Mc Coll, South Carolina Weather Forecast Discussion

785
FXUS62 KILM 190537
AFDILM
Area Forecast Discussion
National Weather Service Wilmington NC
137 AM EDT Fri Sep 19 2025
.SYNOPSIS...
Warm and dry weather will continue into the weekend as high
pressure builds in. Near to slightly above normal temperatures from
Sunday into next week with low rain chances each day associated
with a coastal trough.
&&
.NEAR TERM /THROUGH TONIGHT/...
A weak ridge of high pressure extending from the surface up
through 700 mb will remain across the Carolinas today. This
should provide a second day of light winds and warm daytime
temperatures. Before the sun comes up this morning, however,
shallow moisture that came in with yesterday`s seabreeze should
create areas of locally dense fog that may last through 9-10 am
before burning off. We`ll watch visibility trends closely to see
if we need a short- fused Dense Fog Advisory. Fog won`t affect
this afternoon`s highs which still should approach 90 degrees
along and west of I-95, with low-mid 80s near the coast with
another well-defined seabreeze circulation.
Isolated showers yesterday dropped up to half an inch of rain just
west of Georgetown, SC. While forecast soundings show similar lapse
rates and computed CAPE values this afternoon, there also appears to
be a little more dry air aloft today versus yesterday. While
isolated showers are still possible along the seabreeze front, areal
coverage should remain less than 10 percent.
Tonight should have broadly similar conditions to this morning
(light winds plus shallow low-level moisture from the seabreeze)
that may yield areas of fog late. Forecast lows range from 62-66,
except a bit warmer on the beaches.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
On Saturday, as a powerful mid-upper trough swings away into far
southeastern Canada and an associated strong surface high pressure
area slides into New England, a cold front will settle southward,
reaching the area by late in the day. Expect the boundary to stall
over or near the area with a slightly cooler and drier air mass
taking hold as a surface pressure wedge becomes well-established
over Saturday night into Sunday. The tightening pressure gradient
will result in breezy east to northeast winds from Saturday onward,
especially as an inverted trough takes shape offshore. With no
notable lifting mechanisms aloft, these breezy conditions should be
the predominant impact on sensible weather, with only a slight
chance for offshore showers to reach the coast as dry air and
subsidence aloft will otherwise continue to keep rain largely at
bay. Low-level moisture coming off the ocean should also result in
greater cloud cover near the coast on Sunday, with these clouds
thinning as one goes inland.
Temperatures over the weekend should end up within a few degrees of
seasonable levels, with mostly sunny skies and mid-upper 80s on
Saturday, and greater cloud cover and onshore flow leading to low-
mid 80s on Sunday while overnight lows fall mainly into the middle
60s both nights, except upper 60s to around 70F at the beaches.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
The cool air damming wedge should continue into Tuesday, with the
supporting high pressure center becoming increasingly elongated and
weakening with time. The stalled front should also be near the coast
or drifting offshore, keeping east to northeast winds going and low
clouds in place. Going into midweek, an approaching mid-level trough
should lead to unsettled weather at some point, but how the guidance
tools handle the breakdown of the high and evolution of the trough
still differs considerably, leading to a very low confidence
forecast after Tuesday. How temperatures respond will of course
depend on cloud cover and any precip, so be aware that changes are
likely until the future outcome of this trough becomes clearer.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
Light winds plus shallow moisture brought onshore behind yesterday
afternoon`s seabreeze should help develop areas of fog across the
eastern Carolinas this morning. Confidence is high that IFR
visibility will develop at all local airports sometime between 09-
12z, with moderate confidence that visibility may crash all the way
down to 1/4 mile around sunrise. The fog layer should remain very
thin and will burn off quickly between 13-14z with VFR conditions
anticipated throughout the remainder of the day.
Extended Outlook...There is moderate potential for ground fog with
MVFR to IFR visibility or low stratus each morning through the
weekend, mainly between 06-12z. Some potential for isolated showers
may return early next week, but confidence is low.
&&
.MARINE...
Through Tonight...A weak ridge of high pressure will extend east-to-
west across the Carolinas today providing light synoptic winds and
continued dry weather. With such a light pressure gradient, the
seabreeze/landbreeze circulation will dominate the winds: light
offshore winds this morning will increase from the east and
southeast to around 10 knots this afternoon across the nearshore
waters, then should turn back to light northerly late tonight. Seas
should average only 1-2 feet.
Saturday through Tuesday... Rather strong high pressure north of the
area will send a cold front southward, with it likely stalling
inland of the coast on Saturday. Nevertheless, an inverted trough is
expected to develop over the offshore waters, leading to a
tightening gradient and increasing east to northeast winds from
Saturday onward. A weak low pressure area may also form along this
trough and stay well offshore. Peak winds look to occur on Sunday,
although trends continue to point towards conditions falling just
shy of Small Craft Advisory levels. The wedge pattern breaks down by
Tuesday, with the gradient loosening up and this leading to
decreasing winds and seas. NE to ENE swells will be the predominant
wave group with a period around 6-7 sec.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
NC...None.
SC...None.
MARINE...None.
&&
$$
SYNOPSIS...ILM
NEAR TERM...TRA
SHORT TERM...ABW
LONG TERM...ABW
AVIATION...TRA
MARINE...TRA/ABW

NWS ILM Office Area Forecast Discussion