Area Forecast Discussion
Issued by NWS Wilmington, NC-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
FXUS62 KILM 311507
Area Forecast Discussion
National Weather Service Wilmington NC
1100 AM EDT WED AUG 31 2016
Unsettled conditions can be expected the next couple of days. By
Friday a tropical system will move just offshore bringing with it
strong winds and heavy rainfall. High pressure builds in for the
Labor Day weekend with pleasant conditions which will continue
well into next week.
.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --As of 1100 AM Wednesday...Interesting change in the 12z WRF in that
it now shows upper low to our south strengthening rather
thanweakening as it lifts northward across the area today. This may
bodewell for precip chances even as the surface reflection near
JAXshows little movement. The seemingly well-initialized HRRR on
theother than not so impressed with much falling over much of NC.
Willgo ahead and increase POPS over mainly coastal NC but later
thisevening, much more in line with SREF output as there seems
notingenvironmental at this time to preclude the upper low`s ability
tospread rain northward as it lifts.
It will be another warm and humid day with highs inland near 90 or
in the lower 90s. As you near the coast, onshore flow and a greater
coverage of clouds and showers should keep highs in the upper 80s
with mid 80s at the beaches. Lows tonight will again be in the lower
to mid 70s.
-- End Changed Discussion --
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
As of 315 AM Wednesday...We will be closely monitoring the
strength and track of a tropical cyclone this period. Latest
information from the National Hurricane Center has a tropical
cyclone tracking up the southeast coast. A strong cold front is
still expected to move southeast and across the area Thu night and
Fri morning. At the same time, the tropical cyclone will be
accelerating to the NE ahead of the trough. The front will likely
stall just offshore until the cyclone moves by, locking in a
tropical environment. Once the tropical cyclone does move off to
the NE, much drier and cooler air will be ushered in across the
Carolinas, perhaps as early as late Fri night and Sat.
Impacts across the forecast area and timing are not nailed down
quite yet. However, certainly a much wetter picture is beginning to
be painted as isentropic lift and a tropical system sync up. Our
current best estimate is for 5 to 7 inches along the more immediate
coastal areas and then 3 to 5 inches a little further inland with 1
to 3 inches for areas generally west of EYF, MAO to near CKI. A
Flood Watch may be required for portions of the area if the current
QPF projections hold.
Also, with the new moon on Fri, and a strong onshore push, we may
have to contend with coastal flooding for the immediate coast and
along portions of the lower Cape Fear River during high tide. Other
impacts will include beach erosion, strong rip currents and high and
very rough surf. Storm surge is also possible, but the exact path of
the storm will be crucial as to the magnitude of any surge.
Finally, there is the wind to contend with and certainly the
intensity of this system will largely determine that although
proximity to land and overall geographic size will also be
significant factors. Tropical storm force winds are certainly
possible with a higher probability along the more immediate coast
than areas well inland. The strongest winds should occur over the
waters. The National Hurricane Center will continue to monitor with
NOAA aircraft routinely investigating the storm. Tropical headlines
will be issued as confidence in the track and timing increases,
perhaps as early as later today or tonight for portions of the
.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 315 AM Wednesday...The mid level pattern will transition
to one of modest ridging with the center in the southeast with
somewhat deep troughing out west. At the surface it will be
massive high pressure building in from north and moving little as
the parent pattern moves slowly. There is only one hint of pops
through the period with a surge front Saturday but even this seems
a stretch. The latest MEX guidance remains consistent with highs
in the lower to mid 80s and overnight lows in the 60s. Still no
50s in the guidance but close in LBT with 62.
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
As of 12Z...LIFR affecting LBT at this time. Conditions may bleed
into ILM, but have left that scenario out at the moment. Upper low
will try to drag moisture northward. Confidence fairly high that
convection will reach the Myrtles at the minimum by early
afternoon, possibly affecting ILM a couple of hours later. Brief
IFR conditions are possible. Light gradient will allow an onshore
flow later today.
EXTENDED OUTLOOK...Tropical storm conditions are possible from late
Thursday night through Friday night.
-- Changed Discussion --NEAR TERM /THROUGH TONIGHT/... As of 11 AM Wednesday...No changes as
usual with such light winds inplace. Gaston swell still abating and
no headlines. The gradient isso weak today due to a lineup of
troughiness from TD 8 to the lowjust east of JAX, all displacing the
west atlantic high further outto sea. Previous discussion follows.
As of 600 AM Wednesday...Showers and some thunderstorms were
increasing across the southernmost waters and moving N.
Winds and seas will be rather benign this period. Swell from
Gaston will be the primary driver of seas, up to 3 to 4 ft. Winds
will be up to 15 kt, strongest this afternoon and eve. An easterly
wind direction will dominate with winds backing to northerly later
tonight as trough/weak low pressure moves off.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
As of 315 AM Wednesday...Much more dangerous marine conditions
are expected to develop across the waters with the worst of the
conditions likely to develop from S to N beginning late THU night
and FRi and then beginning to gradually improve, again from S to
N, Fri night. The timing and specifics hinge on a cold front
reaching the area Fri morning as a tropical cyclone accelerates to
the NE along and ahead of this strong front.
Tropical storm force winds are currently in the forecast, but wind
speeds will be adjusted in later forecasts and will be highly
dependent on the exact track and intensity of the tropical cyclone
as it reaches our latitude. It is not impossible that winds and seas
could be higher than currently forecast. Mariners should continue to
closely monitor later forecasts. Tropical headlines will be issued as
needed with later forecasts.
LONG TERM /SATURDAY THROUGH SUNDAY/...
As of 315 AM Wednesday...A few hours of strong northerly winds
will continue across the waters Saturday morning as a tropical
system pulls away quickly to the northeast. By Saturday evening
wind speeds will be down to ten knots or less from northeast. As
high pressure builds in Sunday speeds will increase a touch to
10-15 knots. Significant seas will follow a similar trajectory
with a healthy 4-7 feet early Saturday to 3-5 feet later Sunday.
-- End Changed Discussion --
SC...High Rip Current Risk through this evening for SCZ054-056.
NC...High Rip Current Risk through this evening for NCZ106-108-110.