-- Discussion containing changed information from previous version are highlighted. --
531
FXUS62 KILM 271502
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
1102 AM EDT Thu Jun 27 2024

.SYNOPSIS...
Hot and humid conditions will continue through the weekend. Two
cold fronts will move into the region on Thursday and late
Sunday bringing increased chances of thunderstorms. Unseasonably
hot temperatures will temporarily cool back to normal early
next week.

&&

.UPDATE...
-- Changed Discussion --
Low clouds around this morning have transitioned into cu this
morning. Have adjusted temps down a bit due to a mix of low and
high clouds. Best chc of Heat Advisory conditions with heat
index values reaching over 105 will be closer to the coast, but
a bit tricky. Remain in pre-frontal unstable atmosphere and
looks like first storms may develop around 2 pm or so and then
best chc of svr between 3 or 4 pm to 9p.
-- End Changed Discussion --

&&

.NEAR TERM /THROUGH TONIGHT/...
Onshore flow and pre-frontal warming will bring hot and humid
conditions again today. A heat advisory has been issued for all
areas east of I-95. The exclusion of counties west of I-95 is due to
the development of afternoon convection. Hi-res models vary slightly
on when convective initiation will occur this afternoon. Most of
these areas are likely to see storms around or prior to 3 PM which
would cap afternoon temperatures. There is some uncertainty for
areas to the east as outflow expands eastward with the cold front.
Areas near the coast will see heat indices in excess of 105 degrees.

SPC has maintained a Marginal Risk (level 1 of 5) for severe weather
this afternoon. Widespread showers and storms are expected with a
cold front. Ample instability and weak shear will produce an
environment capable of producing a strong or damaging wind gust.

Exiting upper level shortwave will bring a quick end to any
remaining daytime convection over land. Subsidence following the
shortwave and added soil moisture could lead to areas of fog on
Friday morning. Lows in the low to mid 70s.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
As the shortwave responsible for sending the cold front towards
our area shears out and drifts southeastward on Friday morning,
the front is expected to stall out over the area and lift back
northward on Friday. Winds initially out of the east in the
morning will veer to southeasterly in the afternoon. This will
keep the lower atmosphere moist and allow for at least weak
instability to develop as daytime heating progresses. However,
with mid-level ridging nosing in behind the shortwave trough,
dry air and subsidence will come into play and help keep
convective coverage in check. Highs should still reach the lower
90s with perhaps some mid-90s in spots; the main limiting
factor will be the amount of debris clouds associated with
convection. The loss of daytime heating should bring most
showers and storms to an end during the first half of Friday
night with overnight lows in the mid 70s.

On Saturday, mid-level ridging remains in place with its
associated subsidence inversion and dry air holding firm around
and above 600mb. Similar to Friday, this will keep convective
coverage in check, and with the front out of the picture, it
appears lesser overall coverage is in store, with the main
focus being near the Piedmont trough. Highs should get a little
warmer than on Friday due to the lack of notable forcing
mechanisms, with low-mid 90s expected. Heat Advisory conditions
(>=105F heat indices for at least 2 hrs) are possible on this
day given that dewpoints remain in the middle 70s. During the
evening and overnight, any convection should quickly wane with
the loss of daytime heating and lows should end up in the mid-
upper 70s.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
The mid-level pattern gets more interesting on Sunday as
a rather potent shortwave dives southeastward across the Great
Lakes, driving a cold front southeastward ahead of it. Moisture
pooling ahead of the front looks to drive PWATs up to around 2
standard deviations above normal on Sunday, yielding values of
around 2.25", which means a juicy airmass capable of producing
very heavy rainfall will be in place. Before any storms
develop, highs could reach the mid-90s, resulting in another day
where at least Heat Advisory conditions are reached. Diurnal
convective coverage may be enhanced by the approaching front,
although this may not happen until late in the afternoon or in
the evening. With the approaching shortwave keeping height falls
going overnight, this should keep convection alive well into
the night, although the overall intensity should decrease as
instability wanes. Nighttime lows in the low-mid 70s are
expected.

On Monday, the front is expected to be over the area gradually
pushing southeastward. As daytime heating gets underway, another
round of heavy showers and thunderstorms seems possible,
especially along and south of the front. Eventually, the
boundary should move south of the area during the night, with
cooler and drier air filtering in behind it for Tuesday morning.
Unfortunately, this relief will be short-lived as the mid-level
trough shifts away and ridging builds back in, resulting in a
warming and moistening trend commencing on Wednesday.

&&

.AVIATION /15Z THURSDAY THROUGH MONDAY/...
Low clouds at LBT this morning appears to be the only reliable
flight restriction. This is due to a pre-frontal trough pushing
low clouds and westerly winds through parts of central NC.
Expect this to be brief and southerly flow to become re-
established late this morning or early this afternoon with VFR
returning.

VFR elsewhere this morning, even along the coast where SW flow
is keeping MVFR stratus east of the terminals. There is a chance
that these clouds will attempt to push inland this morning and
again late this morning when southerly flow become dominant.

Models have been a little more consistent over the last couple
of hours regarding the timing of thunderstorms and the potential
for severe weather this afternoon. In general, expect
thunderstorms to reach western areas around 19Z and gradually
push toward the coast through this evening. Have included TEMPOs
for heavier storms, with general -TSRA before and after. Timing
should become clearer by the 18Z issuance. Frontal passage this
evening will create variable wind directions and enough momentum
where VRB at 4-6 knots is possible at times. Main uncertainty
will be along the coast where the frontal boundary and outflows
from storms over the ocean will be competing. Fog likely
inland tonight with calm winds behind the front.

Extended Outlook...VFR should prevail outside of periodic
MVFR/IFR during diurnal showers/thunderstorms plus spotty
morning low clouds/fog.

&&

.MARINE...
Through Tonight...
Onshore flow this morning will shift slightly ahead of a cold
front this afternoon. Seas will increase to 3-4 feet. Widespread
showers and thunderstorms will develop late this afternoon and
this evening and are likely to continue for at least part of the
overnight period. Outside of convection, winds will be light
tonight behind the front, varying in direction. Light and
variable winds continue through Friday morning before onshore
flow becomes re-established later in the day.

Friday through Monday...
With a cold front stalling overhead then lifting back northward
on Friday, initially easterly winds turn southeasterly then end
up at southerly by Saturday morning. Southerly flow remains in
place and increases ahead of another front on Sunday. The
arrival of this front should bring extensive shower and
thunderstorm coverage to the waters for Sunday night through
Monday. Eventually, the front settles through with east to
northeasterly winds taking over late on Monday. Seas look to
hold steady in the 2-3 ft range with an ESE 1-2 ft swell at 8-9
sec and southerly 1-2 ft wind waves at 4-5 sec in place through
the period.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
NC...Heat Advisory until 6 PM EDT this evening for NCZ087-096-099-
     105>110.
SC...Heat Advisory until 6 PM EDT this evening for SCZ024-032-033-
     039-054>056-058-059.
MARINE...None.

&&

$$

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