636
FXUS62 KILM 131807
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
207 PM EDT Sat Jul 13 2024

.SYNOPSIS...
A lingering front over the Coastal Carolinas will get washed out
as Bermuda High Pressure takes control into next week, bringing
very hot weather and spottier rain chances. A cold front will
bring more substantial rain to the area Wednesday night into the
latter half of the week.

&&

.UPDATE...
Main changes with this update were to lower PoPs for the
remainder of the day. Between mid-level dry air and subsidence
keeping cumulus clouds small and flat across inland areas and
mid-level warming and high cirrus from earlier storms advecting over
the Grand Strand through Cape Fear regions, it seems that it
will be hard to get anything notable going across the majority
of the forecast area. The best chances for showers and storms to
pop up lie along and near the sea breeze in our SC zones, where
west to northwest flow enhances convergence along the sea
breeze and the mid-level warming induced by earlier convection
should stay generally to the east. As plenty of moisture remains
in place, locally heavy rainfall remains possible with any
shower or storm.

&&

.NEAR TERM /THROUGH TONIGHT/...
Showers and thunderstorms shifted their focus toward the coast
and offshore as lingering front shifted east overnight. Fog
developed inland, especially over the Pee Dee region with vsbys
below 1 mile in places. A very moist airmass will remain in
place through today although some drying will take place from
west to east winds above the sfc shift to a more westerly
direction.

Wave of low pressure running up along the front will move
off to the north and east leaving most activity off the coast as
ridge builds in aloft and front becomes more diffuse with
Bermuda High taking control tonight into Sunday. Models show
less activity for the most part today and with westerly flow
aloft, best convergence will be along the coast and any storms
will be driven toward the coast and offshore along with debris
clouds this morning. The air mass remains loaded with pcp water
values still over 2 inches through much of today but dropping
below 2 inches into early Sunday. Expect greatest rain chances
through this morning, mainly along the coast but the combination
of the weakening front inland and local effects should provide
a focus for shwrs/tstms inland into this afternoon with greater
instability as diurnal heating takes place.

Once fog and low clouds lift, expect some cu and shwr development
but also should see increasing sunshine from west to east,
especially across inland areas. Temps will reach into the low to
mid 90s as sunshine increases across inland areas. Heat index
values will reach up above 100 and just shy of heat advisory
criteria across inland SC where sunshine will be most plentiful.
Temps tonight will remain in the mid 70s most places with
readings near 80 just along the coast for lows tonight.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
The deep moisture plaguing the ILM CWA the days prior will get
shunted offshore from the NC and SC Coasts this period due to W
to WNW winds aloft resulting from ridging aloft across the SE
States. Unfortunately that means the heat will return with a
vengeance. Looking at Heat Adv criteria Sun and Mon with the
possibility of borderline excessive heat warning thresholds
being met Mon. Could even observe max temps at or above the
triple digit mark, mainly well inland in the vicinity of the
I-95 corridor. Will still "enjoy" the tstorm threat each day but
will mainly be diurnally driven convection ie. starting late
morning at the coast due to the developing sea breeze followed
by it`s aftn/evng push inland along with the associated
convective activity. Overall POPs will run in the low to
possibly modest chance at the mentioned times. Any nocturnal
Atlantic convection should remain over the waters Sun night and
Mon Night given offshore wind directions aloft.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
Worse of the heat may be Tue with the potential for Excessive
Heat Warning thresholds being met across a large percentage of
the ILM CWA. Convection chances will be held to low chance,
primarily driven by the sea breeze with ridging and warm temps
aloft suppressing convection potential. Once again triple digit
max temps possible Tue, well inland. The sea breeze won`t
provide any relief, although it may lower temps after its
passage but dewpoints (humidity) will increase after its
passage. And may actually further increase heat indices. For late
Tue thru Wed, the weak upper ridging breaks down with flow aloft
becoming SW allowing for increasing moisture thru the atm
column. Piedmont trof and the sea breeze Wed will both provide
forcing for increased tstorm activity with POP at good chance in
the offering. Add a cold front slowly dropping south and
stalling in the vicinity Thu thru Fri and we will observe more
clouds and hier POPs each day. Look for temps to drop to more
respectable/normal levels. Night-time lows Tue night and Wed
night may struggle to fall below 80 degrees, especially at the
coast.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
MVFR to VFR cigs are expected to prevail through the remainder
of today as cumulus clouds continue to develop amidst the
warming of a very moist air mass. Have opted to remove TS
mentions in prevailing groups across the area as a mix of mid-
level subsidence inland and mid-level warming from earlier
storms near the coast should act to keep a lid on convection. At
the Grand Strand terminals, surface convergence of very warm
and moist air into the sea breeze should result in at least
isolated convective development through mid-late afternoon as
temps rise into the lower 90s away from the coast, and have
opted to include a PROB30 group to account for this. Tonight,
winds should become light and variable inland while winds remain
out of the south to southwest overnight at the coastal
terminals. While low-level moisture will remain high and skies
should end up generally clear, confidence in mist is low for
tonight at inland terminals as forecast soundings suggest that a
15-20 kt low-level jet will develop, allowing for occasional
mixing to keep fog at bay. Nevertheless, brief MVFR mist may
develop overnight during periods of light or calm winds.

