Area Forecast Discussion
Issued by NWS Newport/Morehead, NC

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FXUS62 KMHX 040816

Area Forecast Discussion
National Weather Service Newport/Morehead City NC
316 AM EST Sun Dec 4 2016

High pressure will build over our area from the north through
Sunday then move offshore Sunday night. Low pressure will move
quickly up the coast Sunday night. High pressure will briefly
build in Monday. Another area of low pressure will affect the area
late Monday night through Tuesday. High pressure will build in
mid week. A strong cold front will move through late in the week.


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.

/Previous discussion/
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 SE 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.


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 /Monday through Sunday/...
As of 316 AM Sun...Rain will move offshore during the morning
Monday. A break expected in the rain Monday afternoon through
evening before another round moves through late Monday night
through Tuesday. Dry and warm mid week followed by a strong cold
front and arctic air Friday into next weekend.

Monday...Good model consensus with respect to first round of rain
moving offshore Monday morning. High pressure will nose into E NC
Monday afternoon through early evening with dry conditions.
Thicknesses/hts do rise a bit behind the exiting system despite
wind switch to the NW. Highs should reach the 55-60 degree range.

Monday Night into Tuesday...Strong compact shortwave trough will
eject out of the southern plains Monday night and move through the
TN/OH valley Tuesday. 04/00Z model suite remains in good
agreement with this system bringing another round of rain during
this time frame. Strong omega develops late Mon night as
strengthening S flow develops on 50 kt LLJ. 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 advancing towards E NC will spread in rain from west to
east after midnight and have an increasing pop trend through the
overnight as a result. First half of Tue will be a washout as deep
moisture/lift is maximized over the area. Second area of
cyclogenesis progged to develop along the NC coast and quickly
exit on Tuesday with winds becoming NW behind the exiting system.
It will be warm despite the rain with highs in the 60s east to
mid/upr 50s coastal plain which should remain in northerly flow on
cool side of the low.

Tuesday Night through Thursday...Dry conditions return with
subsidence and advancing high pres behind the departing system.
It will continue to be mild as upr ridge amplifies across the
eastern CONUS in response to deepening trough across the
Intermountain West and Plains states. Temps above climo expected
with highs in the 60s and lows in the mid 40s to lower 50s.

Friday through Sunday...Aforementioned trough across the
western/central CONUS will translate eastward bringing coldest
air mass of the season to much of the eastern 2/3 of the CONUS.
Strong cold front will push through E NC by Fri with strong CAA
ensuing behind it. Blustery and cold conditions expected Friday
through Sat with high temps in the 40s and lows 20-25 interior to
low 30s OBX.


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
CIGS will lower to VFR SCU this afternoon, then MVFR to IFR likely
this evening as air mass becomes saturated.

Long Term /Monday through Friday/...
As of 316 AM Sun...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
afternoon and evening though low clouds and fog may persist on Tue
night. High pres builds in for Wed into Thur bringing return to
VFR conditions. Strong cold front will push through Thur night
into Fri with gusty NW winds developing behind it.


Short Term /through Sunday/...
As of 915 PM Saturday...High pressure will continue to build over
the waters through Sunday. N/NW 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 SCA 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 N/NE 5-15 knots with seas
generally remaining 2-4 feet.

Long Term /Monday through Friday/...
As of 316 AM Sun...Weak coastal low pres trough moves offshore on
Monday with winds becoming NW and gusty behind it. It now appears
enough of a gradient develops to produce SCA winds/seas north of
Hatteras. A stronger low pres area develops and moves up the coast
on Tue, bringing strong gusty winds and probable SCA 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, but it appears gusty
easterly winds ahead of the low will then switch to the NW and
remain gusty as the low exits. The low will exit Tue night with
winds diminishing on Wednesday. Winds back to the SW or W by Thur
with approach of strong cold front that will move through the
waters Thur night or Fri bringing another round of gusty 20-30 kt
winds in its wake.




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