Area Forecast Discussion
Issued by NWS Newport/Morehead, NC

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988
FXUS62 KMHX 221805
AFDMHX

Area Forecast Discussion
National Weather Service Newport/Morehead City NC
105 PM EST Sun Jan 22 2017

.SYNOPSIS...
A warm front will be draped across Eastern NC today and tonight.
A strong area of low pressure and frontal system will impact
the area tonight bringing a chance for severe thunderstorms. The
low will traverse the area on Monday and be replaced by high
pressure Tuesday into Wednesday. A cold front with limited
moisture will move through the area Thursday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
As of 1015 AM Sun...Complicated forecast through tonight but
the bottom line is that there is the potential for severe
thunderstorms with damaging winds and isolated tornadoes late
today and tonight with the greatest risk expected this evening.
SPC has nudged the Enhanced Outlook northward into Duplin and
Onslow counties with the remainder of eastern NC in a Slight
Risk area. Due to this risk WFO MHX will be conducting a special
21Z sounding to better assess this HSLC risk.

Complicating the forecast for NC is current area of showers and
widespread cloudiness across the area which will stabilize the
atmosphere. Looks like a weak area of low pressure is trying to
form along a subtle warm front like feature located within a
broad region of surface CAD. The models push the initial area of
showers off the Outer Banks around 17Z with the low level flow
becoming divergent and veering to the east. This coincides with
a model lull in precipitation 17Z-21Z when little to no
precipitation is expected to occur and have dropped PoPs from
likely to slight chance during this period. Coastal webcams
continue to indicate dense sea fog over portions of the northern
waters so have extended the MWS there until 18Z.

Late today it appears that at the surface a warm front will be
developing across southern portions of central and eastern NC.
While winds veer at the surface, aloft, backing flow will lead
to warm advection and increasing lift and expect precipitation
to develop rapidly 21Z-1Z with widespread showers and scattered
thunderstorms expected across the area. As the upper low
migrates toward eastern NC this evening, the kinematic
environment really improves as shear values rapidly increase
during this time with the 0-3/0-6km bulk shear and SRH values
become extreme, however instability appears to be limited with
MU CAPES only 250-500 J/kg but LI`s decrease to -2/-5 so will
have to monitor these trends very closely today as the more
unstable it becomes the more widespread the event will be. The
model SIG TOR and UH forecasts indicate that the best tornado
risk would be along the immediate coast from the Crystal Coast
to the Outer Banks south of Oregon Inlet this evening. This
could change though depending on how much instability develops
across our initially stable area.

Widespread low clouds, and moist soils from this mornings
showers will act to limit high temperatures today with max temps
ranging from the low/mid 60s northern area where low clouds are
expected to be most persistent to the upper 60s/lower 70s
southern areas where southerly flow flow is expected.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/...
As of 330 AM Sun...Again, the best threat for severe is
expected this evening as low pressure tracks through west
central North Carolina. Very good kinematics in place with
strong diffluence aloft, strengthening swrly LLJ, and backed sfc
flow producing large hodographs. Am quite concerned for a
tornado or two given the extreme low level speed/directional
shear in place, though this shear can only be realized if
discrete cells can become sfc based. High res NSSL WRF/NCAR Ens
convective allowing models indicate the threat being confined to
the immediate coast (Downeast Carteret through the OBX zones),
given interior zones remaining in east to northeast flow as the
warm front to the north will be in place across E NC following
earlier precip. ECMWF brings some sfc based capes inland a bit
more due to its stronger southerly flow, and would then see
better chance for severe across the interior zones. Regardless,
impressive dynamics ahead and along the approaching cold front
to the west along with warmer air surging in off the ocean may
offset the "lower" instability, with this system a prime example
of a high shear/low cape severe weather event. With these
impressive wind fields both damaging winds and isolated
tornadoes will be the main threats. All models are in good
agreement with the precipitation moving offshore late tonight.
Precipitation amounts could exceed an inch in many locations but
significant flooding is not expected at this time due to the
fast moving nature of the convection.

&&

.LONG TERM /MONDAY THROUGH SUNDAY/...
As of 3 am Sun...Latest run of GFS and ECMWF in good agreement
and used a blend. Deep surface/upper low swings across the
Carolinas Monday. Adjusted PoPs with just a low chance across
the southwest counties in the morning. In the afternoon went
with likely PoPs north and east with chance elsewhere. High
pressure will pass to the south Wednesday. A weak cold front
will pass through Thursday morning. Forecast soundings show best
available moisture confined to below 800 mb. Made no change to
current 30% PoP. The fast movement of the front will keep rain
amounts to only a hundredth or two of an inch. Dry weather
Friday and Saturday. Deep westerly flow across the region with
upper trof over much of the eastern US and a surface ridge to
the south and west.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
Short Term /Through Monday/...
As of 1 PM Sun...Generally poor flying conditions expected for
the terminals through Monday morning. Latest obs show widespread
IFR to LIFR ceilings, which are likely to persist through
tonight. Strong to severe thunderstorms will be possible this
evening and the first part of tonight, with best chances between
01-07z. Some storms could have damaging winds or an isolated
tornado. IFR and lower ceilings could persist through most of
the overnight hours, though EWN may have the best chance of
improving to MVFR at times. Expect conditions to improve to VFR
Monday morning, then could see ceilings lower back to MVFR
Monday afternoon with scattered showers.

Long Term /Monday night through Friday/...
As of 3 am Sun...Next chance of showers is Thursday, but again,
amounts will be very light so MVFR conditions expected. Dry for
the remainder of the time. Surface winds will be from the SW
10-20 knots Monday, NW 15-20 knots Tuesday, SW 10-15 knots
Wednesday and W 10-15 knots Thursday.

&&

.MARINE...
Short Term /Through Tonight/...
As of 1015 AM Sun...Winds currently W/SW 10 to 20 kt most areas
with some 15 to 25 kt over the outer southern/central waters
with seas 4 to 6 ft. Seas will build tonight to 8-11 feet just
ahead of an approaching fast moving cold front. A few hours of
gales certainly possible for the southern/central waters though
will be short lived so will not issue any gale headlines at this
time. The higher seas will arrive across the northern waters
late tonight and have initiated SCA for Oregon INlet to
Currituck beach light starting around 06Z.

Long Term /Mon through Thu/
As of 3 am Sun...Flow will be west to southwest through the long
term period. Poor boating conditions on the coastal waters for
much of the time. Deep surface/upper low moves northeast across
the region on Monday. On the coastal waters 15-25 knots expected
with seas 5-9 feet. Seas north of Oregon Inlet will subside
below 6 feet Wednesday and Thursday, but will Small Craft seas
will continue into Thursday for the remainder of the coastal
waters. Across the sounds and rivers sub-SCA conditions
forecast, with winds generally 5-15 knots. Only exception is on
the Pamlico Sound Monday night and Tuesday with 15-20 knots
forecast.

&&

.MHX WATCHES/WARNINGS/ADVISORIES...
NC...None.
MARINE...Small Craft Advisory until 3 AM EST Wednesday for AMZ152-154.
     Small Craft Advisory until 10 PM EST Tuesday for AMZ156-158.
     Small Craft Advisory from 1 AM Monday to 10 PM EST Tuesday for
     AMZ150.

&&

$$
SYNOPSIS...TL
NEAR TERM...JME/TL
SHORT TERM...TL
LONG TERM...HSA
AVIATION...CQD/HSA
MARINE...JME/HSA/TL



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