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Area forecast discussion
National Weather Service Wilmington NC
1124 am EDT Wed Apr 26 2017

high pressure offshore will bring a warming and drying trend
into the weekend. A weakening and lingering cold front will
bring a chance of showers or a thunderstorm late Thursday and
Friday, with temperatures remaining warm. A stronger frontal
system will bring a chance of rain early next week. Inland
areas may see temperatures of 90 degrees or higher Friday
and Saturday afternoon.


Near term /through tonight/...
as of 1124 am Wednesday...W-WNW winds are pushing a stubborn
patch of strato-cumulus 7000 feet off the ground over southeast NC
toward the ocean. As these clouds become less stratified and
sail to sea, developing diurnal cumulus should pop up at around
5000 feet across the land forecast area, although with little
vertical extend as a short-wave upper ridge presses dry air
downward on their tops. The snap-back thickness values within
with the upper ridge will also boost afternoon maximums into the
80s away from the coast this afternoon. This will fuel a sea
breeze circulation bringing a bit of gustiness at the beaches
and a slight backing in wind direction there. Transition to a
synoptic return flow will commence later this afternoon and a
low-level jet overnight from the SW, bringing 25 knots winds as low
as 500 feet off the surface, will likely inhibit fog and mist
formation overnight despite damp grounds and clear skies. This
will also result in a mild night in the 60s, and winds near the
coast will support minimums elevated into the upper 60s at the
beaches as SSTs hold in a 69-72 degree range. The dry air aloft
will prevent precipiation through tonight.


Short term /Thursday through Friday night/...
as of 330 am Wednesday...low amplitude ridging aloft to affect
the forecast area Thu, complements to the northeast moving upper closed
low. The associated ridge axis, overhead at the start of this
period, will slide east and off the Carolina coasts by Thu
evening. An expansive and rather amplified upper trof will
become established across much of the Continental U.S. With it's trof axis
nearly mimicking the Continental Divide. At the sfc, weak high
pressure centered well offshore from Florida, will ridge back
across the southern portions of the forecast area Thu. An eastward moving
and weak frontal boundary, well displaced from it's parent sfc
low near Hudson Bay, will approach from the west before
stalling across the far western Carolinas and Virginia Friday
morning. Moisture accompanying the front remains limited, and
will eventually push well ahead of the stalled front by Friday
morning. Just enough dynamics and weak instability to aid
isolated to widely scattered showers late Thu night thru midday
Friday along with a possible rumble of thunder.

Upper level ridging will Spring back up across the southeast
states and the Atlantic waters. 500 mb heights rise to 590+ dam.
Strengthening Bermuda high pressure will ridge back to the west
and extend inland in the vicinity of Cape Romain by daybreak
Sat. Subsidence aloft, ie. Nva, will become more dominant late
Fri aftn and night, essentially putting a lid on any convection
that tries to develop.

The pre-dawn hours of Thu, and Fri and Sat will each feature a
SW low level jet. The stronger jets will occur Fri and Sat
mornings. This will aid in keeping SW winds active at the sfc
and in turn likely preventing any radiational fog development
each night.

As for daily Max and min temps for the 2 days, you may be
looking at the warmest temps of the Spring season so far. Model
MOS guidance shows widespread 80s both days with 90 degree
readings possible inland locations on Fri. In essence, will be
looking at Max/min temps running up to 15 degrees above climo.


Long term /Saturday through Tuesday/...
as of 300 PM Tuesday...surface and mid level ridging will be
the dominant features through the weekend. The 5h ridge axis is
just offshore and a slow but steady increase in moisture as flow
aloft becomes more southwesterly opens up the possibility of
sea breeze/diurnal convection, especially Sun afternoon and
evening. Temperatures will be above to well above climo with
potential for 90 degree readings inland.

