-- Discussion containing changed information from previous version are highlighted. --
767
FXUS62 KMHX 211400
AFDMHX

Area Forecast Discussion
National Weather Service Newport/Morehead City NC
1000 AM EDT Sat Sep 21 2024

.SYNOPSIS...
High pressure will ridge southwards across the Carolinas through
this weekend. Next potential frontal system doesn`t near ENC
until at least mid next week.

&&

.NEAR TERM /REST OF TODAY/...
-- Changed Discussion --
As of 10 AM Saturday...

 - Patchy, dense fog has dissipated

 - Quiet weather this afternoon

Overall did not make any significant changes to the forecast as
everything is tracking well. The patchy dense fog that had
impacted the Hwy 17 corridor has since lifted into an area of
low stratus which continues to dissipate as of this update.
Expect partly cloudy skies across all areas within the next
hour or so given latest satellite trends.

High pressure at the surface, and ridging aloft, is expected to
support dry, and quiet, weather conditions today. Temperatures
this afternoon will be close to, or perhaps slightly below,
yesterday. The main impact today will be areas of dense fog this
morning, especially along the HWY 17 corridor. Webcams and
surface obs are mixed on how impactful the fog is, therefore I
opted to go with a SPS as opposed to a Dense Fog Advisory.
-- End Changed Discussion --

&&

.SHORT TERM /TONIGHT/...
As of 200 AM Saturday...

 - Late night showers and thunderstorms possible (10-30%
   chance)

A mid-level shortwave is forecast to drop southeast from the
Great Lakes into the Mid-Atlantic this evening and tonight. At
the surface, high pressure is forecast to shift offshore, with a
weak return flow developing across ENC. The weak nature of the
return flow doesn`t bode well for significant low-level moisture
advection into the area. However, ahead of the mid-level wave,
increasing southwesterly flow aloft may allow sufficient
moisture advection in the 850-700mb layer. Short-term guidance
continues to show a solid signal for convection to develop
upstream to our NW later today, propagating SE with time as the
mid-level wave drops SE. Guidance is in pretty good agreement
showing some of this convection reaching central/eastern NC
after midnight tonight. Despite poor low-level moisture quality,
there may be enough low-mid level moistening to support an area
of modest elevated instability across parts of ENC. In light of
this, it seems prudent to keep at least a low-end chance of
showers and thunderstorms in the forecast late tonight,
especially across the coastal plain.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
As of 330 AM Saturday...A slight chance of showers Sunday, then
ridging starts building in from the north as a low spins up
offshore to our northeast, gradually shifting further offshore
to our east. Seasonable temps through the period and dry Monday-
Tuesday evening. Rain chances increase mid to late week as
ridging could weaken and a low treks across the Ohio Valley and
Great Lakes region.

Sunday:
Sunday morning a weak disturbance will be moving through the
region, resulting in slight chances of rain. As this disturbance
starts moving offshore, Sunday afternoon/evening a boundary
ahead of ridging building in from the north could initiate
showers over ENC as it sweeps down. continued Schc PoPs with
this update, opting to not go higher as we have a lack of upper
level support. Hi-res guidance is indicating showers to be
isolated to scattered in nature. Kept Tstorms out of the
forecast Sunday, as upper level subsidence keeps the mid levels
very dry, and it will be difficult for updrafts to punch through
this dry layer with CAPEs of only 500-1000 J/kg.

Monday-Tuesday:
Low offshore could produce high swell impacting OBX beaches
Monday-Tuesday. See TIDES/COASTAL FLOODING section for more
information.

High pressure centered over Maine and the Canadian Maritimes
has a ridge extending south over much of the east coast, keeping
us dry Monday and Tuesday. Seasonable temps with highs in the
low 80s inland, upper 70s to near 80 for beaches.

Wednesday-Friday:
Uncertainty increases a lot towards the middle and end of next
week, as multiple synoptic features will be at play and slight
deviations result in large changes with the forecast. While
ridging continues to spread over ENC from the north Wednesday, a
low pressure system forecasted to be over the Great Lakes will
have a cold front trailing from it extending down to the Gulf
coast. This cold front could stall to our west due to the
ridging over us, or the ridge weakens and gives way to the low,
or the front sweeps north of us around the high. In addition to
the parent low over the Great Lakes and ridge overhead, we will
be keeping an eye on a tropical system that could initiate in
the Gulf Coast next week. It is too soon to determine what
impacts, if any, we receive in ENC should this cyclone form. Due
to all this uncertainty, I opted to keep PoPs at Chc/Schc for
now through the remainder of the long term as a higher moisture
advection regime is more supportive of rain at the end of the
period.

