Area Forecast Discussion
Issued by NWS Wilmington, NC

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FXUS62 KILM 182037
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
337 PM EST Tue Dec 18 2018

.SYNOPSIS...
High pressure over the Carolinas tonight slides offshore
Wednesday. Low pressure developing over the Deep South will
bring another significant rainfall event Thursday and Thursday
night. Dry high pressure and seasonably chilly temperatures are
expected for the weekend.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
As of 3 PM Tuesday...Shortwave energy ejecting out of TX upper low
will cross the region late tomorrow. It`s approach will develop a
surface trough offshore while warm advection leads to isentropic
upglide. Models are not in agreement as to whether this merely leads
to cloudiness or actually brings some rain. Have opted to introduce
some low chance POPs in deference to the aggressive WRF solution but
the uncertainty and drier guidance makes capping QPF at just 1-3
hundredths appropriate. Before the clouds increase tonight there
should be ample time with light winds and minimal cloud cover for
lows to radiate down into the lower 30s. Highs tomorrow will be
seasonably cool.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
As of 3 PM Tuesday...Short term period will be characterized by
a return to wet wx and potentially heavy rainfall. For Wednesday
night, a coastal trough will lead to scattered showers over
coastal areas, before the better chances of rain arrive area-
wide into Thursday morning as warm air advection and moisture
transport increase out ahead of a digging upr-level trough. The
rain will be moderate to heavy at times into Thursday aftn, as
several spokes of energy rotate around the upr-level trough. The
rain continues into Thursday night, with the heaviest expected
over NC by then. Some light QPF expected Friday, although it`s
not expected to rain the entire day. Storm total QPF is mainly
1-2 inches, with isolated areas of 3 inches possible, especially
near the NC coast. Main instability should remain offshore, so
not expecting thunderstorms to be an issue through the period.
High temperatures will be in the 60s Thursday and Friday, which
is between 5 and 10 degrees above normal for December.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
As of 3 PM Tuesday...Dry wx returns for the entire long term
period with surface high pressure over the area. With zonal flow
aloft and W low-level flow (instead of NW) behind the
de-amplifying upr-level trough, not much cold air advection
expected over the weekend. Thus, temps will be close to
climatological norms Saturday and Sunday...highs in the mid/upr
50s. Similar temps into next Monday and Tuesday under
mostly/partly sunny skies.

&&

.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
As of 18Z...High pressure will stay in control through most of the
forecast period. No aviation concerns through the overnight hours
with only cirrus expected. Wednesday, a weak  coastal trough tries
to set up with possible scattered/isolated showers along the coast.
A VFR stratocu ceiling is expected with mainly a light east
northeast wind.

Extended Outlook...Unsettled weather Wednesday night through Friday
with a fairly strong system setting up. Potential for occasional
heavy showers Thursday through Friday morning. Expect brief IFR
conditions and windy in convection, particularly Thursday night.

&&

.MARINE...
NEAR TERM /THROUGH WEDNESDAY/...
As of 3 PM Tuesday...NE flow will veer gradually with the
formation of a coastal trough through the period. Wind and
waves will tend to run 10-15kt but may fall to 10kt as the
trough develops and the gradient pinch moves inland. Seas will
fall to 2 ft and tend to remain.

SHORT TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
As of 3 PM Tuesday...Next round of Small Craft Advisory
conditions commences Thursday aftn ahead of surface low pressure
developing over the SE states. Winds and seas continue to ramp
up into Thursday night...seas up to 6-9 kt and southerly winds
of 15-25 kt. Strongest winds are expected late Friday, with
occasional gusts to gale force possible. Marine conditions then
slowly improve into Saturday as high pressure builds in from the
west.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...None.

&&

$$
SYNOPSIS...MAS
NEAR TERM...MBB
SHORT TERM...MAS
LONG TERM...MAS
AVIATION...MBB
MARINE...MAS/MBB


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