765
FXUS62 KILM 040736
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
336 AM EDT Wed Jun 4 2025

.SYNOPSIS...
High pressure`s influence over the region will weaken today as weak
low pressure moves north, increasing rain chances. Shower and
thunderstorm chances remain elevated into Thursday night,
especially near the coast. Warmer and more humid weather will
accompany scattered showers and thunderstorms over the weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
Latest surface analysis shows high pressure continuing to push
offshore of the OBX, while an inverted coastal trough is starting to
mature just offshore of the Florida Atlantic coast. This trough and
its eventual surface low will be the focus of the forecast through
tonight.

This trough will drag itself along the Atlantic coastal border,
pushing the high pressure completely out of the picture by midday.
Moisture is already increasing through the atmospheric column, with
precipitable water values already near an inch in parts of
Williamsburg and Georgetown Counties, per the SPC Mesoanalysis page.
Cirrus clouds have gradually increased in coverage through the
overnight hours, but it`ll take awhile for the rain to get here.
Scattered showers and a few embedded thunderstorms will start
filling in over northeast SC by midday. By the time the coastal
trough axis approaches Savannah late this afternoon into this
evening, rain chances really start to become widespread. The most
impressive piece here is that precipitable water values soar up to
and above 2 inches by this evening, which is near the climatological
maximums for this time of year across the CHS, MHX, and HAT sounding
archives.

Warm cloud processes and convective rainfall spell out the potential
for periods of moderate to heavy rainfall. Along and west of I-95,
further away from the moisture axis, rainfall amounts through
tonight look to be around three-quarters an inch or less, but if the
system overperforms, we could see 1.0-1.5" in that area. Cape Fear
region could see an inch or more, while the Grand Strand region
looks to be the epicenter of the event (generally 1.5-2.5 inches).
Most of the higher amounts stay offshore, but there`s potential (10-
20%) that the Grand Strand area could record 3-4 inches. Evening and
overnight hours will record the bulk of the rain.

Highs generally in the low-to-mid 80s, although thick clouds and
rain may limit parts of the Grand Strand to the upper 70s. Lows
tonight in the upper 60s to near 70.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
The short term will be made up of two distinctly different days.
Cool and damp conditions on Thu will shift to warmer and drier on
Fri as low pressure exits to the northeast. Impressive plume of
tropical moisture in the region on Thu with precipitable water
across the area approaching 2.25" or 150-160% of normal. Although
temperatures on Thu will be 5 degrees or more below normal, limiting
surface based instability, there will be plenty of dynamics to
support widespread, heavy rain. Weak low pressure trying to become
more organized along or just inland from the coast, divergent flow
aloft ahead of a shortwave trough emerging from the Deep South and
healthy dose of PVA. The potential for high rainfall amounts
continues due to the aforementioned factors and a deep warm cloud
layer increasing rainfall efficiency. The largest limiting factor
for excessive rainfall will be how quickly the event evolves. If the
evolution is slower than currently being depicted by the guidance,
the potential for excessive rainfall and localized flooding
increases.

It`s looking like the bulk of the action on Thu will be through
early to mid afternoon before drier air starts spreading in from the
west and subsidence in the wake of the shortwave trough/low starts
to develop. There is more uncertainly with respect to the timing
than is typical for a day 2 forecast. The trend has been for faster
motion of the low, if this continues it`s possible the later half of
Thu could be drier than forecast and with less rainfall on Thu.

Following the exit of the shortwave and the developing low, drier
air spreads in from the west. There is enough dry air to knock PWATs
back to near to slightly below normal, although there will still be
a fair amount of moisture around. The bigger difference will be the
increase in stability. Forecast soundings depict an inversion
roughly in the 800-850 mb layer. Forecast temps do not get warm
enough to break this cap, which in theory should lead to limited
coverage of diurnal convection. Cannot rule out something isolated
developing along the pinned sea breeze, but marginal mid-level lapse
rates and a lack of mid-level support suggest anything that develops
will be short-lived and weaker.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
Active weather abounds in the long term with flat flow aloft
gradually becoming amplified as a broad 5h trough sets up over the
East Coast. Not much in the way of surface features on Sat with more
typical diurnal showers and thunderstorms developing, generally
inland from the coast. Changes come early Sat night as a pre-frontal
trough moves in from the northwest, possibly with an MCS. A front
follows the MCS ands ends up stalled in the area Sun. The stalled
front, precipitable water around 2 inches, surface heating and PVA
arriving in the afternoon all point to Sun being a day with
widespread showers and thunderstorms. The front lifts north on Mon,
but all of the other environmental parameters remains unchanged and
the developing 5h trough with the axis to the west ensures more
shortwave energy and divergent flow aloft. Not much changes for Tue,
except a weak front moves into the western Carolinas in the
afternoon, enhanced the low level jet. Highs will be near to above
normal with lows running above normal.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
VFR to open the 06Z TAF period. Some MVFR ceilings are lingering
near KGGE, and may push over towards KCRE/KMYR over the next
couple of hours. E to SE winds will pick up later this morning
to near 10 kts, gusting near 20 kts in the afternoon as a system
moves in from the SSW. This will cause conditions to become
solidly MVFR and possibly IFR starting with coastal SC
terminals, then KFLO, then KILM/KLBT. Showers will follow the
drop in ceilings, becoming more widespread after 21Z. Embedded
TSRA was represented at each terminal, mostly using PROB30
groups.

Extended Outlook...High confidence in established MVFR/IFR
Wednesday night. Next weather system brings more rain chances
and flight restrictions Thursday through the weekend.

&&

.MARINE...
Through Tonight...
ESE winds at 10-15 kts will gradually veer to the SSE as a low
pressure system approaches the area. Gusts up to 20-22 kts look
more likely over the northeast SC coastal waters. Seas currently
at 2-4 ft will gradually build up to 3-4 ft at the coast, 4-5
ft out 20 nm from shore, particularly along the northeast SC
coastal waters.

Thursday through Sunday...
Southeast flow early Thu will veer to south then southeast
during the day as low pressure passes just west of the waters.
The low remains fairly weak as it passes, keeping wind speeds
around 15 kt. The low lifts north of the area Thu night and flow
becomes offshore. May see a slight increase in wind speeds
later Thu night and Fri as the low begins some slow
strengthening after emerging off the NC coast. Winds then back
to southwest for the weekend with first a trough that moves to
the coast later Sat and then a weak front on Sun. May see speeds
briefly approach 20 kt later Sat, given the trough and the
strong inland heating, but not expecting speeds above 20 kt.
Highest seas on Thu with 3-5 ft due to the extended period of
southeast flow helping to build up a southerly swell. Once the
offshore flow develops seas will start decreasing with a wind
wave gradually becoming more pronounced. Winds backing to
southwest and then increasing slightly could bring back 3-5 ft
seas, a mix of a southerly swell and a west-southwest wind wave,
although the current forecast does not call for this.

&&

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

&&

$$

SYNOPSIS...ILM
NEAR TERM...IGB
SHORT TERM...III
LONG TERM...III
AVIATION...IGB
MARINE...III/IGB