Extended Outlook...High pressure will bring the return of a more
typical summertime pattern with pop-up convection and attendant
brief restrictions possible daily. VFR should otherwise dominate
outside of any early morning fog/low cigs.

&&

.MARINE...
Through tonight...Southerly winds will veer to the SW and
diminish as lingering front over the Coastal Carolinas weakens
and Bermuda High begins to dominate again into early Sunday. The
gradient flow will weaken allowing seas to drop below SCA
thresholds this morning. SCA still holds until 7am and will
assess then and make sure seas are below 6 ft to take down Small
Craft Advisory then. Winds and Seas will be falling to 3 to 5
ft in northern waters and then down to 3 to 4 ft tonight into
Sunday. A southeasterly 8 second swell will mix in through
today.

Sunday through Wednesday...
Bermuda ridging sfc/aloft will build/extend to Florida Sun thru
Tue, resulting in SW wind directions becoming dominant across
the waters. By late Wed, winds may back to a more SSW-S
direction ahead of an approaching cold front and with Bermuda
high pressure slightly retreating. Wind speeds generally 10-15
kt, g20 kt nearshore each aftn/evng Sun thru Tue. By Wed, sfc pg
tightens resulting in a solid 15 kt or 15-20 kt speed. Seas,
power-wise, will generally be dominated by a SE swell at 7 to 9
second periods with a SW wind chop on top. That may change by
Wed as SW wind chop increases in height. &&

.TIDES/COASTAL FLOODING...
Other - Rip Currents: There is a high risk of rip currents for
Modest SE swell at 7+ second periods, resulting in a High Rip
risk likely for 1 more day across the beaches of Pender/New
Hanover counties. Moderate rip risk will continue elsewhere with
this SE swell slightly lower when compared to Cape Fear
northward. This SE swell will decay some by Sun, dropping to
around 3 ft and holding at this height with periods slightly
increasing by 1 or 2 seconds into early next week. This will
likely keep atleast a moderate rip risk for most if not all
beaches going into next week.

&&

.TIDES/COASTAL FLOODING...
Other - Rip Currents: There is a high risk of rip currents for
There is a high risk of rip currents for the beaches of
Pender/New Hanover counties resulting from a modest SE swell at
7+ seconds. Moderate rip risk will continue elsewhere with this
SE swell slightly lower in height when compared to Cape Fear
northward. This SE swell will decay some by Sunday, dropping to
around 3 ft and holding at this height with periods slightly
increasing by 1 or 2 seconds into early next week. This will
likely keep at least a moderate rip risk for most if not all
beaches going into next week.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
NC...High Risk for Rip Currents until 8 PM EDT this evening for NCZ106-
     108.
SC...None.
MARINE...None.

&&

$$

SYNOPSIS...ILM
UPDATE...ABW
NEAR TERM...RGZ
SHORT TERM...DCH
LONG TERM...DCH
AVIATION...ABW
MARINE...DCH/RGZ
TIDES/COASTAL FLOODING...