Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Newport/Morehead City NC
150 am EST sun Dec 4 2016
high pressure will build over our area from the north through
Sunday then move offshore Sunday night. Several areas of low
pressure will affect the area Sunday night through Tuesday. High
pressure will build in mid week. A strong cold front will move
through late in the week.
Near term /until 6 am this morning/...
as of 100 am Sunday...updated to increase cloud cover and raise
temps as clouds will limit additional cooling rest of night.
Abundant radar returns west of Fay-cae line and spreading east but
atmospere of eastern NC very dry in low and mid levels and threat
of measurable rain will hold off until during the day Sunday.
as of 915 PM Saturday...surface high pressure will continue to
ridge south into our area from the Great Lakes region overnight.
Well out ahead of an advancing mid level trough, widespread high
clouds have been advancing east over the southeast states and will
continue to do so overnight with bases lowering to mid cloud
levels after midnight. Regional radar mosaic shows a rather
substantial area of returns over South Carolina and portions of
extreme southern NC. Most of this precipitation was evaporating
before reaching the ground or falling as sprinkles from a mid
cloud deck and will be encountering established surface high
pressure over central and eastern NC producing a large area of dry
air below 550 mb /as seen in the mhx 00z sounding/, thus do not
expect any measurable precipitation across eastern NC overnight
though a few sprinkles are possible over southern areas late. Main
affect will be to limit radiational cooling. Thus expect
temperatures to fall for the next 2-4 hours this evening when the
clouds are less opaque, then readings should level off or perhaps
rise a little after midnight with thicker/lower based cloud cover.
Still expecting overnight lows to range from the mid to upper 30s
inland to lower 40s Outer Banks.
Short term /6 am this morning through 6 PM today/...
as of 550 PM Saturday...main concern Sunday is timing
precipitation onset as deeper moisture advection and isentropic
lift increase rapidly during the afternoon in response to
developing warm advection. Complicating the forecast is the dry
sub cloud layer as depicted by forecast soundings, which will
initially evaporate most of the rain that falls thus we are
expecting quite a bit of virga. Think after 20z measurable light
rain should occur over the extreme western zones with trace
amounts expected as far east as a Cape Lookout to Alligator river
line just prior to 00z. Despite slightly higher thickness values
on Sunday, cloud cover/evaporating precipitation will hold
maximum temperatures into the low/mid 50s.
Long term /tonight through Saturday/...
as of 330 am Sat...a wet pattern Sunday night through Tuesday,
followed by mainly dry and warm mid week. A strong cold front
moves through late week bringing the coldest air of the season for
Sunday night...good model agreement with regards to widespread
rain spreading through east NC Sun night, and have likely pops area
wide. Large area of decent isentropic lift develops courtesy of
strengthening of swrly low level jet and spreads rain across the entire
area. Some of the energy will go into moistening of the dry low
levels but this should be overcome by evening as entire column
saturates prior to 06z.
Monday...there may be a break in the precip on Monday as area of
lift moves offshore and winds back to the north with high trying
to nose into the area from the Great Lakes region. Think skies
will remain mostly cloudy however as already next larger system to
the west develops and moves this way. Thicknesses/hts do rise a
bit and expect temps in the 55-60 degree range, held down a bit
due to the mostly cloudy skies. Have low chc pops across the north
where influence of high is stronger, to 40-50 percent across the
south where deeper moisture and MO cloudy skies persist.
Monday night into Tuesday...strong compact shortwave trough will
eject out of the Southern Plains and move NE Monday night into
Tuesday. 03/00z model suite remains in good agreement with this
system bringing periods of rain during this time frame. Strong
Omega develops by Mon night as strengthening S flow develops on 50
kt low level jet. The region will be in rrq of upper jet and will induce
large area of div q over the region. Deep southerly flow
downstairs combined with large area of Omega will produce
widespread rain later Mon night into Tue and have raised pops to
categorical as a result. Up to an inch or two may fall over most
of the forecast area through this time frame. Mild temps expected with lows
in the upper 40s/lower 50s and highs in the 60s.
Tuesday night through Thursday...system will exit by Tue night
into Wed bringing end to showers with a return to dry conditions.
It will continue to be mild behind this system as upr ridge
amplifies across the eastern Continental U.S. In response to deepening trough
across the intermountain west. Temps above climo expected with
highs in the 60s and lows in the mid 40s to lower 50s.
Friday through Saturday...aforementioned trough across the
intermountain west will translate eastward bringing coldest air
mass of the season to much of the eastern 2/3 of the Continental U.S.. strong
cold front will push through east NC by Fri with strong cold air advection ensuing
behind it. Blustery and cold conditions expected Friday through
Sat with high temps in the 40s and lows 20-25 inland to low 30s
Aviation /07z Sunday through Thursday/...
short term /through 06z Monday/...
as of 100 am Sunday...high confidence in mainly VFR conditions
rest of night and through the day Sunday, but lower cigs and vsbys
likely developing this evening with widespread rain. Mid level
ceilings will lower to VFR scu this afternoon, then MVFR to IFR likely
this evening as air mass becomes saturated.
Long term /Sunday night through Thursday/...
as of 330 am Sat...ceilings will lower to sub VFR Sunday night
with widespread rain developing. Skies may lift to VFR on Monday
though lower again Monday night into Tuesday with strong low
pressure moving across the area and more widespread rain. The low
will exit Tue night though low clouds and fog may persist on Tue
night. High pres builds in for Wed into thur.
short term /through Sunday/...
as of 915 PM Saturday...high pressure will continue to build over
the waters through Sunday. North/northwest winds continue overnight at 10-15
knots. Seas have subsided to 4-5 ft at the buoys over the northern
and central waters so will cancel the Small Craft Advisory early with the 10 PM
update. Elsewhere, seas are forecast to subside to 2 to 4 ft. As
the high pressure system transits east across the area Sunday
afternoon, winds will diminish to north/NE 5-15 knots with seas
generally remaining 2-4 feet.
Long term /Sunday night through Thursday/...
as of 330 am Sat...weak coastal low pres trough moves through on
Monday with winds becoming SW south of Hatteras though remaining east
to NE across the northern waters and sounds. Winds and seas should
remain sub Small Craft Advisory. A stronger low pres area moves through the region
on Tuesday, bringing strong gusty winds and probable Small Craft Advisory
conditions. Tough to pin down the speed and direction of winds at
this time as the low will be passing through the marine domain
making timing of wind switch difficult this far out in time. The
low will exit Tue night with winds becoming northwest and diminishing on
Wednesday. Winds back to the SW and west by thur with approach of
strong cold front that will move through the waters late week.