Next system winds up over the central Continental U.S. Early next week, lifting
from the plains on sun to the Great Lakes on Mon. Warm advection
ahead of the front will maintain temps above climo through Mon. Cold
front trailing the low moves into the area later Mon preceded by
convection. Best dynamics pass well north of the area but there will
be a narrow band of deeper moisture along with low level convergence
and a strengthening low level jet. Also potential for some positive vorticity advection
depending on timing of any shortwave rotating around the base of the
trough. Surface high and broad troughing aloft Tue contribute to
deep westerly flow, drying the region out but with a cooler air mass
building in temps will be slightly below climo as the period


Aviation /15z Wednesday through Sunday/...
as of 12z...MVFR and pockets of IFR will occur across the region
thru 14z, either from ceilings 1k-2k feet and/or br/fog
especially areas outside the veil of SC/ac cloudiness. As the
stacked low moves further away today, temporary upper level
ridging and sfc ridging from off the southeast Atlantic will both
affect the forecast area by this aftn thru tonight, ending the cyclonic
flow associated with the retreating stacked low off to the
northeast. Light northwest-west flow this morning will back to the SW this
aftn thru tonight. Coastal terminals may see it back to the S
due to a the development of an aftn/evening weak sea breeze.
A low level SW 20 to 30 kt jet will develop and affect the
area terminals between 04z thru 12z Thu. This will keep winds
active at the sfc and likely prevent any widespread fog. If this
jet is weaker than expected or does not quite develop as
expected, fog would then become an issue especially with grounds
still remaining nearly saturated from the heavy rainfall event
of the past 2 days.

Extended outlook...VFR expected from Thursday afternoon through
Sunday. Isolated MVFR from spotty showers Thu night.


near term /through tonight/...
as of 1124 am Wednesday...light winds much of the day will
allow southeast swell to remain the dominant wave energy although its
intensity will wane today. By late day and overnight, increasing
SW winds will bring moderate choppiness to the waters with 4-5
second wave periods becoming more dominant along with a little
inshore gustiness this afternoon with the sea breeze winds. No
showers or thunderstorms however are expected through the overnight
period. Increasing synoptic winds may approach cautionary levels
tonight as the pressure gradient tightens and a low level jet

As of 330 am Wednesday...the system moving into the northeast
will no longer be the main wind-making feature today. In its
wake the high over the Atlantic will bring a S to SW flow. An
approaching cold front will also slightly contribute. With the
coast between the two winds will be quite light. Seas will
setting into a general 2 to 3 or 4 ft range. Some larger waves
outside of 20nm have swell energy from the departing storm as
evidenced by the 10 sec dominant period.

Short term /Thursday through Friday night/...
as of 330 am Wednesday...Thursday will feature weak ridging from
offshore high pressure east of Florida, extending inland just
south of the area waters. Thursday will see south-southwest to SW flow at
10 to 15 kt with an 8 to 9 second period east-southeast ground swell
dominating the significant seas. By late Friday thru Friday
night, strengthening ridging sfc and aloft, will affect the area
waters. The sfc pg will tighten-some, resulting with SW 10 to 20
kt winds. An east-southeast ground swell will remain present but increasing
short period wind waves will eventually dominate the significant
seas. In addition, a SW low level jet will affect the local
waters during the pre-dawn hrs of Thu, Fri and Sat. The
strongest low level jet will occur Fri morning and may just be
strong enough to produce scec and/or Small Craft Advisory conditions. Will
monitor. The aftn/evening sea breeze each day will also provide
additional choppiness to the overall seas.

Long term /Saturday through Sunday/...
as of 300 PM Tuesday...high pressure will be the dominant
feature through the period with south to southwest flow in
place. Speeds will be on the low end of the 10 to 15 kt range
early in the period but increase to a solid 15 kt sun as
gradient becomes a little more defined. Seas mostly 2 to 3 ft
early in the period will experience an upward trend late in
response to increasing southwest flow.


Ilm watches/warnings/advisories...



Near term...8

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