Greenville, North Carolina 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

325
FXUS62 KMHX 180242
AFDMHX

Area Forecast Discussion
National Weather Service Newport/Morehead City NC
942 PM EST Fri Jan 17 2025

.SYNOPSIS...
High pressure overhead will push offshore tonight. A coastal
low will pass offshore on Saturday, followed by a stronger low
moving through on Sunday. A strong cold front then pushes
through the area Sunday night. High pressure then builds in on
Monday. By mid-week, another area of low pressure is forecast to
pass well offshore of the Southeast U.S. coastline.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
As of 10 PM Friday...No major changes to the forecast with this
update. Temps rapidly cratering with the loss of daytime
heating, even for OBX. Adjusted fcst temps down through early
tomorrow morning.

Previous Discussion...As of 220 PM Fri...Latest analysis shows
1022mb high pressure centered over eastern NC, with front moving
through the central US. Sfc high and upper ridge will grad push
offshore tonight, while dampening shortwave approaching the
Appalachians induces cyclogenesis off the SE coast early Sat
morning. Ahead of the front, both moisture advection and WAA
will commence as the evening progresses. This will allow for two
things to happen. The first will be a pre- midnight low with
temps quickly falling into low 30s to low 40s after sunset and
then becoming either steady or warming slightly after midnight
towards daybreak. The second will be a quick increase in mid and
high cloud cover as well as the potential for increased
isolated shower chances as moist return flow allows for the
column to moisten rather quickly. Rain chances increase along
the immediate coast early Sat morning.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
As of 220 PM Fri...A dampening shortwave moving through the
central and southern Appalachians will induce low pressure
development off the SE coast Saturday. Guidance continues to
show a consistent signal keeping this low offshore as it lifts
NE past ENC. Despite notable large-scale forcing, the best
overlap of moisture and low-level convergence looks to be
focused near and just offshore, which continues to favor the
coastal areas for the best chance of showers, and the highest
rainfall amounts (up to 0.50"). Further inland, we still expect
showers to develop, but it continues to look a bit drier there
compared to the coast. Moderately strong WAA plus a modest
southerly flow will help boost temps into the 50s.

&&

.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
As of 300 AM Friday...

KEY MESSAGES:

 - Notable arctic airmass to invade ENC next week

 - Confidence in wintry weather remains moderate for next week

Saturday night - Sunday night:

On Sunday, yet another upper level wave will glance the area,
and will once again spur on cyclogenesis, leading to the
development of a secondary area of low pressure. The track of
this low looks to be further inland as it runs NE from southern
Alabama through eastern North Carolina. This inland track should
help keep temps on the milder side for one more day, which also
favors all liquid during the daylight hours Sunday. As the low
moves up the Mid-Atlantic Coast, it will deepen, allowing strong
CAA to ensue across ENC. This continues to look like a cold-
air-chasing-the-moisture scenario, with rain showers possibly
ending as a brief period of snow showers north of HWY 264. Most
ensemble guidance shows no snow accumulation Sunday night, and
our forecast will reflect this expectation.

Monday - Thursday: In the wake of Sunday`s cold front, an arctic
airmass will ooze south and east out of Canada and blanket much of
the U.S. east of the Rockies for several days. Meanwhile, an upper
level shortwave (currently passing south of Alaska) will dive
southeast along the Rockies on Monday, then translate east across
the Gulf Coast States Tuesday or Wednesday. Medium range guidance
are in solid agreement with the wave as it dives through the
Rockies. However, more notable differences begin to show up as it
crosses the Gulf Coast States. The latest suite of guidance
now appear to fall into 2 camps, each outlined below.

SCENARIO #1 - The upper wave remains positively-tilted, and
progressive, as it traverses the Southeast U.S. This scenario favors
a weaker, faster, and more suppressed, low track from the Gulf of
Mexico east into the SW Atlantic. This scenario supports the
potential for a glancing swath of light, accumulating snow, across
parts of ENC, with the greatest risk along the coast, and a
decreasing chance further inland. This currently appears to be the
most likely scenario, and this is the scenario reflected in our
latest forecast. One caveat in this scenario is that if the low is
too far suppressed to the south, ENC would just remain cold and dry,
with little to no snow.

