Area Forecast Discussion
Issued by NWS Wilmington, NC-- Highlight Changed Discussion --
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FXUS62 KILM 300244
Area Forecast Discussion
National Weather Service Wilmington NC
944 PM EST Tue Nov 29 2016
Mild, southerly breezes will continue tonight and Wednesday as
a cold front approaches the Carolinas from the west. This front
will move offshore early Thursday morning. Canadian high pressure
will bring cool, dry weather Thursday through Saturday. Several
areas of low pressure developing along a front will bring clouds
and increasing rain chances early next week.
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
-- Changed Discussion --As of 815 pm Tuesday...As the showers tracked east past the I-95
corridor, their areal coverage decreased along with their
intensity. With this activity well away from the strong
mid-level dynamics, expect this continued slow diffusion of the
pcpn to continue overnight. Eventually, pops decrease to slight
chance overnight and will hold onto that threat across the
inland Carolinas. However, along the immediate coast, with wind
just off the ground running 30 to 40 kt, showers may move
onshore and/or parallel to the Carolina coastlines overnight
due to frictional or speed coverage from those stronger winds
moving onshore. Surface winds overnight will remain quite active
keeping temps elevated, mainly in the mid to upper 60s. Even
the immediate coast will remain in the 60s this due to ssts
across the adjacent Atlantic inshore waters now into the mid to
upper 60s with low 70s shown by local buoys just offshore...ie.
41037 and 41064. Local sfc dewpoints will also remain in the 60s
with the atm having become quite moist with PWs in the 1.25 to
1.60 inch range.
As of 300 PM Tuesday...Temperatures are now well up in the 70s
most everywhere except a bit lower at some beach locations.
Isolated to widely scattered pre- frontal light showers continue
area- wide with the forecast area firmly located in the warm
sector of a slowly approaching frontal system. Guidance shows
the slight to low chance of this activity continuing overnight
with a focus on our inland counties. QPF will be minimal
overall, with most places seeing well under a tenth of an inch.
Strong WAA in advance of the front will continue to prop up
temperatures through the overnight period, with lows remaining
elevated in the mid 60s.
Gusty winds will continue through the afternoon hours with peak
gusts up around 30 mph not uncommon. VAD wind profiles show
impressive winds not far off the deck, generally 40 kts within 2
kft. Winds will moderate after sunset.
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.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
As of 3 PM Tuesday...The chance for convection, possibly strong
to severe, continues through Wednesday in advance of a cold
front. The best chances for precip and strong convection run
from Wednesday afternoon through the evening hours, immediately
preceding the front. Rain chances end from west to east as the
front moves offshore Thursday morning. Thursday temperatures
will be significantly cooler than Wednesday as a moderate CAA
regime sets up post-FROPA.
.LONG TERM /FRIDAY THROUGH TUESDAY/...
As of 3 AM Tuesday...Models are in good agreement that Friday
and Saturday will feature dry weather as Canadian high pressure
builds eastward into the Carolinas. The airmass should be on the
chilly side with daytime highs several degrees below normal both
days. The subtropical jet will become quite active late this
week, spreading a veil of cirrus overhead for Friday night and
I wish I could just stop the forecast with Saturday, because
model consensus goes out the window for early next week. Major
timing differences develop between the slower 00z ECMWF and the
faster 12z GFS with a shortwave trough ejecting out of the
desert Southwest and across the southern United States. While it
appears a good portion of any early precipitation will remain
light Sunday into Sunday night, varying positions of a warm
front and subsequent low pressure development along the East
Coast paint a confusing picture of what sensible weather might
develop Monday through Tuesday.
In the absence of an obvious initialization error to guide me
to one model over another, I have generally followed WPC
national guidance with respect to temperatures and
precipitation Sunday through Tuesday. This keeps at least a
chance of rain in the forecast each day, with temperatures on
the cooler side of a GFS/ECMWF blend.
Despite the ECMWF`s success record, WPC notes that the GFS 00z
and 06z ensemble members are almost universally slower than the
ECWMF with the movement of the upper system. This gives at
least some confidence that the GFS solution has some validity
in this case.
.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
As of 00Z..Isolated showers and the potential for MVFR/IFR due to
areas of fog and low cigs tonight into early Wednesday morning.
Otherwise expect VFR with increasing chances for showers and
isolated thunderstorms on Wednesday.
Latest radar imagery depicts light showers moving across portions of
the forecast area. Anticipate this activity to remain VCSH tonight
with southerly winds around 10 kts and intermittent higher gusts
possible. Latest fcst soundings continue to suggest increasing
chances for fog and low cigs overnight. As a result, anticipate
conditions to deteriorate to MVFR/IFR. On Wednesday, expect VFR with
increasing chances for showers and isolated thunderstorms. Southerly
winds will increase to around 15 kts with higher gusts possible.
Extended outlook...Potential for MVFR/IFR in showers/isolated
thunderstorms late Wednesday thru Thursday morning. Otherwise expect
-- Changed Discussion --NEAR TERM /THROUGH TONIGHT/...
As of 830 PM Tuesday...Strong SCA conditions late this aftn
will drop to weak SCA conditions temporarily overnight due to a
slight loosening of the sfc pg. In fact, wind speeds may
temporarily drop to around 15g20+ kt which is below SCA
thresholds. The significant seas will only show a slight
subsiding trend, but remain within SCA thresholds. Expect the
re-tightening to occur heading toward Wednesday sunrise and
continuing in the time there-after. Basically looking at S to
SSW winds re-increasing to 15 to 25 kt late this period.
With the onshore wind direction, the warmer ssts just offshore
have been getting pushed into the ILM coastal or local waters.
As a result, the 30 to 40 kt winds progged just off the deck,
will be able to occasionally mix down to the ocean
sfc...resulting in potential gale force wind gusts mainly
during Wed into Wed night. The increased SSTS will prevent any
sea fog issues.
As of 300 PM Tuesday...Small Craft Advisory will continue
through the near term. There is the likelihood that conditions
could improve overnight in places such that Small Craft Advisory
criteria are no longer met. However, as conditions are likely
to deteriorate again on Wednesday, have opted to keep the
Advisory in place through the period. The latest obs show seas
in the 5 to 8 ft range over the coastal waters, with southerly
winds of 20 to 25 kts and occasional gusts to 35 kts. Latest
guidance shows a temporary loosening of the gradient overnight,
which will account for the period of slightly more favorable
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
As of 300 PM Tuesday...The Small craft Advisory is expected to
continue through late Wednesday night, when the close proximity
of a cold front will loosen the gradient enough to allow
conditions to improve by daybreak on Thursday. The front will
move across the waters early on Thursday, with gradual
improvement through the remainder of the period.
LONG TERM /FRIDAY THROUGH SATURDAY/...
As of 300 pM Tuesday...Canadian high pressure will build into
the Carolinas from the west Friday and Saturday, finally
reaching the area late Saturday night. Although major model
differences develop next week, through Friday and Saturday the
models are in good agreement with gradually diminishing offshore
winds and dry weather.
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MARINE...Small Craft Advisory until 6 AM EST Thursday for AMZ250-252-