Area Forecast Discussion
Issued by NWS Newport/Morehead, NC

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FXUS62 KMHX 230227

Area Forecast Discussion
National Weather Service Newport/Morehead City NC
1027 PM EDT Sun Oct 22 2017

High pressure will extend into the region from the northeast
through Monday. A strong cold front will approach from the west
Monday night and move across the area through Tuesday night.
High pressure will build over the area Wednesday through Friday.
Another cold front will approach next weekend.


As of 1025 PM Sunday...The latest sfc analysis continues to
show sfc high pressure dominating the area this evening with
scattered clouds moving along the coast, meanwhile high clouds
are streaming through. Winds are now light to calm across ENC
and will continue through the overnight. Expect some patchy fog
to develop over the NW sections of Eastern NC. Made minor tweaks
to the overnight lows with this update based on warmer trends,
but expect lows in the upper 50s to mid 60s along the coast.


As of 330 PM Sunday...SE-S flow and approaching strong short
wave trough will produce increasing shower threat during the day
with enough instability to warrant tstm mention late afternoon.
Will have slight chance of showers along and east of Hwy 17
during the morning, then mainly chance POPs of showers/isolated
tstms all zones in afternoon. Better chance of showers/storms
and marginal threat of severe will be Monday night with better
dynamics. Low level thicknesses increase to around 1390 meters
but increased cloud cover expected to keep max temps near 80
inland to mid-upper 70s Outer Banks.


As of 345 PM Sunday...A strong cold front will bring a good
threat of showers with a few thunderstorms Monday night through
Tuesday followed by another shot of seasonably cool air for mid
to late next week.

Monday night through Tuesday night...A deep upper trough and
strong cold front will move through the region this period
bringing periods of heavy rain and a marginal threat of severe
storms. Vorticity advection increases as models depict dampening
shortwave trough pivoting through the TN/Ohio valleys, and will
spur sfc cyclogenesis in the southern Appalachians acting to
increase dynamics and strengthening southerly flow on 40-50 kt
LLJ. Dewpoints will be quite high in the 60s and would be
sufficient for marginal instability, and the combination of
significant wind shear and marginal instability will spell a
high shear/low CAPE scenario for strong or severe storms. Any
heavy showers or isolated thunderstorms could produce strong
gusty winds due to momentum transfer to the sfc from strong
winds aloft.

There remains some uncertainty with the timing of the heavier
precip/stronger storms as 22/12z models are not in best
agreement but they have continued to trend a little faster with
onset Monday night. The GFS is on the faster side of guidance
bringing in heavier precip Monday evening while the NAM is on
the slower side delaying onset until early Tuesday morning. The
ECMWF and CMC are between these solutions. Due to the amplifying
nature of the upper trough digging into the eastern CONUS the
front will be slow to move across the region and expect descent
rain chances to continue through the day Tuesday, especially
east of highway 17, and continuing along the coast Tuesday night
into Wednesday morning.

Temps will be mild Monday night and Tuesday with strong
southerly flow ahead of the front. Lows Monday night expected
around 65-70 with highs Tuesday in the mid to perhaps upper 70s.
Much cooler Tuesday night as the front pushes offshore and
expect lows in the lower 50s inland to around 60 coast.

Wednesday through Friday....Continued drying and cooling
expected Wednesday as the front will have pushed well off the
coast by early morning. Have retained the small PoPs for
Wednesday though confined them to the extreme eastern areas
mainly the OBX as the deep upper low moves through E NC with
lingering deep layer moisture across the OBX. Dry WNW flow on
Thursday as upper low finally exits off the Mid Atlantic coast
and high pressure builds into the region. Temps will be much
cooler for the mid week period with Wednesday and Thursday both
in the mid 60s to near 70 for highs. High pressure slides
offshore Friday with return flow bringing gradually warming
temps with highs around 70s. Low temps fall back into the 40s
inland and low/mid 50s beaches for Thursday/Friday mornings.

