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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KMHX 141135
AFDMHX

Area Forecast Discussion
National Weather Service Newport/Morehead City NC
635 AM EST Fri Dec 14 2018

.SYNOPSIS...
A strong storm system will affect the area today into the
weekend. High pressure will gradually build in from the west
early through mid next week. Another storm system may impact the
area late next week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
As of 635 AM Thursday...A cut off upper low is forecast to
slowly track from the Gulf coast today, to Alabama tonight, then
East TN Sat. At the surface, a coastal warm front will move
inland today and tonight as high pressure moves out into the
Atlantic. As this boundary moves across the area, an area of low
pressure will move northeast along it across the coastal plain
of NC tonight. Moisture will advect into the area from the Gulf
of Mexico and the Gulfstream with PW values increasing to around
1.75" by early evening which is near the climatological maximum
for mid-December. Warm advection will be increasing ahead of
the advancing upper low and combined with increasing upper level
divergence ahead of the upper low will produce strong lift
across eastern NC beginning this afternoon. This will eventually
lead to the development of widespread rain showers across most
of the area this afternoon. Dry air currently over the area will
initially limit rainfall intensity through early afternoon,
with heavier rains then expected to develop by evening
especially across the western portion of the region. With the
dry air persisting longer along the Outer Banks, we are
expecting less in the way of precipitation today and there will
be a large gradient in PoPs/QPF with highest over the western
half of the region.

Temperatures are forecast to slowly rise today with daytime
highs expected late as southerly flow develops and
strengthens. Highs will range from the upper 50s across the
northern coastal plain to the mid 60s coast.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
As of 635 AM Friday...Very active weather is expected across
Eastern NC tonight and Saturday. Extreme values of PW for this
time of year combined with strong ascent and confluent low level
flow will lead to widespread heavy showers and possible strong
to severe thunderstorms, especially along the coast where
instability is forecast to be greatest. Rainfall amounts of 2-3
inches, with locally heavier mounts will be possible by Sat
evening. Thus will continue current Flash Flood Watch for the
entire area due the expected heavy rains and already saturated
soils. In addition, the strong kinematic environment with
increasing wind fields will produce 0-6km bulk shear around 40-
50 kt, however instability will be lacking with MUCAPEs forecast
AOB 500 J/kg. Damaging wind gusts and isolated tornadoes are
threats in this high shear/low CAPE environment tonight into
early Sat afternoon. The precipitation is forecast to taper off
from west to east late Sat.

With increasing southerly flow temps will likely continue to
rise tonight with the 24 hr max temps occurring overnight.
Temps may level off late tonight then increase diurnally Sat.
Readings will be well into the 60s during this time with some
guidance suggesting temps possibly rising into the 70s Sat.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
As of 330 AM Friday...An upper low will track just north of the
area through Sunday with additional isolated to scattered
showers possible. High pressure builds in from early to the
middle of next week. Another storm system is expected to
approach the area late next week.

Saturday night through Sunday night...The upper cut-off low
will track from the southern Appalachians to just north of the
area this period with additional cyclogenesis occurring just off
the mid-Atlantic coast ahead of the trough. Deeper moisture
expected to slide offshore by Saturday evening with PW values
dropping to less than an inch but could see isolated to
scattered showers across the area this period with steep mid-
level lapse rates invof the upper low and vort maxes that may
rotate through the upper low as depicted in some models. The
00z ECMWF has come into agreement with other models tracking the
low just north of the area, lifting from the Piedmont across SE
VA Sunday. Have chance PoPs area wide Saturday evening, but
gradually taper PoPs down through the rest of the period. Temps
will be cooler Saturday night than the previous night but still
around 10-15 degrees above normal from around 50 inland to lower
50s coast. Temps cool to just above climo Sunday and Sunday
night with highs in the mid 50s to around 60 and lows in the low
to mid 40s.

Monday through Wednesday...A strong northern stream jet digging
into the Great Lakes and Northeast will allow the upper low to
quickly lift NE away from the area early next week with surface
high pressure building into the region from the west bringing
dry conditions for the first half of the work week. Temps will
continue around or a little cooler than climo with highs
generally in the 50s and lows in the 30s.

