Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Newport/Morehead City NC
740 PM EDT sun Aug 28 2016
high pressure will extend over the area from the north and
northeast through tonight. A tropical depression will approach
from the southeast Monday through midweek. A cold front is
forecast to push through the area Thursday followed by high
pressure from the north Friday and Saturday.
Near term /tonight/...
as of 700 PM Sunday...updated slightly higher pops northern
sections until 8 PM, then reduced pops to 30% all zones with
wording of scattered showers and slight chc tstms. Minor
adjustments to hourly temps and dew points based on latest
obs/trends. Broken coverage of showers/sct tstms from north of hse
to near pgv is showing waning trend past hour and latest meso
models support activity diminishing next few hours, but additional
activity moving in from offshore supports continued 30% pop rest
of evening. Temps have already dropped into mid 70s with precip
but cloud cover keeping min temps in low to mid 70s overnight.
as of 400 PM Sunday...a retrograding compact upper low/trof and
tropical depression off the NC/SC coast will continue to move
towards the area as surface high pressure continues to extend over
the area from northeast through the night. There is currently
decent coverage of bands of showers and thunderstorms moving
across the area in the northeast flow. Expect this to continue for
the next couple of hours then diminish after the loss of daytime
heating, with the majority of shower activity through the night
shifting to off or just along the coast. 30 to 50 % pops early
will diminish to 15 to 30 after midnight. Some of the storms could
result in heavy downpours with precipitable water values around 2 inches. It will
be warm and muggy with lows in the lower to mid 70s across the
Short term /6 am Monday morning through 6 PM Monday/...
as of 400 PM Sunday...expect little change to the pattern with a
tropical depression approaching the area. With upper troffing and
ample moisture, expect another round of scattered showers and
thunderstorms to move across the area, blossoming in the late
morning to early afternoon with daytime heating. Currently
forecasting 30 to 50 pops across the area, but the trend may be to
increase that a bit. The showers/thunderstorms will generally be
on the move from northeast to southwest, not lasting too long in
any one location. However there is a good chance most of the area
will at least have a brief downpour, and in a few spots training
of the heavy showers could result in localized flooding issues.
Highs will be limited somewhat by cloud cover, but expect similar
temperature Sunday topping out in the mid 80s most places with a
few spots perhaps getting into the upper 80s.
Long term /Monday night through Sunday/...
as of 400 PM Sunday...slightly increased confidence in forecast
for Mon night-Thu night period with better model agreement on
approach of dew point 8 towards coast Mon night-Wed followed by a cold
front passage Thu and Thu night. Low confidence for Fri-sun period
with significant model differences in handling possible tropical
activity moving up out of Gulf of Mexico and affecting southeast
Monday night through Tuesday night...12z guidance continues to
show dew point 8, about 360 miles southeast of Cape Hatteras, moving
towards NC coast through Tuesday then moving north-northeast
Tuesday night. Some strengthening possible and tropical storm
force winds could affect mainly coastal waters as system
approaches. Main threat for land at this time appears to be local
heavy rain threat as periods of mainly scattered showers and
thunderstorms will affect most of area, with pops mainly 30-50%.
Partly to mostly cloudy skies will keep highs in mid to upper 80s
Tuesday with lows both nights mainly low to mid 70s.
Wednesday through Thursday night...models in general agreement
that dew point 8 will begin to move north and northeast Wed in response
to upper troughing approaching from northwest. This upper trough
will swing through eastern US Thu and Thu night pushing a surface
cold front through area. Scattered showers and tstms will remain
possible through period, but slightly higher chances ahead of
front Thu and Thu night. Low level thicknesses increase slightly
each day with inland highs mainly upper 80s Wed and around 90 Thu.
Lows still low-mid 70s Wed night then some cooling behind front
late Thu night with lows in upper 60s inland.
Friday through Sunday...models are in decent agreement that high
pressure will build in from northwest and north Fri and Fri night,
but then diverge with handling of possible tropical development
moving out of Gulf of Mexico. Given low confidence, used a blend
of previous forecast with mainly 12z superblend, indicating
lingering slight chance pops across area Friday and then just over
southern-most sections rest of period. Air mass expected to be
more comfortable with highs in 80s and lows in 60s inland to lower
Aviation /23z Sunday through Friday/...
short term /through Monday afternoon/...
as of 735 PM Sunday...aviation conditions will deteriorate to MVFR
levels this evening and to IFR levels in lowered ceilings and
vsbys by 06z. Pgv/isolated and to a lesser extent ewn/oaj observed
rainfall this afternoon, helping maintain a very moist low level
profile. Forecast soundings indicate a weak surface-based
inversion after 06z with light NE winds, which may decouple late.
Moderate confidence in IFR conditions between roughly 07-13z for
pgv/iso/oaj. VFR conditions should return between 13-14z, however
it is possible that MVFR conditions linger a few hours longer
given a weak wind field. Scattered showers and thunderstorms are
expected again Monday afternoon which may produce sub-VFR
conditions briefly at all taf sites.
Long term /Monday night through Friday/...
as of 400 PM Sunday...scattered to potentially numerous
showers/storms expected through at least Wednesday as dew point 8
approaches from southeast with periods of sub-VFR likely. Areas
of fog and stratus will be possible each night/early morning with
moist low levels and light winds. A cold front will push through
the area Thursday, with a drier airmass building into the region
short term /through Monday/...
as of 700 PM Sunday...no changes with update.
as of 400 PM Sunday...the big news on the marine forecast is an
approaching tropical depression. All mariners should monitor this
evolving situation as the forecast will likely change as the
situation evolves. The system is currently forecast to develop
into a low end tropical storm and may impact our coastal waters
beyond the short term.
Tonight into Monday the forecast will be influenced by high
pressure nosing across the area from the northeast. Between this
high pressure and the approaching depressions winds will remain
northeast tonight through Monday. Winds will be around 10 knots early
tonight gradually increasing to near 15 kt by morning, then 15 to
20 knots over portions of the central waters as the gradient tightens
with the approaching depression. Seas 3 to 4 feet early tonight will
build to 4 to 5 feet tonight in easterly swell associated with the
depression. By morning expect some 6 foot seas will be likely
along the central outer waters. With a combination increasing wind
waves and swells, expect 5 to 7 foot seas to develop on Monday
across the waters from around Oregon Inlet to Cape Lookout. Will
raise a small craft advisories for seas on this issuance.
Long term /Monday night through Friday/...
as of 400 PM Sunday...dew point 8 will approach from southeast through
Tue night and then move north-northeast Wed. Increasing NE winds
10-20 knots long period swell will combine to produce Small Craft Advisory
conditions for elevated seas mainly 5-7 feet into Tuesday evening.
Weaker pressure gradient will allow winds and seas to subside Tue
night-Thu, then increasing northeast winds behind frontal passage
late Thu night through Friday. Seas mainly 3-4 feet Wed-Thu then
building 4-5 feet northern waters Friday.
NC...beach hazards statement through Monday evening for ncz095-098-
Marine...Small Craft Advisory for hazardous seas from 2 am Monday to 11
PM EDT Tuesday for amz152-154-156.
Small Craft Advisory for hazardous seas from noon Monday to 2
am EDT Wednesday for amz150.
Small Craft Advisory for hazardous seas from 2 am Monday to 8
PM EDT Tuesday for amz158.