Area Forecast Discussion
Issued by NWS Newport/Morehead, NC
FXUS62 KMHX 271056
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
656 AM EDT SAT AUG 27 2016
High pressure will extend over the area from the north and
northeast through most of the weekend. A weak cold front will
approach form the north today, then stall and dissipate tonight
and Sunday. A weak low will approach from the southeast Monday. A
cold front is forecast to push through the area Thursday.
.NEAR TERM /THROUGH TONIGHT/...
As of 655 AM Saturday...A strong and persistent upper level high
will continue over the area through Sunday. At the surface a very
weak boundary/wind shift is forecast to drift south into Eastern
NC today after 12Z and dissipate tonight into Sunday. The low
level flow is forecast to become light NE/E this afternoon and
help to moisten the low levels. 850 MB dewpoints were already in
the mid teens Celsius on the 00Z MHX sounding and surface
dewpoints will be well in the 70s with PW values around 2".
Diurnal heating will lead to destabilization of this moist airmass
resulting in a chance for showers and thunderstorms. However, any
convection will have to overcome very dry mid level air as seen in
the water vapor imagery along with high surface pressures and only
weak low level convergence. Thus will limit PoPs to 20% (slight
chance). Expecting strong heating especially through early
afternoon so will trend forecast highs toward the warmer guidance
with readings in the upper 80s coast to lower 90s inland.
.SHORT TERM / SUNDAY THROUGH 6 AM SUNDAY/...
As of 335 AM Saturday...Low level easterly flow will continue
across the area tonight. Initially there will be a very low risk
of an inland shower or thunderstorm in the early evening then any
small shower risk will shift to the coast late at night. The
guidance is suggesting that low clouds and perhaps fog will move
into the area from the northeast late. Overnight lows will range
from around 70 degrees inland to the mid 70s coast.
.LONG TERM /SUNDAY THROUGH FRIDAY/...
As of 315 AM Sat...A complicated forecast continues for the long
term period due to differences on movement and extent of tropical
activity to the south. Temperatures will generally be near to
slightly above normal through the period. A front will push
through late week with a cooler and drier airmass building into
Sunday through Sunday night...The upper ridge that has been
persistent across the Southeast will begin to weaken Sunday as a
shortwave trough pushes across the northern Mid-Atlantic and New
England states. Meanwhile, the attendant cold front gradually
dissipates across the region while a weak low retrogrades off the
Atlantic Ocean waters toward the region. With sufficient moisture,
PW`s approaching 2 inches, decent instability, LI`s around -4 to
-7C, scattered showers and thunderstorms will be possible,
potentially bringing locally heavy rainfall. Highs in the mid to
upper 80s. Precip should taper off with loss of heating, with best
chances shifting towards the coast as weak low approaches from the
Monday through Tuesday...Complications arise early next week as
the med/long range global model suite still struggling with
potential development and movement of the tropical system to the
south. Though differences remain, 00z guidance continues to show
weak low moving towards the NC coast, with secondary low moving
into the Gulf of Mexico. This solution would depict better precip
chances across the area with tropical moisture streaming into the
area. Though due to the continued uncertainty, will continue
chance pops, highest southern and eastern zones. Max temps will be
held down into the mid/upr 80s due to the cloud cover and precip,
with nighttime temps warm and muggy with lows in the 70s.
Wednesday through Friday...Some model disagreement continues
through this period as well. A long wave trough is fcst to deepen
across the eastern half of the CONUS mid to late next week and
will determine eventual fate of the tropical system. Both the GFS
and ECM bring the system back out over the Atlantic and moving off
the SE coast. ECM is a little deeper with the trough and shunts
the system out of the area Thursday, while the GFS is flatter with
the trough and therefore much slower and further offshore. Will
continue low chance pops this period due to the low confidence
forecast this far out. Models do push a front through the area
Thursday, with high pressure building in north of the area
Thursday night into Friday. Drier and cooler airmass will build in
Friday into the weekend.
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
Short Term /Through Tonight/...
As of 655 AM Saturday...High confidence in VFR conditions
persisting through this evening outside isolated
showers/thunderstorms this afternoon which could produce brief sub
VFR conditions as high pressure continues over the area.
A scattered stratocumulus cloud deck around 4-5K FT is expected
to develop today. Looks like a better chance for widespread sub
VFR (IFR) conditions in fog and stratus late tonight in Easterly
low level flow.
Long Term /Sunday through Wednesday/...
As of 315 AM Sat...Scattered to potentially numerous
showers/storms expected through the period. This may be
exacerbated by tropical moisture streaming into the area and
potentially limit cigs to sub MVFR as indicated by model
soundings. Areas of fog and stratus will be possible each
night/early morning with moist low levels and light winds.
Short Term /through Tonight/...
As of 655 AM Saturday...A weak boundary/wind shift will drift
south into the waters today and dissipate tonight as high pressure
vicinity of New England ridges south into the area. This will
cause winds to become East to Northeast this afternoon and tonight.
Speeds are expected to remain 10 KT or less through tonight with 2
to 3 FT seas. The NWPS wave model is indicating some 4 FT seas
over the outer southern and central waters today and tonight
perhaps due to a longer onshore fetch or emanating from a weak area
of disturbed weather south of Bermuda which is forecast to
retrograde toward the Southeast coast early next week.
Long Term /Sunday through Wednesday/...
As of 315 AM Sat...A weak frontal boundary will dissipate across
the region Sunday while high pressure builds back in from the
north with a coastal trough retrograding into the waters early
next week. Predominant winds through Sunday night will be
easterly 5-15 kts with seas 2-4 feet. A weak area of low pressure
will approach from the SE Sunday night and Monday...and depending
on the strength of the low could see winds increase to 15-20 knot
Monday. Otherwise E/NE winds 5-15 knots continue into Tue,
becoming SE/S Wed. Seas on the coastal waters will average 2-4
feet through Sunday. Long period swell of 13-15 seconds forecast
to impact all coastal waters beginning Sunday night as swell
energy from very distant Tropical Cyclone Gaston starts to arrive.
Seas expected to build to 3-5 feet, though could see the outer
central waters build to 6 feet through Tuesday with a period of
SCA conditions possible.