798
FXUS62 KILM 092027
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
427 PM EDT Thu May 9 2024

.SYNOPSIS...
A typical summer time pattern will lead to daily showers and
thunderstorms through Friday, sparked by a series of shortwaves
moving across the area. A cold front Friday night will bring
much cooler and drier air for the weekend and start of next
week. Rain chances increase by the middle of next week.

&&

.NEAR TERM /THROUGH FRIDAY/...
Atmosphere remained mostly stable today, with only a few rumbles
of thunder noted earlier this morning with the first wave of
convection left over from last night. Outflows dominated the
stability today, while the storms that moved through parts of
Georgia and South Carolina today pushed more southward than
eastward. As a result, the grand majority of the activity has
been limited to the CSRA and Lowcountry today. The other big
theme was the cloud cover putting quite the limit on
temperatures today, with only a few places reaching the lower
80s, while some only hitting the upper 70s.

Subsidence it already starting to take over again late this
afternoon, which will be the main idea going into tonight. Rain
chances will continue to taper off this evening, with a few
peeks at the stars likely late tonight. Lows in the upper 60s to
near 70 at the coast.

The coastal Carolinas remain well within the warm sector Friday
ahead of a cold front approaching from the west. Clouds and rain
chances are on the rise again. High-resolution guidance suggests
potentially two waves of showers and storms: One in the midday
to early afternoon, and the other in the late afternoon and
evening. This seems to make sense, as the first round is
associated with a shortwave that exits offshore of the Coastal
Empire and moves northeastward, while the second wave is
associated with the cold front itself. SPC paints the area in a
"Marginal Risk" (threat level 1/5) across the area. Shear and
helicity look roughly about the same as they have today, which
is overall decently favorable (more so the shear). Instability
may actually be more favorable, if it`s realized (SBCAPE could
be greater than 2000 J/kg in some spots). But we could be left
with the same situation as we have been today: Can the
atmosphere bust through the cap? High-resolution guidance
suggests the subsidence inversion sticks around Friday,
generally in the 850-700mb layer. This would seem to make sense,
based on the cloud cover that is expected, which is probably at
least partially the reason behind the risk only being marginal.
Confidence is shaky here, but it`s hard to look at what we saw
today and not see a similar situation play out for Friday (i.e.,
less severe weather). Need to see how much convective debris
will blow off of the MCS that is expected to push off Georgia
and Florida Friday morning. If severe weather is realized, large
hail and damaging winds would be the main threats in play once
again.

Highs Friday in the low-to-mid 80s.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
Cold front will be near the coast with a 5h trough lagging back to
the west Fri night. The trough quickly moves through, pushing any
lingering convection offshore and ushering in much drier air.
Precipitable water drops under 0.50" by daybreak Sat and will stay
under an inch through Sat night. There is a shortwave late Sat into
Sat night that drives a secondary cold front across the area. Lack
of moisture and subsidence ahead of these features will prevent any
rain and even cloud cover will be limited to some flat cu at the top
of the mixed layer (more likely to be altocumulus given the 8k ft
mixing heights) Sat afternoon and evening. Temperatures will run
several degrees below climo.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
Dry, secondary cold front will be offshore Sun morning as long wave
5h trough moves east of the area. The week will start off with a
very dry air mass in place and temperatures around climo. Center of
the high moves overhead Sun night into Mon and then offshore Mon.
Return flow develops as the high migrates east, rapidly increasing
deep moisture. Precipitable water jumps about an inch in 12 hours
Mon night into Tue with a warm front lifting north of the area
during Tue. Rain chances increase with the front and then remain
elevated Wed as a 5h trough moves across the area. The next system,
moving into the region later Thu may bring another round of showers
and thunderstorms in the afternoon and evening. Lows above climo Mon
night and well above Tue/Wed nights. Clouds and rain will keep highs
below climo Tue. A summer-like pattern returns for Wed/Thu with
highs running above climo.

&&

.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
VFR expected through most of the 18Z TAF period. Only isolated
showers in play at this time, with brief visibility restrictions
possible at KFLO and perhaps KCRE/KMYR over the next few hours.
Southwesterly winds will dominate this period, with gusts
subsiding after sunset this evening. Thinking it`ll be too
breezy for fog tonight, but low ceilings may develop after 06Z
tonight with another shortwave passing through. Confidence is
shaky on this idea, but some sites may go down to MVFR or even
IFR if the ceilings are realized.

Southwesterly winds may pick up again throughout Friday morning,
and showers and storms may start to threaten KFLO and KLBT
towards the end of the TAF period.

Extended Outlook...A cold front moves through Friday night,
which dries out the atmosphere. Widespread VFR should take over
Friday night through Monday. Flight restrictions may occur
Monday night into Tuesday with the next weather system moving
in.

&&

.MARINE...
Through Friday...Southwesterly winds maintain a hold through
Friday, with speeds decreasing at first tonight, and then
potentially gusting up to 20kts at times Friday afternoon. Seas
generally 2-4ft, with a southerly swell at 5-6 seconds. Look for
a secondary easterly swell of 1ft at 10-11 seconds.

Friday Night through Monday...Offshore flow develops Fri night
following the passage of a cold front in the evening. Speeds
around 20 kt will be possible after the passage of the front,
before dropping to 10-15 kt on Sat. Winds gradually back to
southerly in the afternoon, ahead of another front that will
cross the waters Sun morning. Weak offshore flow redevelops
behind the front then gradually becomes onshore Mon as the sea
breeze drives the wind field. Seas 3-4 ft Fri night drop to 2-3
ft Sat through Mon. The wind wave will be the dominant wave with
a weak easterly swell present into the start of next week.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
NC...Coastal Flood Advisory from 10 PM this evening to 2 AM EDT
     Friday for NCZ107.
     High Risk for Rip Currents until 8 PM EDT this evening for NCZ110.
SC...None.
MARINE...None.

&&

$$

SYNOPSIS...ILM
NEAR TERM...IGB
SHORT TERM...III
LONG TERM...III
AVIATION...IGB
MARINE...III