Area Forecast Discussion
Issued by NWS Wilmington, NC

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799
FXUS62 KILM 180226
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
1014 PM EDT Tue Apr 17 2018

.SYNOPSIS...
High pressure will move from the Gulf of Mexico to Atlantic on
Wednesday, and warm southwesterly flow will develop across the
area. A dry cold front will move across the area Thursday
night, followed by high pressure Friday and Saturday. A low
pressure system will move across the Gulf Coast states and bring
increasing chances of rain late Sunday into early next week.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
As of 1012 PM Tuesday...Low-level jet taking off now, 55 kt at
2000 feet in recent VWP returns, while on local runways, 6-9 kt
inland and 8-15 kt by the coast. GOES-E nighttime channels show
clear skies about the region, and the blustery off shore wind
flow will maintain cloudless, and fogless conditions overnight,
aside from only pieces and strands of cirrus moisture.

As of 300 PM Tuesday...High pressure across the Gulf of Mexico
will  move east and reach the Florida peninsula this eve before
moving into the Atlantic on Wed. A very weak shortwave skirting
by to our N may bring a bit more cloudiness late tonight and
into Wed, mainly across northern areas. There may also be some
clouds associated with a strengthening seabreeze boundary Wed
afternoon and eve. Otherwise, skies will be clear this period.

We will be under the influence of warm air advection this
period. 850 mb temps will continue to warm, peaking in the 12
to 16C range Wed. Lows tonight are expected to be in the upper
40s and lower 50s, with the coolest locations in the mid 40s.
Highs on Wed will be above normal, lower 80s with upper 70s
nearer to the coast. The beaches will be no higher than the mid
70s and with the prevailing SW flow, southernmost New Hanover
and coastal Brunswick counties may not get above the lower 70s.

Still a rather tight pressure gradient in place through Wed with
low pressure across the Northeast states and high pressure to
our S and winds to 40 to 50 kt at 5-6 kft. This will bring winds
at the surface to 15 to 25 mph with gusts up to 25 to 30 mph
with a few gusts above 30 mph possible. Afternoon relative
humidity Wed will be as low as 25 to 30 percent inland.

&&

.SHORT TERM /6 AM WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
As of 300 PM Tuesday...Dry period on tap with one area of high
pressure yielding its control over the region to another. Mid
level pattern remains flat, preventing any moisture return ahead
of a dry cold front expected to cross the area on Thu. Low
level warm advection will push temperatures above climo Wed
night and Thu. Westerly flow aloft helps maintain deep dry air,
precipitable water stays well below an inch on Thu, while strong
inversion based around 7k ft prevents any upward motion. Cold
advection develops in the wake of the front Thu night with temps
dropping into the upper 30s to lower 40s by Fri morning.

Main concern during the period will continue to be very dry and
windy conditions coupled with above normal temperatures. On Thu
sustained wind speeds will approach 20 kt with relative humidity
potentially dipping into the 20 percent range. Also a little worried
about nighttime humidity recovery Wed night. Currently forecast
brings humidity well into the 70% range. Would not be surprised to
see values much lower in some areas, especially given breezy
conditions expected Wed night.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
As of 300 PM Tuesday...Mid/upper level trough will shift off the
coast Friday. Broad surface high pressure over the Great Lakes
will extend across the area, resulting in cool and dry
northerly flow, which will veer to the northeast by Saturday. A
closed mid-level low and associated surface system will slowly drift
across the Gulf Coast states Sunday through Tuesday, and bring
increasing chances of rain late in the weekend and into early
next week. The GFS and ECMWF keep the bulk of the moisture and
upper-level diffluence just south of the forecast area, however
confidence is somewhat low in how this will ultimately evolve,
as there is some suggestion in the models that it may become
cutoff and slow or stall over southern Georgia or the Florida
Panhandle by Tuesday.

&&

.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
As of 00Z...Too little moisture exists for anything but high
clouds over the next 24 hours. Winds will be a concern however.
As surface winds diminish to 8-10 knots by 03-04Z, increasing
westerly winds aloft should create low level wind shear with
wind speeds at 800-1000 feet AGL reaching 30 knots, and winds at
1800-2000 feet AGL reaching 40 knots. A strong seabreeze should
develop Wednesday afternoon with surface winds at MYR/CRE
increasing to near 20 knots sustained with gusts likely over 25
knots.

Extended outlook...VFR.

&&

.MARINE...
NEAR TERM /THROUGH WEDNESDAY/...
As of 1012 PM Tuesday...Marine Weather Statement needed, to
address low water levels occurring with the overnight low tide,
no changes otherwise. Outer waters will occasionally see 25 kt
gusts overnight.

As of 300 PM Tuesday...A Small Craft Advisory is in effect
beginning  early Wed afternoon. Conditions will only be just
below Small Craft Should Exercise Caution late this afternoon
and tonight and will cap at 15 to 20 kt. The strongest winds
this period will be 20 to 25 kt later Wed afternoon. The wind
direction will be SW through the period. Seas will be 3 to 4 ft
through Wed morning, building to 4 to 5 ft Wed afternoon.

Water levels may drop below minus 1 ft MLLW and as low as near
minus  2 ft MLLW around low tide, overnight and again Wed
afternoon.

SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
As of 300 PM Tuesday...Surface high off the southeast coast Wed
night and Thu will be replaced by Canadian high Thu night
following the passage of a strong cold front. Ahead of the front
the pinched gradient Wed night will continue southwest flow 20
to 25 kt into Thu with seas running 4 to 7 ft. Front moves
offshore and across the waters later Thu with strong offshore
flow developing for Thu night. Speeds may drop under 20 kt late
Thu or Thu night but there remains potential for the SCA (which
currently runs into Thu afternoon) to be extended into Thu
eve/night. Offshore direction will knock seas from 4 to 7 ft
midday Thu to 3 to 5 ft late Thu or Thu night.

LONG TERM /FRIDAY THROUGH SUNDAY/...
As of 300 PM Tuesday...Surface high pressure will build across
the Great Lakes Friday and Saturday, and produce northeast flow
across the waters both days. The high will weaken and extend
across the DelMarVa peninsula Saturday night into Sunday, and as
a result winds will veer towards the east during that time.
Winds Friday morning will start off 15-20 kt, but diminish by
midday as the gradient weakens, and the direction may become
somewhat variable at times. It will begin to tighten up again
Sunday afternoon as low pressure slides across the Gulf Coast
states.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...Small Craft Advisory from 1 PM Wednesday to 6 PM EDT Thursday
     for AMZ250-252-254-256.

&&

$$

SYNOPSIS...CRM
NEAR TERM...RJD/MJC
SHORT TERM...III
LONG TERM...CRM
AVIATION...TRA



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