280
FXUS62 KILM 150615
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
200 AM EDT Mon Jul 15 2024

.SYNOPSIS...
Above-normal heat and humidity will persist into midweek.
Afternoon showers and storms will remain isolated to widely
scattered through midweek until a front reaches down into the
Carolinas and stalls late in the week. The front should lift
back northward over the weekend and bring a return to more
typical summertime pattern.

&&

.UPDATE...
Convection continues to hang on inland with elevated
instability. Expect this to gradually come to an end over the
next couple of hours and provide some beneficial rain to
portions of Dillon County. Warm and humid overnight with many
areas already seeing dew points hit the 80 degree mark.

&&

.NEAR TERM /THROUGH MONDAY/...
Atlantic high pressure will edge in from the east while a
trough lingers inland. The upper high pressure system will
weaken a bit as it slides more to the southeast. However, we are
still expecting above normal temps to continue through the
period with lows mainly in the mid to upper 70s inland tonight
and highs Monday in the mid to upper 90s away from the immediate
coast. Dewpoints should mix out/lower inland during the day
Monday prior to the sea breeze passage but still should see peak
heat indices up to around 110 degrees most locales. Some spots
could more temporarily spike above 110 degrees but we don`t
think it`s enough to justify an Excessive Heat Watch/Warning at
this time. Thus, another Heat Advisory will likely be issued
later today once the ongoing Heat Advisory ends. Otherwise,
expect mainly isolated to widely scattered showers/storms into
this evening due to the sea breeze, inland trough and some weak
shortwave energy aloft, then again Monday afternoon.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
Mid-level ridging will remain in place through the period with
heights remaining generally steady. Surface high pressure east
of Bermuda will maintain a south to southwest flow as well,
which will bring a return of moisture back into the area in the
form of PWATS in the 2-2.25" range. Despite this, vertical
mixing on Tuesday and Wednesday should act to bring dew points
down into the lower 70s, with perhaps some upper 60s inland,
during the early to mid-afternoon. Most model guidance has been
over-forecasting dew points lately, and have opted to scale
these back in the short term by leaning on the GFS for this
period. In light of this, while Heat Advisory-level heat indices
remain possible, widespread heat indices exceeding 105F for
much of the day appear less likely in the short term.

Otherwise, diurnal pop-up convection looks to increase in
overall coverage on Tuesday and Wednesday as PWATs slowly rise
and modest capping diminishes. Nevertheless, with no notable
forcing mechanism besides the sea breeze and Piedmont trough, no
more than widely scattered development is expected, with perhaps
some focus near these two features. Otherwise, scattered fair-
weather cumulus can be expected. High temps are expected to
reach the middle 90s on Tuesday and low-mid 90s on Wednesday,
with greater low-level cloud cover and possibly more high-level
debris clouds expected to limit temps somewhat on Wednesday. Low
temps in the mid- upper 70s are expected each night.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
A significant shortwave trough is expected to pivot through the
Great Lakes on Wednesday into Thursday and continue across New
England over Thursday night and Friday. This will send a cold
front towards our region and bring decreasing mid-level heights
from Wednesday night into early Friday. With PWATs rising into
the 2.2-2.4" range ahead of this front, showers and
thunderstorms will be capable of producing very heavy rainfall
and localized flash flooding. Expect overall coverage of showers
and storms to increase with the approach of this front and the
lowering of heights, with Thursday and Friday seeming like the
best two days for scattered to potentially numerous storms
across the area. The ECMWF Extreme Forecast Index is showing
some signal for excessive rainfall across at least the northern
half of the area on Friday in association with this front,
particularly if it stalls near or over the CWA. The shortwave
driving this front lifts away and ridging noses back in from the
southeast after Friday, causing the front to stall out across
the Piedmont and lift back northward. Thus, have opted to cap
PoPs in the high chance range for the Saturday and Sunday
timeframe, but these may end up being too high if the front
indeed lifts well to our north over the weekend.

Temperatures will depend on the coverage of shower and storm
activity as well as their debris clouds which can limit or stop
heating during the mid-late afternoon. Thus, highs were held at
around 90F on Thursday and in the mid-upper 80s on Friday. High
temps on Saturday and Sunday are less certain as the coverage of
convection may be much more isolated while ridging builds back
in at the same time. So, the mid-upper 80s currently reflected
may be adjusted upward in future forecasts.

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
VFR to dominate this period. The exception will be possible periodic
restricted vsby from BR and low stratus ceilings, mainly across the
inland terminals. Boundary layer winds to remain active, keeping the
fog from worsening. Isolated/Widely scattered afternoon/evening
tstorms warrants atleast VCTS across all terminals, forcing from the
sea breeze and an inland sfc trof will be enough for this activity
to occur. Too soon to include specifics in regards to include PROB30
or TEMPO tstorm groups. Flow generqally SW to W around 5 kt this
morning, increasing to 10-15 kt at the coastal terminals once the
sea breeze develops and progresses inland midday thru this evening.

Extended Outlook... Atlantic high pressure will bring the return of
a more typical summertime pattern with diurnally-driven convection
with brief restrictions possible daily. VFR should otherwise
dominate outside of any early morning fog/low cigs. By Thu, a cold
front will drop into the Carolinas accompanied by an increase in
shower/storm coverage thru Fri.

&&

.MARINE...
Through Monday...Atlantic high pressure will edge in from the east
while a trough lingers inland. This will lead to fairly typical
summertime conditions with periods of higher winds, mainly from the
afternoon/evening sea breeze and nocturnal surging. However, winds
should mostly stay below 20 kt with seas 4 ft or less so we are not
expecting to need a Small Craft Advisory.

Monday night through Thursday...
Bermuda high pressure dominates the low-level flow through the
period, even with the approach of a cold front on Thursday.
South to southwest winds in the 10-20 kt range prevail with
gusts expected to mainly stay below SCA criteria. Waves will
remain elevated in the 3-4 ft range due to a combination of
decreasing southeasterly swell at 8-9 sec and increasing
southerly wind waves. The southeast swell is expected to
diminish through Thursday with heights of 2-3 ft on Monday night
decreasing to 1 ft or less by Thursday.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
NC...Heat Advisory from 10 AM to 8 PM EDT Monday for NCZ087-096-099-
     105>110.
SC...Heat Advisory from 10 AM to 8 PM EDT Monday for SCZ017-023-024-
     032-033-039-054>056-058-059.
MARINE...None.

&&

$$

SYNOPSIS...ILM
UPDATE...21
NEAR TERM...RJB
SHORT TERM...ABW
LONG TERM...ABW
AVIATION...DCH
MARINE...RJB/ABW