Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Newport/Morehead City NC
316 am EST Sat Nov 28 2015
high pressure will persist west of eastern North Carolina through
Sunday. A cold front will approach from the north Sunday night and
shift over the area on Monday. Weak low pressure will develop off
the coast Monday night and lift northeast Tuesday. A cold front
will approach from the west Tuesday night and move through the
region Wednesday. High pressure will build in from the northwest
Thursday. Low pressure will develop to the southeast on Friday.
Near term /until 6 PM this evening/...
as of 2 am Saturday...biggest weather concern this morning is fog which
may become dense at times across the coastal plains counties.
Clear skies led to formation of surface-based inversion early
yesterday evening which decoupled winds and allowed dewpoint
depressions to fall near zero most places. Have included mention
of dense fog possible in severe weather potential statement and may need to issue Special Weather Statement if coverage
becomes more widespread. Good radiational cooling will continue
early this morning with only a few thin cirrus moving in from the
northwest. Min temperatures will fall into the middle 40s inland to middle 50s
The surface ridge now resides more west of the area across the
Piedmont of NC/Virginia while the upper ridge over the northern Gulf of
Mexico continues to nose northeast into the region. These features
will remain across the region today with mostly sunny skies,
though fog may linger until 9 am EST for some inland locations due
to light winds. 1000-850mb low-level thicknesses increase near
1370 meters today which support maximum temperatures in the low/middle 70s
across inland portions of eastern NC with upper 60s along the
Short term /6 PM this evening through 6 am Sunday/...
as of 2 am Saturday...the surface ridge will slide south tonight
in response to a cold front slowly approaching from the northwest.
The upper ridge will also shift south of the region as weak zonal
flow takes over aloft. Increasing clouds should inhibit maximum
radiational cooling which will likely limit fog formation, despite
dewpoints in the upper 40s to low 50s with light boundary layer
mixing expected. MOS guidance and other high resolution data also
support a lower potential for fog tonight, so will leave out
mention in forecast for now. If clouds do not come in as expected,
fog could again become an issue tonight mainly for the coastal
plain counties of eastern NC. Minimum temperatures will fall into
the upper 40s inland to middle 50s along the coast/obx.
Long term /Sunday through Friday/...
as of 315 am Saturday...
Sunday...middle level flow becoming zonal through Sunday. Surface high pressure
will continue to weaken gradually and move south of the area as east
west oriented frontal zone drops south through the Middle Atlantic States.
The main band of associated deep moisture remains north of the area
through Sunday so should remain dry. Despite increasing afternoon
cloudiness, mild temperatures will continue Sunday with highs upper 60s to
low 70s most areas...little cooler NE CST/obx.
Sunday night through Tuesday...GFS/ECMWF fairly similar with
overrunning precipitation gradually developing late Sun night and Monday as
high pressure wedges into the area from the north. Both show best chances
across north and have a little higher probability of precipitation these areas. Have capped
probability of precipitation at high chance for now but later shifts may be raise to
higher categories if model trends hold. Even if higher probability of precipitation are
eventually introduced, rainfall amounts are expected to remain
fairly light (mainly less than half inch) given weak forcing through
Monday. Monday night and Tuesday weak low pressure develops near CST and
this will keep threat of scattered rain showers over region although model trends
suggest could taper off or end southern tier Tuesday. Thick cloud cover
will hold Monday highs in the middle 50s north and low 60s south.
Thicknesses rise a bit Tuesday with at least partial sunshine
developing and temperatures will rebound into the middle and upper 60s.
Tuesday night through Thursday...GFS/ECMWF differ a bit on timing
of cold front with GFS a bit faster pushing it offshore early Wednesday.
Will keep chance probability of precipitation going through Wednesday evening then ending Wednesday night.
High pressure will build in from the northwest Thursday with dry weather and pc to mclr
skies. Highs Wednesday upper 60s/low 70s then cooling into the upper 50s
Thursday night and Friday...deterministic model solutions show differences
with possible development of low pressure off the southeast coast late in
the week. For forecast continuity purposes, have maintained a low
chance pop for now given the wet GFS solution. However model ensemble
trends would suggest a dry (and cool) late week forecast period.
Aviation /08z Saturday through Wednesday/...
short term /through 06z Sunday/...
as of 130 am Saturday...poor aviation conditions expected early
this morning due to LIFR/IFR visibilities in fog. Decoupled winds with
clear skies and near surface saturation will allow fog to become
dense at times, especially at pgv/ewn adjacent to bodies of water.
Calm to light surface winds will continue until 14/15z this
morning meaning it will likely take some time for the fog to mix
out. VFR conditions expected after roughly 14/15z with light
northwesterly winds. Some guidance suggest fog may become an issue
again tonight though increased clouds should inhibit maximum
radiational cooling needed to support widespread/dense fog. Will
reassess fog potential for 12z taf issuance.
Long term /Sunday through Wednesday/...
as of 315 am Saturday...VFR conditions should continue through
the Sunday with limited moisture. High pressure nosing in from the north
will lead to some overrunning precipitation developing later Sun night
and continue into Monday. Coastal trf/low then expected to develop later
Monday into Monday night then lift north Tuesday. This will likely lead to
prolonged period of sub VFR starting Monday and continue into Tuesday as set
up looks favorable for stratus to develop...poss in IFR range.
Some scattered rain showers will continue through Tuesday as well. Cold front will approach
from west Tuesday night and cross Wednesday with continue threat of scattered rain showers and
occasional sub VFR.
short term /through tonight/...
as of 215 am Saturday...latest surface and buoy data indicate
light northwest to north winds, 5-10 knots, with long period
swells impacting the coastal waters, 5-8 feet around 11-12 seconds.
The surface ridge west of the waters will continue today then
shift southwest tonight, though winds will continue to remain
mostly 10 knots or less through tonight. Long period swells continue
today around 5-8 feet then begin to subside tonight with seas
mostly 4-6 feet by early Sunday morning. No change to current small
craft advisories at this time.
Long term /Sunday through Wednesday/...
as of 315 am Saturday...light northwest winds Sunday will shift north/NE and
increase to 15-20 knots and gusty as a cold front surges south through
the marine area late Sunday night and early Monday. The
combination of lighter winds and slowly subsiding swells will lead
to seas temporarily dropping below Small Craft Advisory levels Sunday morning
before building back above 6 feet again in the NE wind surge Monday.
Monday night and Tuesday tricky with track/intensity of low pressure off CST
in doubt...for now keep winds mainly in the 15 to 20 knots range
Monday night with direction becoming northwest and slowly diminishing Tuesday
on the back side of low pressure moving out to sea. Winds
diminish later Tuesday into Tuesday night as low departs with cold front
approach from west. Expect seas will drop below 6 feet all waters Tuesday
night. West-southwest winds early Wednesday will become more northwest late as front
crosses...speeds mostly at or below 15 kts with seas 3 to 5 feet.
Marine...Small Craft Advisory until 1 am EST Wednesday for amz152-154.
Small Craft Advisory until 7 am EST Sunday for amz150-156-158.