Saturday and Sunday...The high moves offshore next weekend
with another highly amplified upper trough and surface cold
front approaching from the west. Models remain in poor agreement
with the timing and details with the system but there will
likely be another good shot of precip and perhaps a period of
strong storms sometime next weekend as there will be increasing
jet dynamics with a moisture feed from the tropics into the
region. Temps will likely be near to a little above normal.


Short Term /through 18Z Monday/...
As of 730 PM Sunday...High confidence of VFR conditions will
dominate most of the TAF period. An increase of high clouds will
stream through the area as low clouds increase along the coast.
Models are showing a mix signal with fog developing across ENC.
Guidance continues and now the RAP forecast sounding indicates
the best potential for fog development will be over NW sections
and therefore forecasted a TEMPO period of IFR at KPGV and KISO
08Z-12Z. Conditions will improve in the the morning as winds
increase from SE around 10 knots gusting up to 20 knot by the
afternoon. Showers/isolated thunderstorms chances increase in
the afternoon ahead of the approaching cold front.

Long Term /Monday night through Friday/...
As of 4 PM Sunday...Periods of MVFR/IFR ceilings and vsbys are
likely with fairly widespread showers and perhaps a few
thunderstorms Monday night through the day Tuesday. The
precipitation should move east of the TAF sites by Tuesday
evening with much drier air moving in behind a strong cold
front. VFR conditions should prevail Wednesday through Friday,
although some decent radiational cooling conditions could lead
to some fog, especially around KPGV and KEWN both Wednesday and
Thursday mornings.


Short Term /through Monday/...
As of 1025 PM Sunday...Current marine forecast in great shape.
The latest buoy observations are showing mostly easterly winds
5-10 knots north of Diamond Shoals and SE winds south. Seas 2 to
3 ft.

Pre Dis...High pressure extending over area from NE
will continue to move offshore tonight and Monday. NE-E winds
around 10 kt will become E-SE 10-15 KT overnight, and then SE-S
15-20 KT with gusts to 25 KT by late afternoon. Initiated SCA
for waters south of Oregon Inlet starting 5 PM Monday.

Seas will build with increasing winds late tonight and Monday,
with heights 4-6 feet expected outer southern and central waters
by late in the day.

Long Term /Monday night through Friday/...
As of 415 PM Sunday...A strong cold front approaches the region
Monday night and Tuesday, then pushes through the waters
Tuesday night. Southerly winds increase drastically Monday night
and Tuesday, peaking around 20-30 kt with some gale force gusts
possible. Seas build to 6-9 ft Monday night and 7-11 feet
Tuesday. Have initiated an SCA starting late Monday/Monday
evening for all waters except the inland rivers with this
package. The front pushes through the region Tuesday night
with winds becoming W/NW around 10-15 kt through Wednesday. Seas
gradually subside Tuesday night to around 4-6 ft Wednesday.
Gradients tighten some Wednesday night into Thursday and the
upper trough axis swings through and expect NW winds around
10-20 kt with seas continuing around 4-6 ft. By late Thursday
expect winds to diminish to below 15 kt with seas dropping below
SCA criteria. Light southerly winds around 5-10 kt expected
Friday with seas around 2-4 ft.


MARINE...Small Craft Advisory from 10 PM Monday to 10 PM EDT Tuesday
     for AMZ135.
     Small Craft Advisory from midnight Monday night to 6 PM EDT
     Tuesday for AMZ130-131.
     Small Craft Advisory from 5 PM Monday to 6 PM EDT Thursday for
     Small Craft Advisory from 5 PM Monday to 10 AM EDT Thursday
     for AMZ156.
     Small Craft Advisory from 8 PM Monday to noon EDT Thursday for
     Small Craft Advisory from 5 PM Monday to 10 AM EDT Wednesday
     for AMZ158.


MARINE...JBM/SK/BM is the U.S. government's official web portal to all federal, state and local government web resources and services.