022
FXUS62 KILM 240142
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
942 PM EDT Thu May 23 2024

.SYNOPSIS...
Shower and thunderstorm chances will grow as a series of
upper level disturbances move across the region Friday through
Sunday, while a front remains stalled well north of the area.
Inland temperatures will rise into the lower 90s by Sunday,
then cool back towards normal by Wednesday behind a cold
frontal passage late Tue.

&&

.UPDATE...
Have tweaked POPs across the CWA slightly lower and pulled
slightly back the further southward extent and coastal extent
based on latest 88D trends and the latest hi-res models. Will
see debris convective mid and upper level clouds moving and
slowly partially scouring out-some as the overnight progresses
into daylight Fri. Very little tweaking needed for overnight
lows. Marine winds generally SW around 10 kt or 10-15 kt as
night time SW winds 15 to 20 kt just off the deck mix down-
some. Seas generally around 2 ft, with an underlying easterly
swell at 8 to 10 second periods dominating with wind chop above.
Could see a solid SW 15 kt near shore Fri as seen today due to
the sea breeze.

&&

.NEAR TERM /THROUGH FRIDAY/...
A ridge axis extending northeastward from a mid and upper
level high centered over the Gulf of Mexico will move off the
Carolina coast this evening. Behind this ridge the westerly flow
near and above 700 mb will bring cooler air overhead, removing
the convective cap that has remained across the Carolinas for
the past several days. Precipitable water along the coast should
increase from around 1.2 inches this morning to 1.8 inches by
Friday morning. A series of upper level disturbances should
begin to arrive tonight, each potentially accompanied by a wave
of showers and thunderstorms.

Timing of these disturbances starts easy but gets more muddled
with time. Disturbance #1 is discernible in water vapor imagery
now across central TN into Alabama and should move across the
eastern Carolinas tonight. My forecast shows an increasing trend
in inland PoPs after 9 PM, peaking around 40 percent late in
the evening, then diminishing again after 1 AM. It`s less likely
this initial wave will reach the coast intact although clouds
should certainly increase. Forecast lows are generally in the
upper 60s inland to around 70 on the coast.

Mesoscale subsidence behind tonight`s initial impulse may keep
convection isolated Friday morning, but renewed convective
activity should develop during the afternoon hours as surface-
based instability rises to near 2000 J/kg and modest DPVA
overspreads the region in advance of another disturbance slowly
approaching from the west. High-res models suggest the seabreeze
front should be a significant trigger for convection, and my
forecast PoPs are highest (60 percent) just inland from the
coast. Forecast highs are in the upper 80s, except lower-mid 80s
at the beaches.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
Still expecting an active pattern for the weekend via the
mostly zonal mid level flow and embedded short waves. Of course
the inland Piedmont Trough and to a lesser extent the sea breeze
will play a part as well. The highest pops occur Friday night
and again Saturday pm. Guidance is trending toward formidable
NVA in the wake of Saturday`s system for Sunday and pops may
need to be reduced further there if this continues. Temperatures
look to remain above climatology throughout.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Active pattern continues for the first part of next week as the
west to east mid level flow pushes to the south slightly with
remaining embedded shortwaves. It appears the best forcing in
several days may occur Tuesday evening when all of the elements
(surface front, mid level height falls) combine. Beyond this
still expecting dry conditions to develop along with cooler
temperatures.

&&

.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
An upper level disturbance to approach from the west overnight
into Fri. Have indicated a VCTS/VCSH for the inland terminals
by 04z/05z with activity likely dissipating as it pushes closer
to the coast during the pre-dawn Fri hrs. Could see a round of
low stratus around a 2-3 hr window around sunrise. A better shot
of convection from generally 18Z Fri thru the remainder of the
fcst period. May use PROB30 groups to highlight at this time
given the upper disturbance, the sea breeze and says insolation
aiding increasing instability.

Extended Outlook...Scattered thunderstorms will be accompanied
by periodic short lived MVFR/IFR conditions through the weekend
into Monday. The best potential appears to be Friday and
Saturday afternoons when thunderstorm potential coverage and
potential increases at or above 50 percent, especially inland.

&&

.MARINE...
Through Friday...Surface high pressure will retreat east to
near Bermuda tonight as a series of weak upper level
disturbances begin to move across the Carolinas from the west.
Synoptic winds will remain south to southwest at less than 10
knots, however some higher winds will persist along the coast
through this evening due to today`s well- defined seabreeze
circulation. Additional periods of stronger winds could
accompany scattered thunderstorms on Friday, expected to be
most numerous during the afternoon hours. A few of our high-res
weather models including the HRRR explicitly indicate west to
northwest thunderstorm outflow winds developing along the South
Carolina coast late Friday afternoon.

Outside of any thunderstorms, sea heights of only 2 feet are
expected through Friday consisting of an eight second easterly
swell plus local wind chop.

Friday night through Tuesday...Overall light winds will persist
into the weekend from the south to southeast as the pressure
pattern remains weak. In time the flow will turn more from the
southwest and increase a bit in magnitude. This occurs early
next week. Significant seas will be 2-3 feet this weekend
perhaps increasing to a range of 2-4 feet early next week.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
NC...Coastal Flood Advisory until 1 AM EDT Friday for NCZ107.
SC...None.
MARINE...None.

&&

$$

SYNOPSIS...DCH
UPDATE...DCH
NEAR TERM...TRA
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...DCH
MARINE...TRA/SHK