&&

.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM /through 06z Sunday/...
As of 715 AM Saturday...

 - LIFR/IFR conditions last for another 1-2 hours this morning

 - TSRA possible late tonight (10-20% chance)

Low CIGs and VIS have out-performed expectations this morning,
with a fairly widespread area of LIFR/IFR conditions ongoing
across the western half of eastern NC (due to BR/FG). I expect
low CIGs and VIS to mix out by 13z, with VFR conditions
prevailing for the rest of the day. Later today, SHRA and TSRA
are expected to develop well to the NW of ENC, across central
VA. This activity is then forecast to progress SE into parts of
NC by this evening or late tonight. The activity is expected to
be on a weakening trend, but could impact portions of ENC after
06z tonight. Confidence is low regarding whether or not this
activity will make it this far south and east, so for now I`ve
opted to keep SHRA and TSRA out of the TAFs for now. Despite
decent low-level moisture tonight, the risk of BR/FG appears
lower than this morning thanks to increased mid/high clouds
moving into the area.

LONG TERM /Sunday through Wednesday/...
As of 4 AM Saturday...Pred VFR conditions expected through the
long term.

&&

.MARINE...
SHORT TERM /Through tonight/...
As of 715 AM Saturday...

 - Elevated seas continue across the coastal waters

 - Areas of dense fog this AM (mainly impacting the Neuse and
   Pamlico Rivers)

 - Good boating conditions for inland rivers and sounds by this
   afternoon

Satellite and webcams reveal an area of dense fog impacting
portions of the Neuse and Pamlico Rivers early this morning.
While short- lived, I decided to put out a short Marine Dense
Fog Advisory, especially being that it is a weekend with
potentially more boating activity.

Otherwise, there will be enough of a gradient to keep
northeasterly winds of 10-15kt going through the morning hours
today. By this afternoon, though, high pressure building in
should allow winds to lay down to 5-15kt. Winds will then be
east or southeast at 5-10kt this evening and tonight. For inland
rivers and sounds, this will lead to good boating conditions,
especially later today into this evening. For the coastal
waters, seas will continue to remain elevated through tonight
thanks to a continued northeasterly swell from low pressure
south of New England. Seas of 4-6 ft will be common north of
Ocracoke Inlet. South of there, seas of 3-5 ft are expected
through tonight. While seas may fluctuate some, there continues
to be sufficient evidence in support of keeping the SCA going
through tonight, and into the remainder of the weekend. In light
of this, no changes are planned for the ongoing SCA for the
central and northern coastal waters.

LONG TERM /Sunday through Wednesday/...
As of 415 AM Saturday...SCA In Effect through 6Z Tuesday for
coastal waters north of Ocracoke.

Sustained variable winds around 10 kt Sunday with ridging
building in, then around 15 kt Monday before dropping back down
to 5-10 kt and veering to become more easterly Tuesday and
Wednesday. SCA in effect for waters north of Ocracoke Inlet as
waves greater than or equal to 6 ft are expected from the low
offshore through early next week. Seas will be 2-6 ft Sunday,
and 2-7 ft Monday/Tuesday before dropping down to 2-6 ft
Wednesday the low offshore and somewhat gusty winds result in
higher swell. Waters off Crystal Coast and coastal Onslow will
be a bit protected from the more easterly swell courtesy of Cape
Lookout, and will be on the lower end of these wave height
ranges. OBX (particularly north of Hatteras) and the Gulf Stream
will not be protected and will see the higher values in the
ranges above.

&&

.TIDES/COASTAL FLOODING...
As of 245 AM Saturday...Coastal flooding will continue to be a
threat given the higher than normal astronomical tide cycle into
early next week during high tide each day. Coastal Flood
Advisories remain in effect for all oceanside coastal areas into
Monday morning`s high tide. Increased swell from a low offshore
may bring minor overwash concerns early next week for the OBX
north of Cape Hatteras, although recent guidance has backed off
some on the strength of this offshore low, which may lessen the
risk of coastal impacts.

&&

.MHX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
NC...Coastal Flood Advisory until 4 PM EDT Monday for NCZ195-196-
     199-203>205.
     Beach Hazards Statement until 8 PM EDT this evening for NCZ203-
     205.
MARINE...Dense Fog Advisory until 10 AM EDT this morning for AMZ136-137.
     Small Craft Advisory until 2 AM EDT Tuesday for AMZ150-152-154.
-- End Changed Discussion --

&&

$$
SYNOPSIS...MHX
NEAR TERM...RM/RCF
SHORT TERM...RM
LONG TERM...RJ
AVIATION...RM/RJ
MARINE...RM/RJ
TIDES/COASTAL FLOODING...MHX