SCENARIO #2 - The upper wave slows down as it emerges out of the
Southern Rockies, and takes on a negative tilt before translating
across the Southeast U.S. This scenario favors a deeper surface low
over the Gulf, with a subsequent track closer to the Gulf and
Southeast U.S. coastline. For ENC, this would be the more impactful
scenario, as it would potentially open the door for a period of
moderate to heavy wintry precip. This scenario currently appears to
be the least likely. One caveat in this scenario is that a deeper
low that tracks too close to the coast could introduce more warmer
air and less wintry weather, especially along the coast.

The upper level wave in question still has a long way to go, and the
downstream pattern may still change before it reaches the Southeast
U.S. But, the above scenarios present the latest spectrum of
possibilities based on the latest guidance. Please continue to stay
tuned through the weekend and into next week.

Lastly, what remains most confident is the anomalously cold airmass.
A stretch of unusually cold temperatures still appears likely, with
record or near-record temperatures very much on the table.
Additionally, 24-36+ consecutive hours of below freezing
temperatures, plus multiple nights with lows in the teens, has the
potential to take its toll on pipes and other infrastructure not
accustomed to this magnitude of cold. Precautions are strongly
recommended in preparation of this stretch of cold weather. Of note,
too, if we do end up getting any accumulating snow, temperatures
could end up even colder.

&&

.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM /through Saturday/...
As of 7 PM Fri...Pred VFR conditions to start the night, as high
pressure gradually continues moving offshore. Flow switches to
become southerly early morning Saturday, ushering in moisture
and warm air advection. In this regime, a band of MVFR CIGs
could develop, gradually moving from south to north, between
8-12Z. Chances of this are low enough were I stuck with SCT030
in the TAFs with this update instead of going BKN/OVC, but this
will have to be monitored. Outside of this brief window of sub-
VFR potential, VFR returns after 12Z. around 14Z, potential for
widespread sub-VFR develops with light to occasionally moderate
rain. Sub-VFR conditions are expected to linger across much of
the area through Saturday evening ahead of another round of
rain moving in from the south.

LONG TERM /Saturday night through Wednesday/...
As of 300 AM Friday...

KEY MESSAGES:

 - Increased risk of sub VFR conditions this weekend

 - Monitoring Tuesday/Wednesday for possible wintry weather

Scattered to numerous SHRA are expected Saturday night and
Sunday as a pair of low pressure systems track across the
region. By Sunday night, cold air wrapping into the area may
allow a change from SHRA to SHSN, mainly in/around KISO/KPGV.
Accumulations of snow are not expected Sunday night. Periods of
low CIGS and low VIS are expected over the weekend, with the
greatest risk of IFR, or lower, conditions coming on Sunday.
Gusty northwest winds will be possible with a cold front as it
moves through Sunday night. A drier airmass moves in on Monday
with VFR conditions and lighter winds expected. Looking ahead,
there is a moderate chance (40-60%) of wintry weather Tuesday or
Wednesday of next week, along with the potential for IFR, or
lower, conditions. Stay tuned as we continue to evaluate this
potential impact to aviation.

&&

.MARINE...
SHORT TERM /through Saturday/...
As of 220 PM Fri...Latest obs show N/E winds 5-15 kt with seas
3-5 ft. High pressure overhead will grad shift offshore tonight
as another cold front approaches. Low pressure will strengthen
off the coast Saturday. Winds grad veer overnight becoming S/SE
10-20 kt becoming SW-NW 10-15 kt by Sat afternoon. The central
waters could see a few hours of gusts to 25 kt near the Gulf
Stream early Sat morning, though right now looks too marginal
for SCA. Seas will subside to 2-3 ft tonight, then 2-4 ft Sat.

LONG TERM /Saturday night through Wednesday/...
As of 300 AM Friday...

 - Risk of elevated winds and seas increasing for Sunday and Monday

A pair of low pressure systems will move northeast through the ENC
waters, leading to an increased risk of showers, elevated winds, and
elevated seas. A few thunderstorms will be possible as well,
especially the coastal waters between Cape Lookout and Cape
Hatteras. The highest risk of SCA and/or gale-force winds appears to
be late Sunday into Monday as the deepest of the two lows moves
through. High pressure eventually builds in later Monday into Monday
night with some improvement to boaters for a brief time.

&&

.MHX WATCHES/WARNINGS/ADVISORIES...
NC...None.
MARINE...None.

&&

$$

SYNOPSIS...MHX
NEAR TERM...CQD/RJ
SHORT TERM...CQD
LONG TERM...RM
AVIATION...RM/CQD/RJ
MARINE...RM/CQD