-- Discussion containing changed information from previous version are highlighted. --
213
FXUS62 KILM 301752
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
152 PM EDT Sun Jun 30 2024

.SYNOPSIS...
One more hot and very humid day is expected today before a cold
front arrives tonight and Monday with increased coverage of
showers and thunderstorms. Relatively cooler and drier
conditions will develop behind the front on Tuesday. Stifling
heat and humidity should return late in the week.

&&

.NEAR TERM /THROUGH TONIGHT/...
A weakness between two mid-level anticyclones will allow a shortwave
to dive southeastward and bring unsettled weather across the region,
especially during the latter half of the period. Prior to this, weak
flow through the troposphere and the remains of mid-level dry air
and subsidence should keep overall convective coverage today in the
isolated to widely scattered category, with some focus along the sea
breeze. Further inland, height falls and subtle cooling/moistening
aloft should support a greater coverage of showers and
thunderstorms, initially forming into one or more lines along the
Piedmont trough to our northwest and spreading southeast late in the
afternoon and into this evening. Given the very moist environment
characterized by PWATs in the range of 2-2.5", very heavy rainfall
may cause isolated flash flooding and isolated wet microbursts may
produce wind damage in the strongest storms. As nocturnal cooling
commences and surface-based convective inhibition increases while
instability decreases, an overall decline in storm coverage and
intensity should take place, although isolated showers and storms
forming along remnant outflows will remain possible through the
first half of the night (through around 06Z).

Later in the night (mainly after 08Z), the cold front itself, in
tandem with forcing for ascent provided by the incoming shortwave,
should yield an uncharacteristic increase in shower/storm coverage,
with the most widespread activity expected to develop and track
southward through the Cape Fear region and more scattered activity
in the Pee Dee region. With long, skinny CAPE profiles seen in
forecast soundings, overall storm intensity should be tame, but very
heavy rainfall and isolated flash flooding will be a threat.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
An unusually strong upper disturbance (for July standards) will
dive southeastward across the Northeast states Monday, pushing
a cold front southward across the Carolinas. The front should
intercept a very humid airmass with precipitable water values up
to 2.5 inches. Widespread showers and thunderstorms should be
ongoing Monday morning and will follow the front southward
throughout the day. The potential for heavy rainfall exists with
high freezing levels and deep warm cloud coalescence expected
to occur. Weak low level lapse rates should limit the
probability of severe weather.

The airmass should dry out from the top down behind the front
Monday afternoon into Monday night with precipitation largely
ending away from the South Carolina coast. Northeast winds will
bring gradually drier air in and dewpoints by sunrise Tuesday
morning could be in the 60s all the way down to Georgetown, SC.
Not exactly "open the windows" kind of weather but better than
the upper 70s dewpoints we`ve dealt with for most of the past
week.

Highs Monday and Tuesday should be limited to the lower to
middle 80s with nighttime lows falling in the 60s away from the
beaches.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
The subtropical ridge should build almost directly across the
Carolinas Wednesday through Friday leading to surging
temperatures. Surface high pressure located well offshore should
resume southerly winds again which will advect a fully tropical
airmass back across the Carolinas. The combination of
temperatures rising well into the 90s inland plus dewpoints in
the 70s should lead to heat indices rising above 105 degrees by
Friday.

By Saturday, 00z operational runs of the models diverge with
the specifics surrounding an upper trough that tries to cut off
between the Southeast Coast and Bermuda, but upper ridging will
almost certainly remain intact near the Carolinas. A second day
of sultry heat and humidity could push heat indices above 110
degrees. This is the level where we would transition from a
"heat advisory" to an "excessive heat warning" so watch the
forecast closely for Saturday.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
-- Changed Discussion --
All sites currently VFR but some challenges are ahead. A
couple of rounds of showers and thunderstorms will move across later
this afternoon and overnight with more confidence with FLO and LBT
seeing sustained thunder and addressed with tempo groups. Thunder
and even overall activity are more uncertain across coastal areas as
the cold front/pre frontal trough takes some time to move across
perhaps losing instability and or intensity. Addressed this scenario
with VCTS. Ceilings should dip to MVFR late (maybe isolated IFR) in
the period/early Monday morning in the wake of the main activity.


Extended Outlook...The approaching cold front will bring low
cigs to all terminals on Monday and scattered to numerous
showers and storms through the day, with the highest confidence
at the coastal terminals. Depending on how far south the front
reaches, brief MVFR cig or vis flight restrictions may occur at
times well into Monday night for the coastal terminals.
Otherwise, for Tuesday through Thursday, VFR should dominate.
-- End Changed Discussion --

&&

.MARINE...
Through Tonight...An approaching cold front will bring an increase
in southerly flow over the waters today with speeds of 10-15 kts and
gusts near 20 kts this afternoon and evening. Winds gradually veer
to southwesterly late in the night as the front draws near. Waves
around 2 ft this morning increase to 3 ft this afternoon in light of
the stronger southerly flow and some 4 footers may be observed in
the outer waters off Cape Fear near 20 nmi. Southerly 1-3 ft wind
waves and 1-2 ft ESErly 8 sec swell will be the main contributors to
the wave spectrum today. Numerous showers and thunderstorms are
expected to affect the waters starting very late tonight as a cold
front nears from the north.

Monday through Thursday Night...All models show a strong cold
front (by July standards anyway) moving through from the north
Monday. Southwest winds should shift northeasterly during the
day as the boundary drops south, accompanied by widespread
showers and thunderstorms. Gusty winds and reduced visibility
in heavy rain will be possible in storms. The front should make
it down to near the FL-GA state line Monday night before
stalling. A period of breezy northeast winds 15-20 knots is
expected behind the front here Monday afternoon continuing into
Monday night before slowly veering easterly and diminishing in
speed Tuesday through Wednesday.

Although not explicitly shown in the forecast, it would only
take a few more knots of wind to reach Small Craft Advisory
criteria Monday night. As it stands now, growing wind chop
behind the front should increase sea heights to 4-5 feet Monday
night. Long fetch lengths on easterly winds Tuesday and
Wednesday will lead to only a slow reduction in seas although
wave periods should lengthen with time as swell becomes more
dominant. It`s also worth mentioning that small but very long
period swells from Hurricane Beryl could arrive as early as
Wednesday night with wave periods around 15 seconds shown in the
latest model guidance.

&&

.FIRE WEATHER...
Although there has been isolated heavy rainfall in spots over
the past few days, the current U.S. Drought Monitor shows moderate
drought (D1) exists across portions of eastern North and South
Carolina. This drought has developed due to 60 day rainfall
totals running well below normal plus recent hot, dry weather.
Widespread soaking rain appears possible with tonight and Monday`s
frontal passage with 1 to 2 inch totals forecast. Hot and dry
weather should redevelop late in the week and may continue
through July 4.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
NC...Heat Advisory until 7 PM EDT this evening for NCZ087-096-099-
     105>110.
SC...Heat Advisory until 7 PM EDT this evening for SCZ017-023-024-
     032-033-039-054>056-058-059.
MARINE...None.

&&

$$

SYNOPSIS...TRA
NEAR TERM...ABW
SHORT TERM...TRA
LONG TERM...TRA
AVIATION...SHK
MARINE...
FIRE WEATHER...