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FXUS62 KILM 211904
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
304 PM EDT Thu Sep 21 2017

.SYNOPSIS...
Isolated showers and storms can be expected through Friday as
an upper trough lingers over the region. Seasonably warm and
dry weather will prevail this weekend into next week, as an
upper ridge expands over the area. Tropical storm Jose spinning
off the New England coast will remain nearly stationary, but is
expected to weaken through the period. Hurricane Maria will
curve to the north, remaining east of the Bahamas Friday and
Saturday, passing offshore of the Carolinas Monday through
Wednesday of next week.

&&

.NEAR TERM /THROUGH FRIDAY/...
As of 3 PM Thursday...Showers and storms dotting the radar as
anticipated with a fairly high degree of randomness...only a
slight  concentration along the NC seabreeze (though little
activity in coastal SC where cu fields first blossomed). Being
fueled by the pairing of cold temperatures aloft and our very
warm afternoon this activity will wane towards sunset, though
perhaps slower than normal due to the very steep lapse rates
these temperatures have yielded. The upper trough and cold pool
linger into tomorrow albeit in a weakening state. Isolated
showers and storms once again with fairly random coverage
expected.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
As of 3 PM Thursday...Weak mid level troughing aloft remains in
place through the period while surface high over the eastern
Great Lakes builds south. This pattern tends to support weak
diurnal convection, however mid level dry air and subsidence
will keep the region dry for much of the period. The only
exception will be possibility of diurnal convection lingering
into Fri evening. There is not really any shortwave energy
driving the convection on Fri and this should lead to activity
weakening with the loss of heating. Temperatures will run well
above climo with the exception being along the coast where highs
will only end up a few degrees above climo due to the sea
breeze/northeast low level flow.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
As of 3 PM Thursday...A pleasant, seasonably warm and dry
extended forecast in the cards, provided no surprises arise in
the projected forecast track of Hurricane Maria, who is slated
to pass slowly north but well offshore of the Carolinas Monday
through Wednesday of next week. Aside from this, a pronounced
upper ridge will dominate the synoptic pattern, providing the
warm and mainly dry weather. Cross-sectional analysis through
time shows exceptionally dry mid-level air through the long
range period, keeping pop values very low, in the isolated to
none category. The exception will be very late or just beyond
the period next Friday, when a highly amplified upper trough
begins to drop SE toward the East coast. This will begin to
increase rain chances, while associated shear aloft begins to
guide Maria off to the NE away from the Mid-Atlantic coast.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
As of 18Z...Showers developing at this hour and they are
expected to generate lightning within an hour or two. They
will be very spotty in nature and never last long over a given
location and so have relegated to VC all terminals. Activity
will drop off or cease altogether around sunset. Most places
will probably have bouts of MVFR visibility late tonight. Lower
vis and perhaps even ceilings will be possible should any area
see more substantial rainfall.

Extended Outlook...Mainly VFR conditions through the period are
expected with the exception of a few hours of early morning low
clouds or fog most mornings through the period. The highest
risk of IFR conditions will be in the 0900-1200Z timeframe each
morning.

&&

.MARINE...
NEAR TERM /THROUGH FRIDAY/...
As of 300 PM Thursday...Pretty minimal conditions over the
marine environment. There is no well defined piedmont trough and
the normal west Atlantic high is disrupted and displaced by the
circulations of Jose and Maria. Spectral wave plots still show a
predominant swell but dominant wave heights will continue to be
the diminutive wind wave through the period.

SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
As of 300 PM Thursday...Winds will remain northeast through the
period as surface high over the eastern Great Lakes builds
south. Gradient will start to tighten a little later in the
period as Hurricane Maria moves closer to the region. Speeds
should be under 10 kt through Sat before increasing to 10 to 15
kt Sat night. Swells from Maria will begin reaching the waters
late Fri or Fri night with seas building through much of the
period. Small craft headlines may be needed as early as Fri
night and seem likely for Sat and Sat night with seas peaking
near 10 ft as the period ends.

LONG TERM /SUNDAY THROUGH MONDAY/...
As of 3 PM Thursday...Unfortunately for the marine community,
this period will pose treacherous wave conditions with hazardous
seas nearly a certainty as Maria approaches and passes slowly
north, but off the SC/NC coast. The slow movement north will
bring prolonged and dangerous marine conditions, as 5-8 foot
seas Sunday build to 6-11 feet early next week, remaining
elevated before a more notable subsiding trend late next week.
In addition to the large waves, N winds will likely gusts to 25
KT Sunday through early next week as Maria passing slowly north
well offshore. This will only throw another layer of hazard on
top of an existing one. The energetic, fast moving long period
energy will instigate turbulence in area inlets during the
outgoing tides, and will produce larger than normal breakers
near sand-bars while expanding the width of the surf zone. This
will require multiple days of advisories, likely initiated by
the weekend.

&&

.TIDES/COASTAL FLOODING...
As of 3 PM Thursday...High tide on the Cape Fear River downtown
will occur at 1127 PM tonight. There appears to be about a two
hour window of Advisory-worthy coastal flooding. Advisory being
issued with the afternoon package 03-05Z.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...

SC...None.
NC...Coastal Flood Advisory from 11 PM EDT until 1 AM EDT
tonight for NCZ107.
MARINE...None.

&&

$$

SYNOPSIS...MJC
NEAR TERM...MBB
SHORT TERM...III
LONG TERM...MJC
AVIATION...MBB
TIDES/COASTAL FLOODING...MBB