-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KILM 201734
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
120 PM EDT Sat Apr 20 2024

.SYNOPSIS...
A front will move south across the Carolinas today, stalling to
our south tonight. Low pressure developing along this front
should lead to widespread rain Sunday. High pressure will
gradually build in from the northwest bringing dry weather back
to the Carolinas by Monday night and Tuesday and lasting
through much of next week.

&&

.UPDATE...
-- Changed Discussion --
Aviation update below but have changed the going forecast as well.
12Z guidance as well as some successive CAM runs are coming into
some agreement that a batch of thunderstorms with some semblance of
organization/cold pool dominance will affect the area, mainly NC.
Have raised POPs and will update the HWO, though not quite put
enhanced storm wording in grids. SPC meso page already showing 2500
J/Kg of SBCAPE in the areas in question.
-- End Changed Discussion --

&&

.NEAR TERM /THROUGH TONIGHT/...
A cold front will move through the area during the AM hours,
stalling near the coast come the afternoon. Low pressure will
develop along the front near the SC coast, Gulf moisture being
pulled NE into our area. Scattered activity expected during the
afternoon due to these increased PWATs paired with instability from
daytime heating. Thunder chances will be higher near the coast due
to the frontal boundary. Heights continue to fall overnight with
precip chances increasing over the area as the low deepens offshore.
Temperatures will be tricky due to the front in the area, but
lowered inland temps due to the frontal passage. Regardless, we`ll
still warm into the 80s, lower 80s inland and upper 80s near the
coast. Lows in the mid to upper 50s.

&&

.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
A cool surface airmass will exist across the Carolinas north of
a front stalled near Savannah, GA Sunday. The approach of a
southern stream shortwave should lead to increasing isentropic
lift over the shallow cool airmass. Rain is expected to
overspread the area during the day and forecast PoPs are 90-100
percent. Forecast soundings show mid level lapse rates (above
the cool surface layer) are steep enough there may be embedded
convective elements within the broad stratiform rain, but I`m
not including thunder at this time. I`ve adjusted temperatures
down a couple degrees below the default model blends and will
likely end up favoring the cooler GFS MOS for Sunday`s highs.

This wave of isentropic lift should taper off Sunday night as
this first shortwave passes overhead. Clouds may begin to
break overnight, however total clearing will have to wait at
least another 24 hours as a northerly stream trough will
approach the area Monday.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
The second upper system should help develop an area of low
pressure along the baroclinic zone off the GA coast,
potentially spreading a few showers back along the Carolina
coast Monday. Clouds will also hang on, especially east of
I-95. Once this upper trough moves overhead Monday night skies
should clear rapidly as the Carolinas come under the influence
of surface high pressure moving southeastward from the Upper
Midwest. Diurnal ranges will become larger as generally dry
weather and clear skies are expected for the second half of the
week.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
-- Changed Discussion --
Wind will remain light and become increasingly variable as a front
drops into the area this afternoon. This boundary will initiate
thunderstorms that may have strong winds as they push south and
east. LBT and ILM have the best chance to see stronger storms.
Ceilings also lowering with the front, liking descending to IFR area-
wide. Stratiform rain then spreads west to east across the area
towards daybreak as the wind stabilizes to NE as the front pushes
offshore.

Extended Outlook... Restrictions possible through the weekend
due to daily shower chances from a stalled front. High pressure
building in late Mon into Tues should return dominant VFR.
-- End Changed Discussion --

&&

.MARINE...
Through Tonight...Sub-SCA conditions with a front stalled offshore
and deepening low pressure to our SW. Wind direction will be tricky
with the front in the area but SW winds during the AM hours will
turn to the NE during the evening, speeds near 10 kts increasing to
near 15 kts. Seas 2-3 ft with 4 footers creeping in late in the
period.

Sunday through Wednesday Night...Sunday morning should start
with a stalled front near Savannah, GA extending northeastward
across the open Atlantic Ocean. Low pressure should develop
along the front off the South Carolina coast during the day,
deepening only slowly as it moves out to sea Sunday night into
Monday. A surge of northerly winds will develop behind the
deepening cyclone, potentially approaching Small Craft Advisory
criteria Sunday night into Monday morning. I`ve added a couple
of knots to model blends as nearshore water temperatures have
risen well into the 60s and will contrast strongly with air
temperatures in the 50s much of the day.

Once this system departs the area Sunday night, a second area
of low pressure could develop well off the Georgia coast
Monday into Monday night. This could lead to lingering rain over
the coastal waters plus breezy northerly winds. Once we get into
Tuesday, this second low pressure system should be far enough
off the coast for winds to diminish with the approach of high
pressure from the west through Wednesday.

&&

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

&&

$$

SYNOPSIS...TRA
UPDATE...MBB
NEAR TERM...LEW
SHORT TERM...TRA
LONG TERM...TRA
AVIATION...MBB