Monday. Although Monday`s
airmass will be drier than Sunday`s, enough moisture and diurnal
instability should develop to fuel isolated showers and
thunderstorms, especially near the coast. Triggers will include the
seabreeze plus frontal low-level convergence. Areas west of of
Elizabethtown, Whiteville, and Marion will likely get into the dry
air too quickly on Monday for any rain chance to develop. Highs
should reach the upper 80s to near 90.

The front will work its way offshore Monday night allowing drier air
from Canada to overspread the area Tuesday. Dewpoints are
anticipated to fall into the 50s inland with lower 60s near the
coast. All this low level dry air won`t immediately equal clear
skies as there may be substantial cirrus clouds aloft as a cold
upper trough digs across the Ohio Valley and strengthening SW flow
develops over the Carolinas at and above 500 mb. After mid 80s
during the day Tuesday, lows Tuesday night should fall to 63-66
inland with upper 60s for the coastal cities. (Wilmington,
Southport, Myrtle Beach, and Georgetown)

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
This summer has been a hot one and may end up in the top ten
hottest summers on record in Wilmington, Myrtle Beach, and
Lumberton. However the final few days of climatological summer
look to be particularly mild with temperatures likely cool
enough to open windows at night.

A longwave trough should remain in place Wednesday through the
coming weekend. One impressive shortwave will move off the Mid
Atlantic coast Wednesday followed by another a little farther north
on Friday. Low level northeast winds will maintain below normal
temperatures with daytime highs in the lower 80s and nighttime lows
around 60 to the lower 60s inland with mid to upper 60s on the coast.

Shallow cumulus clouds should develop at the top of the daytime
mixed layer each day. 18z Saturday GFS forecast soundings suggest
there may just enough depth to the instability to get a few coastal
showers to develop Friday and Saturday, but there also should be a
lot of dry air aloft above the low level northeast flow likely
limiting coverage and accumulation.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
Mostly VFR to open the 12Z TAF period, for now. MVFR ceilings
are dancing all around KILM, KCRE, KMYR, and even KLBT, but
haven`t stuck around any of the terminals for any significant
period of time. Wondering if this will continue to be the theme
throughout the morning as this coastal low remains offshore,
even with the rain. KILM, KCRE, and KMYR stand the greatest
chances at going down to MVFR for a prolonged period of time. KFLO
and KLBT should be saved from this mess, with only VFR ceilings
in play.

The bulk of the rain should mostly hang offshore, though a few
showers are likely to scrape the coast, which is what is
happening now in Georgetown and Horry Counties. Timing this has
been perhaps the most difficult. Gained enough confidence to
throw in some TEMPO groups for much of this morning. Should see
mostly SHRA or RA here, with thunder remaining well offshore.
Offshore low pressure should pull off to the northeast this
afternoon, eliminating the rain chances and MVFR concerns by
18-21Z. Winds generally out of the northeast, becoming light and
variable by this evening.

Extended Outlook...Low confidence in some isolated flight
restrictions due to showers and storms along the coast Monday
afternoon. Otherwise, high confidence in VFR through Thursday.

&&

.MARINE...
Through Tonight...E to ENE winds at 10-15 kts back to the NNE by the
mid-morning hours, with speeds decreasing to 5-10 kts by the
afternoon. Winds will then start to back to the WNW by this evening
and overnight hours. Seas mostly 2-4 ft at first, but gradually
decrease to 2-3 ft by this evening. Some of the pesky long period
swells from formerly-known-as-Erin remain out of the ENE, but
otherwise, easterly and southeasterly swells at 5-6 seconds will be
recorded.

Monday through Thursday Night...This weekend`s low pressure
system should be located off the Mid Atlantic coast and moving
quickly away from the Carolinas Monday morning. A substantial
cold front (by late August standards) will move southeastward
across the inland Carolinas during the day Monday, finally
moving off the coast late Monday night. Southwest winds should
shift behind the front to the north and northeast for the
remainder of the week. Models are hinting that low pressure may
try to develop along the stalled front a few hundreds miles east
of the South Carolina coastline Thursday. This could lead to an
enhancement of the northeast flow down the coast late in the
week.

Our new forecast will feature southwest winds near 10 knots ahead of
the front Monday and Monday night, then shifting north to northeast
Tuesday around 10 knots. Wind speeds should increase to 10-15 knots
Wednesday through Thursday, perhaps even a little higher than 15
knots if the offshore low can take shape.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
NC...Coastal Flood Advisory until 10 AM EDT this morning for NCZ106-
     108-110.
     Coastal Flood Advisory until 2 PM EDT this afternoon for
     NCZ107.
SC...Coastal Flood Advisory until 11 AM EDT this morning for SCZ054-
     056.
MARINE...None.

&&

$$

SYNOPSIS...TRA
UPDATE...IGB
NEAR TERM...IGB
SHORT TERM...TRA
LONG TERM...TRA
AVIATION...IGB
MARINE...TRA/IGB