Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Newport/Morehead City NC
1017 am EST Monday Jan 26 2015
low pressure inland will move north and weaken today while
another area of low pressure develops off of the coast. The
offshore low will deepen rapidly as it lifts northeast away
from the area tonight and Tuesday. High pressure will build
in from the west Wednesday...then pass offshore Thursday.
A cold front will move through the area Thursday night into
Near term /until 6 PM this evening/...
as of 1015 am Monday...an area of light showers moving across the
Crystal Coast this morning coincident to an area of cooling cloud
tops along coastal sections evident on infrared satellite imagery. The
sub-cloud layer is very dry per the 12z kmhx sounding and most of
the reflectivity signatures are virga but knca reported a trace and
we got a trace at the National Weather Service office in Newport...so have increased
probability of precipitation to chance for the rest of the morning along the Crystal Coast
and obx south of Oregon Inlet. In addition...there is a line of
showers moving across Wilson...Edgecombe and Nash counties that
is producing a few lightning strikes...which could skirt far
northern Pitt and western Martin counties so have increased probability of precipitation
here and added thunder just for this area. Don't expect more
than a trace to 0.02" anywhere this morning. The only other chance
for the morning update was to capture T/dew point trends.
Previous discussion...still a complicated forecast next 36 hours
as Miller type "b" cyclogenesis takes place off of the NC coast
late today and tonight. Initial batch of precipitation associated
with the inland low pressure area to the northwest is moving
northward and should stay mainly to the west of the area early
this morning while another area of ongoing showers remains over
the near shore waters. The models are all over the place with
their precipitation forecasts for this afternoon but regardless of
where precipitation occurs it will be warm enough for rain. Think
best approach at this time is to indicate just a 30% pop as model
quantitative precipitation forecast forecasts are inconsistent and amounts are very light.
Although skies should remain mostly cloudy today the low level
flow is forecast to become southwest to west and this will help to
warm temperatures into the middle to upper 50s with lower 60s not out of
the question with some filtered sunshine.
Short term /6 PM this evening through 6 am Tuesday/...
as of 345 am Monday...the upper trough will become negatively
tilted as it crosses eastern NC overnight leading to rapid
deepening of the coastal low as it move up the East Coast. These
series of events will allow cold air to be circulated into eastern
NC after midnight with freezing levels lowering to under 1000 feet
by 12z Tuesday. Thus any remaining precipitation would be able to
mix with and eventually change to snow especially over the
northern half of the area. Again the models are not in agreement
with quantitative precipitation forecast placement with amounts less than 0.25" indicated. This in
combination with surface temperatures expected to remain above
freezing and relatively warm ground temperatures will preclude any
significant accumulations and impacts. We could see a few tenths
of an inch accumulation on grassy surfaces/elevated roadways. May
need to raise probability of precipitation to likely after taking a closer look at 00z European model (ecmwf).
Long term /Tuesday through Sunday/...
as of 345 am Monday...strong vert stacked low will continue to deepen
and move up the eastern Seaboard Tuesday...while deep upper trough
continues across the East Coast. Moisture will continue to wrap
around the system Tuesday...and while moisture continues to look
limited there will be the potential for a brief period of winter
weather. Thermal profiles and critical thickness values indicate the
precipitation transitioning to primarily light snow/snow showers Tuesday
morning across eastern NC. Temperatures will generally remain the 30s Tuesday
morning and only warming to around 40-45 during the afternoon.
With surface temperatures above freezing much or all of the period...still
expect minimal impacts with little to no snow accumulation. The
Albemarle Sound region and the northern obx will have the best chance
to see some light accumulation as this area will be under the
deeper wrap around moisture the longest...but with the relatively
warmer antecedent conditions any accumulation expected to be
confined primarily to grassy and elevated surfaces. With light quantitative precipitation forecast
amounts...not expecting more than a dusting at any location.
Precipitation will likely transition back to a rain/snow mix Tuesday
afternoon as surface temperatures warm to around 40.