Thursday...The next storm system is progged to approach the area
for the latter half of next week, however there remains
substantial spread in the models at this time whether northern
stream energy digging across the Northern Plains into the
Midwest will phase with a mid-level trough/low pressure over the
Southern Plains to develop a longwave trough across the eastern
CONUS. This solution will bring a strong Gulf moisture feed
into the area potentially bringing another round of heavy
rainfall across the area as shown in the 00z operational ECMWF
and CMC. If phasing doesn`t occur and the northern stream
dominates, the Gulf moisture tap will be cut off and would
likely see a dry frontal passage late in the week as depicted
by the operational GFS. Due to the uncertainty have followed WPC
guidance closely late next week.

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
Short Term /through Tonight/...
As of 635 AM Friday...VFR conditions should continue into the
afternoon, then cloud bases and visibilities will lower and
should drop to MVFR levels by late afternoon as showers become
widespread across the region. IFR conditions will then be likely
tonight in moderate to heavy rain showers.

Long Term /Saturday through Tuesday/...
As of 4 AM Friday...A strong low pressure system will slowly
move across the region through the weekend bringing periods of
sub-VFR conditions. The heaviest rain/lowest cigs/vsbys expected
though Saturday morning. Conditions begin to improve late
Saturday but additional showers will be possible Saturday night
and Sunday with periods of sub-VFR conditions possible at
times. High pressure builds in from the west early next week
with pred VFR conditions expected.

&&

.MARINE...
Short term /through Saturday/...
As of 635 AM Friday...No changes to previous forecast thinking.
SCA`s continue in effect for the near shore waters and Pamlico
Sound as marine conditions are forecast to slowly deteriorate
this afternoon and tonight as a complex storm system moves into
NC. Winds are currently light north of Bogue Inlet and mainly
from the E early this morning with seas running 2-4 feet in long
period (10-13 second) swells. Expect increasing winds and
building seas through the day today. E/SE winds 10-20 kt
increasing to 15-25 kt during the afternoon and evening then
becoming S late tonight 20-25 kt late tonight and early Sat.
Seas are forecast to build to 5-8 ft south of Oregon Inlet and
3-5 ft north. Tonight into early Sat seas build further to 7-11
ft. Sat afternoon winds are forecast to become SW 15-20 kt with
seas slightly subsiding to 5-8 ft late.

Long Term /Saturday night through Tuesday/...
As of 415 AM Friday...SW winds around 5-15 kt Saturday night
will slowly veer to W around 10-20 kt Sunday, the NW Sunday
night. Could see winds as high as 20-25 kt across the northern
coastal waters Sunday night as low pressure develops off the
mid-Atlantic coast. Gradients remain tight into early next week
with a surface trough progged to push across the waters Monday
night. Winds back to west around 10-15 kt Monday, then become NW
around 15-25 kt Monday night after the passage of the trough,
then winds gradually diminish through the day Tuesday. Seas
around 5-9 ft Saturday evening gradually subsides to 3-6 ft by
late Sunday and 3-5 ft Monday but build back to 4-6 ft across
the northern/central waters Monday night and Tuesday with the
secondary surge.

&&

.HYDROLOGY...
As of 330 AM Friday...Flash Flood Watch will continue for all
of Eastern NC with heavy rainfall amounts of 2-3 inches
expected to fall during the upcoming storm system fro late today
into Saturday. The highest rainfall totals are expected along
the coast where some isolated amounts of 4 + inches are
possible. The heaviest precip will fall overnight into Saturday,
and given the very saturated ground, there will likely be
flooding of poor drainage areas, and the potential for localized
flash flooding. Local streams and rivers are already running
near or above flood stage, and the expected rainfall will lead
to additional river flooding across Eastern NC.

&&

.MHX WATCHES/WARNINGS/ADVISORIES...
NC...Flash Flood Watch from 1 PM EST this afternoon through
     Saturday afternoon for NCZ044-079-090>095-098.
     Flash Flood Watch from 4 PM EST this afternoon through
     Saturday afternoon for NCZ029-045>047-080-081-103-104.
MARINE...Small Craft Advisory from 7 PM this evening to 10 AM EST
     Saturday for AMZ135.
     Small Craft Advisory from 7 PM this evening to 9 AM EST Monday
     for AMZ150.
     Small Craft Advisory from 2 PM this afternoon to 5 PM EST
     Monday for AMZ152-154.
     Small Craft Advisory from 11 AM this morning to midnight EST
     Sunday night for AMZ156-158.

&&

$$
SYNOPSIS...MHX
NEAR TERM...JME
SHORT TERM...JME
LONG TERM...SK/SGK
AVIATION...JME/SK
MARINE...JME/SK
HYDROLOGY...MHX