435
FXUS62 KILM 180650
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
150 AM EST Thu Dec 18 2025

.SYNOPSIS...
Rain chances will increase later today and tonight ahead of a
cold front that will move off the coast Friday. Canadian high
pressure will build across the area Saturday. A dry cold front
arriving Sunday will bring chilly weather for Monday, but a
warming trend is expected to begin later next week with above
normal temperatures by Tuesday and Wednesday.

&&

.NEAR TERM /THROUGH THURSDAY NIGHT/...
Southeasterly flow increases today as high pressure slides offshore.
A coastal trough will push onshore this morning and could produce a
few isolated showers. The chance of precip will be low, highest in
northeastern SC and the Grand Strand. Behind the initial surface
trough, warm, moist air advection will push temperatures into the
upper 60s to near 70. Mostly cloudy skies this morning will become
overcast during the afternoon.

A pre-frontal shortwave will bring showers across the region later
today and tonight. Light rain will spread SW to NE across the region
by early or mid afternoon. The Cape Fear region should stay dry
until after sunset, but points southward will see intermittent
showers after 2 PM. Shower coverage becomes more uniform after
sunset as the pre-frontal shortwave slides overhead.

Maximum synoptic lift and saturated atmospheric profiles will
produce moderate to heavy rain this evening. An approaching upper
level trough to our west will gradually bring lower heights during
this time as well. This should produce some elevated instability
near the coast leading to heavier rain rates. HREF guidance
continues to suggest that the bulk of this instability will remain
offshore. Regardless, I have maintained the mention of a few
localized thunderstorms from Georgetown to Surf City. A briefly
enhanced gust would be possible near the coastline, if anything
materializes, but severe weather is not expected.

The actual cold front will lag the end of the precip by several
hours late tonight and Friday morning. This should maintain low
clouds and humid conditions until the frontal passage around noon on
Friday. The surface gradient should prevent the development of fog
across the region, but Friday will start with mostly cloudy or
overcast skies and mild temperatures in the lower 60s.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
A shortwave extending across the central Appalachians Friday
morning will attain a slight negative tilt as it lifts across
the northeastern U.S. Friday night. Right entrance region
effects from the jet streak should remain to our north. However
there is a narrow window of time during the morning where
residual low level moisture and steepening low level lapse rates
could coexist, allowing some fast-moving convective showers to
develop especially across southeastern North Carolina.

These steepening lapse rates have a high probability of
producing widespread gusty winds on Friday. NAM and GFS forecast
soundings show winds only 1000 feet AGL could exceed 30 knots
(35 mph) during the morning, diminishing to 25 mph during the
afternoon as winds veer westerly behind the actual surface cold
front. This is a good approximation for expected wind gusts at
the surface.

Surface high pressure will build eastward Friday night, reaching
North Carolina on Saturday. The high will slip off the coast
Saturday night with light return flow developing.

NBM temperatures look acceptable during the period. Radiational
cooling both nights could knock typical cold spots on
peat/pocosin soils 10 degrees F below nearby cities.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Another shortwave moving through the Great Lakes and the
northeastern U.S. on Sunday will support sub-1000 mb surface low
pressure moving eastward over southern Quebec. This low will
drag a dry cold front through the eastern Carolinas during the
day. Behind it, a chilly airmass will build across the area for
Monday with daytime highs only anticipated to reach the lower
50s. Canadian high pressure following behind the front should
reach the area Monday night.

As the shortwave clears off to the east, the upper air pattern
should change across North America as ridging develops along
the Gulf Coast and northward through the Mississippi Valley.
An average of the GFS, ECMWF, and Canadian suggests our
1000-500 mb thicknesses will rise almost 100 meters between
Monday and Wednesday as the airmass warms. Daytime highs could
poke back toward 60 on Tuesday and into the mid 60s by Wednesday
(Christmas Eve) as dry weather continues.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
Fog and associated restrictions have been localized early this
morning and will gradually end through sunrise as boundary layer
winds increase. Models had previously mentioned the potential for
low clouds, but boundary layer saturation is marginal.

Isolated showers are possible this morning as a coastal trough moves
inland. If impacted, terminals are likely to only fall to MVFR
briefly. VFR should develop after mid morning in warm advective
flow. Gusts increase to around 15 knots in the increasing SE
gradient. Showers spread SW to NE across the region after 18Z-20Z.
Showers should be light at first, with increasing intensities toward
Thursday evening.

A few thunderstorms are possible near the coast after 00Z, but the
best instability should remain just offshore. Regardless, rainfall
intensities should increase. Most areas will see IFR decreasing to
LIFR/VLIFR as low level inversions are reinforced. This inversion
should also produce fairly strong wind shear.

Extended Forecast... High confidence in IFR on Friday morning with
gradual improvement to VFR throughout the day. VFR conditions
continue into early next week.

&&

.MARINE...
Through Tonight...Onshore flow will increase today ahead of an
approaching cold front and leading mid level shortwave. With a
gradually increasing gradient, warm advection during the daylight
hours should limit mixing efficiency with gusts generally around 20
knots. Seas build to 3-4 feet by mid afternoon with a rapid increase
in wind energy thereafter.

The strengthening gradient will become maximized during the late
afternoon and evening. Surface winds should exceed SCA thresholds by
00Z for all nearshore waters with wind waves quickly responding to 4-
6 feet during that time. Heavy rain and isolated thunderstorms will
limit visibility and lead to locally higher winds and seas. Winds
turn S and SSW overnight as the cold front approaches the coast.
Ongoing SCA gusts will continue through the end of the period. A SCA
remains in effect starting at 23Z Thursday.

Friday through Tuesday...A cold front extending southward from
Canadian low pressure will push off the Carolina coastline
Friday. SW winds near 25 kt in the morning will veer westerly
15-20 kt in the afternoon. Small Craft Advisory conditions may
continue through early evening due to lingering 6 foot seas.

High pressure will build across the area late Friday night. The
center of the high will reach coastal NC Saturday afternoon,
pushing offshore Sunday night. This will be quickly followed on
Sunday by the arrival of a dry cold front. Models show a rather
impressive surge of northerly winds developing Sunday night,
veering northeasterly and lasting through Monday and perhaps
into Monday night. This surge has a good chance of forcing
another Small Craft Advisory due to 25 knot winds and 6 foot
seas. Lighter winds appear likely for Tuesday as high pressure
builds across the area.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
NC...None.
SC...None.
MARINE...Small Craft Advisory from 6 PM Thursday to 9 PM EST Friday for
     AMZ250-252-254-256.

&&

$$

SYNOPSIS...TRA
NEAR TERM...21
SHORT TERM...TRA
LONG TERM...TRA
AVIATION...21
MARINE...TRA/21