000
FXUS62 KILM 211518
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
1120 AM EDT Sat Oct 21 2017

.SYNOPSIS...
Warm and dry weather is expected through the weekend, as high
pressure moves off to the northeast. A coastal front will bring
showers and a few thunderstorms late Monday and Tuesday. Cooler
temperatures will overspread the region through mid-week, as a
cold front sweeps off the coast.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 915 AM Saturday...Surface high pressure in place along the
East Coast along with ridging aloft will result in another warm and
dry day. Water vapor imagery shows moisture streaming up from the
Gulf of Mexico, however the position of the mid/upper ridge will
keep the bulk of this plume west of the forecast area through
tonight. Good insolation today will yield high temperatures around
80F most locations. Some high level moisture wilL increase overnight
and could impact low temperatures, which are expected to range a
couple categories above normal.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
As of 333 AM Saturday...The weekend will close out with plenty
sunshine, and above normal temperatures. Moisture advection
will increase Monday bringing clouds, and rain chances late
Monday as a semi-tropical coastal warm front lifts north. This
will allow for another warm day Monday in this late october,
even with increasing clouds. Rain chances will peak Monday night
into early Tuesday as moisture and over-running aloft increase
ahead of an approaching system. The moisture sources include
SFC-700 mb Atlantic and H7-H4 Gulf taps. This is shown well in
model animations of PWAT, depicting an elevated swath of
precipitable water surging through 00z-12z Tuesday. No cool air,
as the WAA pattern prevails this period, but a chance of
rainfall, with current QPF over a half inland along i-95 and
quarter inch near the coast Monday night.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 3 PM Friday...Week begins with highly amplified pattern
over the eastern CONUS. Deep 5h trough, which may or may not
become briefly cutoff, will be over the Mississippi Valley Mon
morning and steadily moving east, pushing a cold front with it.
Mid-level ridging along the Southeast will also shift east, but
the rate at which these features move ultimately determines when
showers and thunderstorms ahead of and along the front reach
the area. Strong warm advection ahead of the front will push
temps close to 10 degrees above normal Mon while ensuring
abundant moisture. Still to early to say if strong or severe
storms are a threat but low level jet Mon night and Tue will be
40-50 kt so at least some potential exists.

Front crosses the area during Tue but cold advection will be delayed
and temps will be near to slightly above climo. A shortwave dropping
southeast across the western Great Lakes and into the OH/KY Valleys
Tue night drives a cold surge into the southeast Wed. Cold advection
will drop 850 temps from low teens late Tue to near zero Wed night,
ushering in a 36 to 48 hour period of temperatures 5 to 10 degrees
below climo. Mid-level trough axis shifts off the coast Thu morning
and lifts northeast during the day. Warm advection will already be
under way at this point but cold air will linger at the surface
through Thu. Thu night or Fri will see temperatures return to levels
typical of late October in the southeast.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
As of 16Z...Cirrus is spilling over the ridge and will become broken
later today. Mainly onshore flow will become calm this evening with
continued broken cirrus. Inland terminals may see a brief period of
MVFR fog around sunrise. Sunday, continued high clouds with a
stratocu ceiling possible at the inland terminals toward the end of
the forecast period.

Extended Outlook...Showers and thunderstorms may result in flight
restrictions Mon-Tue.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
As of 915 AM Saturday...Surface high pressure stretching from the
Carolinas to the Mid-Atlantic region will maintain northeast to
easterly flow across the coastal waters through tonight. The
pressure gradient is fairly weak and winds will be around 10 kts
or less. Seas will be 3 ft or less as well.

SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
As of 333 AM Saturday...A welcoming marine environment greets
mariners Sunday, but conditions deteriorate Monday as a coastal
front ahead of an approach storm system moves north across the
0-20 NM waters. This will bring limited visibility in rain and
isolated TSTMS Monday night and early Tuesday. A small craft
advisory will likely be needed from Monday afternoon through
Tuesday, as SE-S winds gusts between 20-25 kt, and seas offshore
build to 7-8 ft overnight into Tuesday. Sunday`s sea spectrum
includes 1 ft E waves every 4-5 seconds and ESE waves 2 ft every
9 seconds. SE wave energy will begin to increase wave amplitude
Monday, primarily in 6-7 second intervals.

LONG TERM /TUESDAY THROUGH WEDNESDAY/...
As of 3 PM Friday...Cold front approaching from the west will
lead to increasing southerly flow on Mon. Winds start out east-
southeast 10 to 15 kt but turn more southerly during the day,
increasing to a solid 15 kt later in the day. Winds peak at 20
to 25 kt late Mon night and continue in the 20 to 25 kt range
into Tue evening before dropping under 20 kt Tue evening/night
and shifting to offshore as the front passes. Seas ahead of the
front will build to 5 to 7 ft Mon night and exceed 8 ft in
places on Tue. Headlines will likely be raised early Mon night
and continue through Tue and into the first part of Tue night.
Combination of offshore flow and decreased speeds late Tue night
and Wed should allow conditions to drop below headline
thresholds. Cold advection following the front is delayed so
offshore flow will not be strong right behind the front. However
cold air is expected to arrive near the end of the period and
offshore winds approach 20 kt Wed night.

&&

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

&&

$$

NEAR TERM...SRP
SHORT TERM...MJC
LONG TERM...III
AVIATION...43

NWS ILM Office Area Forecast Discussion