Moisture moves offshore Tuesday night and Wednesday with dry conditions and
mainly clear skies. High pressure builds into the region Wednesday and Wednesday
night...then shifts offshore Thursday as the next clipper system
approaches from the northwest. Lows Tuesday night and Wednesday night will
be in the middle 20s inland to lower 30s along the coast. Highs Wednesday
around 40-45 with about 5-7 degrees warming for Thursday. Confidence
below average with a couple late period northern stream clipper systems
as models not in best agreement with the strength and available
moisture. The first system will move across the region Thursday night
into Friday. The GFS is weaker and has limited moisture with this
system while the European model (ecmwf) is deeper with the middle- level shortwave and
taps more Gulf moisture and subsequently wetter across eastern NC.
Increased probability of precipitation to low chance Thursday night. High pressure builds across
the area late Friday through Sat. Below normal confidence continues
late next weekend with the potential for another low to develop
along the southeast coast. Model differences continue with the GFS about
18-24 hours faster than European model (ecmwf) moving the low along the NC coast.
Temperatures through the period expected to be below normal with mainly
40s for high...except Friday when temperatures expected to climb to the
lower 50s central and southern sections.
Aviation /15z Monday through Friday/...
short term /through tonight/...
as of 615 am Monday...high confidence in VFR conditions through
this afternoon as precipitation associated with weakening inland
low pressure remains just west of the taf sites today while
another area remains just off of the coast. Expect middle and high
level cloudiness for most of the day with cloud bases lowering
late in the day as low pressure begins to develop off of the
coast. Negatively tilted upper trough crosses the region tonight
as coastal low begins to rapidly deepen of of the del marva.
Associated moisture should increase across the region with showers
developing a couple hours either side of 00z. Expect MVFR
conditions to develop during this time with a potential for IFR
ceilings after 06z. Deepening cold air will change light rain
showers to snow showers toward dawn Tuesday with best threat
across the northern taf sites.
Long term /Tuesday through Thursday/...
as of 345 am Monday...sub-VFR conditions to start out the period
Tuesday...with MVFR ceilings likely. Light snow showers possible
Tuesday morning...though little to no accumulation expected with
best chances for light accumulation northeast of the terminals.
Conditions will be gradually improving Tuesday afternoon...becoming
pred VFR by late Tuesday afternoon and continuing into Friday. A cold
front will move through the terminals late Thursday night into Friday
with scattered showers possible.
short term /through tonight/...
as of 615 am Monday...small craft advisories have been issued for
all of the near shore waters/the sounds/ and The Alligator river. A
brief period marginal gales are possible over the central waters
late tonight into early Tuesday. Miller type "b" cyclogenesis off
of the NC coast during the next 24 hours will lead to hazardous
winds and seas developing tonight. In the meantime light easterly
flow north of Ocracoke will become southwest while south of there
winds will continue west-southwest 10 to 15 knots. This evening the flow
will become northwest and increase to 25 knots with higher gusts as
rapidly developing low pressure moves up the East Coast leading to
building seas of 6 to 8 feet by early Tuesday morning.
Long term /Tuesday through Friday/...
as of 345 am Monday...unsettled conditions expected on the waters
through mid-week. Strong vertically stacked low pressure system
will continue to move up the East Coast Tuesday. North-northwest winds will
remain strong...15-25kt gusts 30-35kt...through midweek as low
deepens to the northeast and reinforces the pressure gradient
along the NC coast. Small Craft Advisory conditions expected to continue into
Wednesday/Wednesday night. Winds will begin to diminish and back to the west/SW as
surface high pressure shifts offshore late Wednesday night and Thursday. The
potential for Small Craft Advisory conditions return late Thursday night and Friday as a
cold front moves through the waters. Used a blend of wavewatch and
local nwps as the nwps is usually overdone in northwest flow situations.
Elevated seas of 6 to 9 feet expected Tuesday and Wednesday...highest central
and northern waters before gradually subsiding through Thursday.
Persistent gusty north-northwest flow...tonight through Wednesday...could
result in minor water level rises for sound-side areas of the
Outer Banks adjacent to the Pamlico Sound.
Marine...Small Craft Advisory from 7 PM this evening to 4 PM EST
Tuesday for amz135.
Small Craft Advisory from 7 PM this evening to 10 am EST
Tuesday for amz130-131.
Small Craft Advisory from 7 PM this evening to 4 am EST
Thursday for amz150-152-154.
Small Craft Advisory from 7 PM this evening to 7 PM EST
Wednesday for amz156-158.