Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Newport/Morehead City NC
708 PM EST Thursday Feb 11 2016
weak low pressure will move across just south of the region on
Friday...followed by another blast of Arctic air for the
weekend. Low pressure will approach from the southwest Monday and
move across the area Tuesday. Weak high pressure will build in from
the west on Wednesday.
Near term /until 6 am Friday morning/...
as of 7 PM Thursday...forecast on track. No changes needed this
evening. Tonight will be the quiet before the storm as
temperatures drop quickly with very low dewpoints...that have
dropped into the single digits this afternoon. Expect lows in the
low/middle 20s area- wide as cloudiness increases from the southwest
after midnight. At this point...think any precipitation holds off
until after daybreak Friday.
Short term /6 am Friday morning through 6 PM Friday/...
as of 345 PM Thursday...a fast moving area of low pressure will
move just off the North Carolina coast during the day Friday into
Friday night. With a very cold airmass in place...wintry
precipitation will develop during the morning hours and continue
through late evening Friday. A Winter Storm Warning has been
issued for the north/northeastern County Warning Area for generally 1-3 inches of
snow along with some sleet. Further south and east the forecast
gets messy with a transition zone of snow/freezing rain/sleet in
the central County Warning Area and more of a rain/snow mix near the coast. If the
precipitation is able to arrive by early morning as some of the
composite reflectivity forecasts show from some of the various WRF
models and nam12...it will be falling into sub-freezing air. As a
result...also have a Winter Weather Advisory in effect for the
remainder of the County Warning Area from 12z Friday through midnight Friday
night. A number of complicating factors with this forecast. Some
of the guidance particularly the Canadian shows swath of heavier
snowfall further south and forecast soundings show a bit of a warm
nose developing during the afternoon which could lead to periods
of freezing rain/sleet which would cut down on any accumulations
of snow. As is usual in these types of situations...any small
deviation in the low track will lead to changes in the
precipitation type corridor and consequent amounts. Expect high
temperatures will remain at or below freezing in the warning area
in the northeastern County Warning Area...with some warming into the middle 30s
elsewhere...allowing for a transition to rain near the coast.
Probability of precipitation have been raised to the likely range.
Long term /Friday night through Thursday/...
below normal temperatures through early next week...with Arctic
airmass moving into eastern NC this weekend. Surface low will develop
over the Gulf states Monday and cross eastern NC Tuesday.
Friday night through sunday: a strong cold front will push through
the area Friday night into early Saturday...bringing even
colder/drier airmass into the region. Very strong high pressure will
build into the region from the northwest through the weekend. 850mb
temperatures will plummet by Sunday by the way -15c to -20c with low level
thickness dropping into the 1223-1240m range...resulting in very
cold temperatures. Saturday's highs: middle/upper 30s...and then upper
20s/low 30s Sunday. Overnight lows...mid/upper teens to low 20s
for both Saturday and Sunday. Wind chill values most likely will
be in the single digits Saturday night to Sunday morning across the
region. Some locations may break record for overnight lows Sunday
morning and low maximum value.
Monday through Wednesday...trough axis and surface high pressure will
shift offshore on Monday as the next shortwave comes in from the
Central Plains and develops a surface low over the Gulf states.Current
model run for GFS and European model (ecmwf) have some differences in regards to the
timing...strength of shortwave and surface low. Models have the surface low
tracking inland...increasing southerly flow across eastern NC. This
scenario could lead to possible strong/severe weather...but will not
mention it in the forecast. Have increased probability of precipitation to low chance
starting Monday and increased probability of precipitation for Monday night through Tuesday.
Precipitation could begin as -ra/-sn mix Monday morning before
transitioning to all rain.
The surface low is then expected to lift to the northeast late Tuesday
night. Models have a cold front will approaching the area Wednesday
and push through late Wednesday night/early Thursday. Surface high pressure
will build in behind the frontal passage. Temperatures will begin to
rebound Monday as highs are expected to reach into the 40s/low 50s
Monday... 50s Tuesday through Wednesday.
Aviation /00z Friday through Tuesday/...
short term /through 18z Friday/...
as of 7 PM Thursday...high confidence in VFR conditions through
much of the taf period. Clear skies prevailing into this evening
as a cold/dry Canadian airmass persists across the region. Middle
clouds will spread in late tonight as a shortwave moves into the
region. Low pressure will develop off the coast Friday morning
associated with the aforementioned shortwave aiding in
precipitation development across the region from south to north.
Given temperatures will be at or below freezing to start...have all taf sites
starting as -sn knowing the precipitation type will likely change
through the morning hours. Have visibilities/ceilings lowering throughout the
morning hours to MVFR. Current thinking is oaj to transition to a
wintry mix in the middle/late morning with this zone shifting to ewn.
Isolated/pgv will likely see more of a snow/sleet mixture through much
of the late morning/early afternoon. At this point...it is
splitting hairs as to the weather type and timing. So have just
introduced -sn at this point with the Assumption more detail will
be put into subsequent issuances. West- northwest winds will gusts
to 20 knots during peak heating today...diminishing late afternoon. Light
and variable winds overnight with light NE flow through Friday.
Long term /Friday night through Tuesday/...
as of 330 PM Thursday...flying conditions should slowly improve back to
VFR conditions will return late Friday night as a cold front pushes
through the area. High pressure builds in behind the frontal passage
and continues through Sunday. MVFR conditions is possible to return
Monday and continue through Tuesday as precipitation overspread the area as
a surface low lifts from the Gulf states.
short term /tonight and Friday/...
as of 7 PM Thursday...land/buoy observation show northwest winds 5-15
knots and waves 3-5 feet. Northwest winds become more north/NE later
tonight and subside a bit on Friday at generally 15 knots or less.
Seas at 3-5 feet now drop off to 2-4 feet Friday before increasing
again as another surge of cold Arctic air arrives this weekend.
Long term /Friday night through Tuesday/...
as of 330 PM Thursday...winds and seas will increase late Friday night/
early Saturday on the backside of the surface low and ahead of the cold
front. Small Craft Advisory conditions will re-develop late Friday
nigh/early Saturday into Sunday over the coastal waters/Pamlico
Sound. Northwest winds 20-30 knots with seas building 5-8ft. Winds are
expected to peak Saturday night into early Sunday...with possible
gale force wind gusts. Winds and seas will gradually diminish
briefly late Sunday into Monday...but increase back again as the
next system approaches Monday afternoon. Winds will veer on
Monday...becoming southeast 10-20kt with seas 3-5ft...then on Tuesday
southerly flow 20-30 knots and seas building 8-12 feet.
NC...Winter Weather Advisory from 7 am Friday to midnight EST
Friday night for ncz044-079-090>095-098-104.
Winter Storm Warning from 7 am Friday to midnight EST Friday
night for ncz029-045>047-080-081-103.