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606
FXUS62 KILM 182330
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
730 PM EDT Wed Apr 18 2018

.SYNOPSIS...
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High pressure will move offshore tonight. A strong cold front
arrives late tomorrow. High pressure will pass by well north of the
area over the weekend. A slow moving area of low pressure will
approach from the west and move overhead through the early and
middle part of next week.
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&&

.NEAR TERM /THROUGH THURSDAY/...
As of 618 PM Wednesday...No changes to ongoing forecast aside
from loading the latest observations into the gridded forecast
database for good initialization heading into the evening hours.
Temperatures will drop into the 60s after dusk, then level off
not long after midnight, in the low 60s inland and middle 60s
near the coast, where breezes will be stronger and low-lvls more
mixed. Inshore SSTs and surf temperatures have slowly risen to
around 65 degrees. Dewpoints will rise into early Thursday and
a higher humidity feel may be observed just ahead of a front.
The recent GOES-E imagery shows a high probability of clear
skies overnight, at most, bits and pieces of ice crystal clouds
caught in rapid zonal wind flow, not impactful on forecast
hourly temperature curves.

As of 3 PM Wednesday...Surface high will linger off the coast
into Thu before a strong cold front moves across the area during
the day. Ahead of the front gusty winds and very dry conditions
will once again lead to an increased fire danger risk. West-
southwest winds of 15 to 20 mph are expected with gusts around
30 mph possible. Cold advection spreads over the area from west
to east during the afternoon and will complicate high temp
forecast somewhat. Highs will range from lower 80s closer to the
coast with mid to upper 70s inland. Front passes dry, although
it is likely to be accompanied by some flatter cumulus. Forecast
soundings show an increase in moisture between 4k and 5k ft but
the cap above 6k ft or so will prevent any deep upward motion.
Band of increased moisture is narrow and by late afternoon any
cloud should be off the coast with cold advection underway
everywhere. Advection continues overnight with northwest winds
gradually becoming north late in the period. Despite winds over
10 mph temperatures will drop into the upper 30s to lower 40s as
the period ends.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 3 PM Wednesday...Dry cold front will be off the coast as the
period begins with surface high building in from the northwest.
Strong cold advection sets up Thu night with temperatures dropping
into the upper 30s to lower 40s for Fri morning. Mid-level trough is
slow to move away from the east coast Fri. This keeps deep northwest
flow and post trough subsidence over the forecast area through Fri
night. Forecast soundings do show increasing moisture above 25k ft
late in the period and some cirrus may spread over the region Fri
night. Other than the late period high cloud skies should remain
clear with no chance of rain. Precipitable water will stay under
half an inch, sometimes dropping below a quarter inch, through the
period. Temperatures below climo continue Fri and Fri night. Highs
Fri may struggle to hit mid 60s despite an abundance of sunshine.
Northerly winds ease up Fri night which could lead to strong
radiational cooling. So despite airmass modification, lows Fri night
will be similar to Thu night lows, and possibly cooler.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 300 PM Wednesday...Temperatures will remain below climatology
through  the period while the weather becomes increasingly
unsettled. The Saturday through Sunday should be rain-free as high
pressure is passing by to our north. As this happens a cutoff upper
low will move across the Gulf states leading to cyclogenesis. Clouds
and perhaps rain will then overspread the region Sunday night. With
the high holding on to our north there will be a good overrunning
surface with warm advection over the top. This will favor an
appreciable QPF event, especially paired with the overall slow
motion of the system; so much so that rain may last into Wednesday.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
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As of 00Z...Expect gusty SW winds to diminish a little and lose
their gusty character after sunset under mainly clear skies.  Strong
low level winds will remain in the lower 2 Kft though so have
included low level wind shear at all sites through 12 to 14Z.  Winds
will increase after sunrise running 10 to 15 KT with gusts over 20
KT possible as the day progresses.  By the end of the TAF period,
winds will become W to NW.  VFR conditions are expected through the
valid TAF period.

Extended outlook...VFR through Sunday.  MVFR is possible at time
Monday with rain in the area.
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&&

.MARINE...
NEAR TERM /THROUGH THURSDAY/...
As of 618 PM Wednesday...An Marine Weather Statement was needed
to address the low water levels with the overnight low tide,
dipping to 1-2 ft below the `normal` low tide. No other changes,
SCA flags are flapping in stiff SW marine breezes, and pitchy,
unwelcoming seas offshore.

As of 3 PM Wednesday...Strong southwest flow this afternoon will
continue overnight and Thu, prior to the passage of a strong cold
front in the afternoon. Ahead of the front speeds will be 20 to 25
kt with potential for gusts around 30 kt. Once the front passes
winds shift to offshore and decrease in speed somewhat. Currently
the SCA headline expires at 21Z and have no plans to change the end
time. Cannot rule out changes down the road and would not be shocked
to see the headline extended out in time, just do not have high
enough confidence at this time. Seas will build to 4 to 7 ft this
evening and stay there into Thu afternoon before offshore flow
knocks seas to 3 to 5 ft late in the day.


SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...

As of 3 PM Wednesday...High pressure to the northwest will build
over the waters as Thu cold front moves farther away from the coast.
Gradient remains pinched as the high builds in Thu night with 15 to
20 kt northwest winds gradually becoming north-northeast early Fri.
Current SCA headline expires before the start of the short term
period, but there is a chance the headline will need to be extended
into Thu night to account for the northeast surge. Gradient relaxes
Fri into Fri night as the high slowly drifts southeast. Northerly
flow continues through the period but with speeds 10 kt or less from
Fri afternoon on. Seas running 3 to 5 ft Thu night will slowly
subside later Fri and Fri night, ending up around 2 ft.

LONG TERM /SATURDAY THROUGH MONDAY/...

As of 300 PM Monday...Large area of high pressure passing by to our
north over the weekend. Initially this will bring fairly light NE
winds but as the high moves farther east and an area of low pressure
approaches the flow will turn easterly and wind will accelerate.
Conditions should deteriorate to Advisory levels Sunday night.
Additionally some fairly heavy rain will lead to considerable
visibility restrictions adding to the hazard level of the marine
environment.

&&

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

&&

$$

SYNOPSIS...MBB
NEAR TERM...III/MJC
SHORT TERM...III
LONG TERM...MBB
AVIATION...RAN