Area Forecast Discussion
Issued by NWS Wilmington, NC

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FXUS62 KILM 260801

Area Forecast Discussion
National Weather Service Wilmington NC
401 AM EDT THU MAY 26 2016

Summer-like warmth will prevail today and Friday as an upper
ridge holds across the region. An area of low pressure organizing
near the Bahamas will drift west towards the southeast United
States coast this weekend. This slow moving feature will waver in
the vicinity through early next week bringing a good chance for
showers and thunderstorms.


As of 3 AM Thursday...Movies from space on the vapor channel show
a pronounced and parched upper ridge maintaining a grip on the
eastern Carolinas, as tenuous cirrus spills southward. It does not
appear this slight veil of ice crystals will impact warm maximum
temperatures today of middle and upper 80s, but a few sundogs are
not out of the question this morning. Radar will begin sensing the
presence of sea breeze convergence around midday along the coastal
interior before lifting northward and losing identity as the
synoptic flow begins to match its vector. This alignment will
bring MAX-T `time of-occurrence` earlier in the day when compared
to deeper inland. Dryness aloft wins out, no mentionable pop
values today through tonight. Mild S-SSW winds overnight will slow
the late night temperatures drops, settling at 64-68 degrees
daybreak Friday.


As of 3 AM Thursday...Prime headline this period is arrival of
the leading edge of an elevated precipitable water surge onto the
Carolina coasts Friday night. This will set a trend of rising
dewpoints and layered absolute humidity. A continued trend of
deepening moisture through Saturday will deliver precipitable
water values near 2 inches and dewpoints around 70. By this time a
surface low will be positioned offshore somewhere between JAX and
CHS. One discernible consensus among the GFS/ECMWF/NAM solutions
is that despite exactly where...a slow drift landward toward the
NW is portrayed for Saturday into Sunday. Even given the abundant
vapor, forcing and details precludes likely or wash- out pops and
values were held in a 35-50 percent range Saturday. MAX-T Saturday
around 3-6 degrees cooler than Friday due to clouds and moisture,
but because of the elevated humidity Saturday, heat indices are
similar both days.


As of 300 AM Thursday...The forecast challenge for the extended
continues to be exclusively about a potential tropical/sub-tropical
low which will meander in the vicinity. Guidance remains in very
good agreement that a low pressure will be off the southeast coast
Saturday and then waver through the middle of next week - but any
fine details are still very far from being ironed out.

That being does appear an unsettled period is becoming
more certain...although a 3-4 day washout is not expected. The
surface low will likely track WSW Sunday as the western Atlantic
ridge holds firm...before finally...and very slowly...moving NNE
through the remainder of the period. The steering flow is
exceedingly weak until a mid-level trough digs across the northern
tier states causing the ridge to open up and allowing the system to
move northward...but that may not happen until Tue. This suggests
all 4 days will be partly cloudy with periods of heavy rainfall
and thunderstorms in an environment characterized by increasing
PWATs on deep and moist easterly flow.

Still...timing when the heaviest rainfall is likely is challenging.
Sunday may actually be the quietest day as some subsidence moves
overhead as shown on time-heights and the low stays pretty far to
the south of the ILM CWA. As it starts to lift north...especially
Mon/Tue...850mb wind u-vectors reach -3 SD`s which combined with the
approach of the low will favor increasingly heavy rainfall
chances...and will try to show at least somewhat better certainty in
rainfall then. Even so...Sun/Wed will also likely feature periods of
showers/tstms in the moist/unstable environment...but the coverage
may be less on these days. Winds will likely not be too much of a
factor regardless of whether the system acquires tropical
characteristics as the STRONGEST of the guidance keeps min SLP well
above 1000mb with a weak PG otherwise. So heavy well
as strong rip currents...will be the primary hazards in the
timeframe surrounding Memorial Day.

It is important to note that all of this is dependent on a system
that has yet to develop so changes can and will likely occur. Once
the system begins to organize the finer details will become more

Temps will be warm but likely below climo due to clouds and
rainfall...but breaks would allow for short duration heating and
will show highs just below guidance...with lows struggling to fall
much below 70 each night.


As of 06Z...High confidence in VFR through the valid TAF cycle
as high pressure remains in place. Nearly clear skies tonight
will continue through Today, with few mid to high clouds through
the morning hours. Southerly winds 4-7 kts. After daybreak, VFR
continues with southwesterly winds early becoming southerly in the
afternoon, increasing to around 10 gusts to 17 kts.

Extended Outlook...MVFR possible in scattered to numerous showers,
isolated TSTMS this weekend. Otherwise expect VFR.


As of 3 AM Thursday...Cooperative marine conditions today and
tonight as a high pressure cell off Cape Fear becomes absorbed by
a broader Bermuda anti-cyclonic circulation. This will result in
SW winds 10 kt becoming S 15 kt this afternoon, with a few higher
inshore gusts during the heart of the sea breeze middle to late
afternoon. Seas will be a composite of SE waves 2 FT every 8
seconds and a light to moderate S-SW chop. No TSTMS or VSBY
restrictions expected today through tonight.

As of 3 AM Thursday...Marine conditions will become more
challenging into the weekend as seas build due to growing wave
energy from the ESE in dominant periods of 8-9 seconds. An
advisory is not out of the question by Saturday as wave heights
approach 6 feet. Showers and isolated TSTMS can be expected
beginning Friday night and mariners should get a check on
conditions before heading out this holiday weekend, including a
look at radar trends. E winds 10 kt Friday will ramp up to NE 15
kt gusts to 20 kt Friday night into Saturday. The National
Hurricane Center is monitoring low pressure from the Bahamas for
potential development into the weekend, please stay tuned.

As of 300 AM Thursday...Marine conditions will be significantly
dependent on a low pressure system progged to move out of the
Bahamas and towards the coast this weekend. Guidance still differs
on the exact timing...placement...and strength of this
feature...but it is most likely a weak low pressure will move
across the coastal waters Sunday and Monday. Although the low
pressure will be weak...prolonged easterly fetch will build a long
period swell to 4- 7ft at 8 sec...creating seas of 3-5 ft...with 6
fters possible. Most of the contribution to the sea spectrum will
be from this winds are forecast to remain rather
light...from the E/SE at 10-15 kts...barring any unforeseen
strengthening of the low pressure.




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