162
FXUS62 KILM 190029
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
829 PM EDT Thu Jul 18 2024

.SYNOPSIS...
Showers and thunderstorms will move in ahead of a cold front
tonight. The front will linger near or north of the area
through the weekend. Rain chances will remain elevated through
Monday with temperatures running near to slightly below normal.
Unsettled weather may continue into early next week.

&&

.UPDATE...
Forecast is largely on track at this point. The cold front is
just north of the local forecast area, with a broken line of
showers and storms ahead of it. Outflow from the storms is
outrunning the front more and more, as expected. Storms should
be reaching coastal areas north of Cape Fear within the next
couple of hours, with the Grand Strand coast lagging about an
hour or so. Some of these storms could become strong at times,
with 40-45 mph wind gusts and small hail. High rainfall rates
may lead to ponding or nuisance flooding, particularly if the
stratiform shield behind the main line slows over a particular
area.

Elsewhere, updated 00Z TAF discussion found below.

&&

.NEAR TERM /THROUGH FRIDAY/...
Thus far have seen minimal development of convection across the
local area, but this should change later this evening as weak front
and the remains of the Piedmont trough move in from the northwest.
Scattered convection developing along the front across the central
Carolinas will move southeast, accelerating ahead of the boundary
and reaching the forecast area by early evening. Some isolated
storms will bubble up along any surface boundaries (ie seabreeze and
Piedmont trough) the next few hours, but more widespread and
stronger storms will be the ones moving in from the northwest. Any
well developed storms will have the potential to produce significant
rainfall, with a deep warm cloud layer and precipitable water values
around 2.25" in the afternoon and evening. Storm motion of 15-20kt
will limit flooding potential, but localized flooding, mainly in
typical prone areas, will be possible given the high rainfall rates.
Cannot rule out a couple severe storms, but most of the convection
will remain sub-severe.

Front sags into the area overnight, reinforcing the already moist
airmass. Despite the front in the area, boundary winds will be
strong enough to keep stave off significant fog development.
Lingering debris cloud, low level winds and moisture will continue
the stretch of overnight lows above climo.

Most of the environmental conditions Fri will be similar to today.
High pwats, deep warm cloud layer, and CAPE 2k-3k J/kg. However,
there will be a few significant differences. The weakening front
will be stalled in or near the area and storm motion will drop
closer to 10kt. The presence of the boundary within a very
moist/unstable environment should lead to higher coverage of
convection and an earlier start to the storms. Increased cloud cover
will lead to cooler temperatures. Cooler temperatures coupled with
weaker winds and lower shear will curtail any severe weather threat,
but the high efficiency of the storms coupled with their slow
movement will increase the potential for flooding.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
By the start of the period, a stationary front should be stalled
near the coast. A shortwave looks to pass to our NW late Fri into
early Sat, with localized low pressure forming along the boundary at
the surface. Shower/storm coverage will be enhanced overnight with
higher coverage shifting towards the coast during the day Saturday.
PWATs will be near 2-2.5" with soundings showing the warm cloud
layer 10000-13000 ft. Localized flooding could be possible due to
how moist the environment will be.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
Unsettled weather holds through the long term period. Ridging will
build overhead with vorticity skirting around the CWA, the pattern
of showers/storms looking more diurnal in nature with lower POPs
overnight increasing in the afternoon/evening near the Piedmont and
at the coast. Temps will be fairly steady day to day and near normal.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
Mostly VFR to open the 00Z TAF period, with exceptions. A line
of showers and storms ahead of a cold front is moving through
the area, affecting KFLO and KLBT to open the period. This line
should make it to KILM by 02-03Z, while KCRE/KMYR may linger an
hour or so behind. MVFR to IFR restrictions expected within
TSRA. MVFR and even IFR ceilings may linger in the wake of the
storms overnight, especially inland. Fog will be less of a
concern given the strength of boundary layer winds, although
brief MVFR visibility cannot be ruled out. Front will be in the
area Friday, which should lead to increased coverage of showers
and thunderstorms as well as an earlier start time. It could
very well be that storms develop before 18Z, but holding off on
that idea for now. PROB30 groups represent TSRA timing after 18Z
Friday.

Extended Outlook...Potential for afternoon and evening MVFR/IFR from
showers and thunderstorms each day.

&&

.MARINE...
Through Friday...
Southwest flow will continue through Fri but speeds will begin
decreasing as the gradient relaxes a bit. The combination of
cooler temperatures inland and the approach of the weakening
surface boundary will drop winds from 15-20 kt this afternoon to
10-15 kt tonight and Fri. While some gusts in excess of 25 kt
will remain possible through the evening hours, have no plans
for any headlines. Seas will trend down, dropping from 4-5 ft
today to 3-4 ft tonight and 2-3 ft Fri. The southerly wind wave
will remain dominant, although it will start to weaken Fri. A
southeast swell will also be present.

Friday Night through Tuesday...
South to southwest flow will remain dominant with speeds 10-15
kts remaining sub-SCA thresholds. Seas will be 2-3 ft with an
increase to 3-4 ft late Saturday through the end of the period
as the 8-10 seconds SE swell increases.

&&

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

&&

$$

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