-- Discussion containing changed information from previous version are highlighted. --
126
FXUS62 KMHX 210842
AFDMHX

Area Forecast Discussion
National Weather Service Newport/Morehead City NC
442 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 /UNTIL 6 PM THIS EVENING/...
As of 200 AM Saturday...

 - Quiet weather expected today

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.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
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/...
-- Changed Discussion --
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 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.
-- End Changed Discussion --

&&

.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
SHORT TERM /through 06z Sunday/...
As of 130 AM Saturday...

 - IFR/MVFR conditions possible overnight (40-60% chance)

The main forecast challenge overnight will be the potential for
MIFG/BR/FG. Short-term model guidance and satellite imagery
reveal a layer of dry air spreading SW across Eastern NC at this
time, which should help to keep the depth of low-level moisture
shallow. Synoptically, the pattern is favorable for the
development of FG, but conditions don`t currently appear
favorable for a deeper, more impactful, layer of FG. We`ll keep
a close eye on this through the night and amend the TAFs as
needed. For now, I stuck close to the previous TAFs,
highlighting a window of IFR/MVFR VIS in the 08z-12z timeframe.
On Saturday, high pressure will remain overhead with light winds
and VFR conditions.

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

&&

.MARINE...
-- Changed Discussion --
SHORT TERM /Through tonight/...
As of 200 AM Saturday...

 - Elevated seas continue across the coastal waters

 - Good boating conditions for inland rivers and sounds today

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.
-- End Changed Discussion --

&&

.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 from 8 AM EDT this morning through
     this evening for NCZ203-205.
MARINE...Small Craft Advisory until 2 AM EDT Tuesday for AMZ150-152-154.
-- End Changed Discussion --

&&

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