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339
FXUS62 KMHX 210646
AFDMHX

Area Forecast Discussion
National Weather Service Newport/Morehead City NC
246 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 /TODAY/...
-- Changed Discussion --
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.
-- End Changed Discussion --

&&

.SHORT TERM /TONIGHT/...
-- Changed Discussion --
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.
-- End Changed Discussion --

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
As of 330 AM Friday...Ridging starts building in through the
weekend as a low spins up offshore to our northeast, gradually
shifting further offshore to our east. Slight chances of rain
Sunday-Sunday night (20%) but otherwise a dry forecast through
Tuesday. Seasonable temps through the period and generally dry
through Tuesday evening. Rain chances increase mid to late week
as ridging weakens and a low treks across the Ohio Valley and
Great Lakes region.

The Weekend:
Expanded the slight chance of showers (and thunderstorms during
peak heating) Sunday with synoptic models all keying in on 2
waves of potential rainfall.

First Sunday morning a weak front and associated isentropic lift
from a low developing near the Great Lakes moves through the
region. Ridging from a high to our E/SE will help shelter the
southern half of the CWA from rainfall, but have expanded the
slight chance PoP mentions for the northern half where ridging
is a bit weaker. This front fizzles out as it crosses our CWA.

The second wave looks to be Sunday afternoon/evening as a
boundary ahead of ridging building in from the north could
initiate showers over ENC. Introduced Schc PoPs with this
update, opting to not go higher as we have a lack of upper level
support.

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

Ridging and dry conditions continue through Tuesday evening.
Tuesday night ridging starts to weaken over ENC as a low
approaches from the midwest, pushing the high further northeast.
While a cold front from this low will be pushing through the
ohio and mississippi valley Tuesday, there is uncertainty on
when the front will reach us. If the ridge takes longer to move
out of here, the front could reach us as soon as Wednesday
morning. There is also a chance that the front doesn`t reach us
at all if ridge remains stubborn. Kept PoPs at Schc for now
Wednesday with so much uncertainty with the front. High
offshore helps channel moisture towards ENC mid to late week,
increasing PoPs to Chc/Schc Wednesday night onwards as we enter
a wetter pattern.

&&

.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
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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 345 AM Friday...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 400 AM Friday...SCA In Effect through 6Z Tuesday (and
will likely need to be extended further with future updates) for
coastal waters north of Ocracoke.

Sustained NE winds 10-15 kt Sunday, then 15-20 kt Monday before
dropping back down to 10-15 kt Tuesday. Winds have continued
trending down Sunday into Monday, forecasted to remain generally
below 25 kts. Waves greater than 6 ft from the low offshore
have warranted an SCA issuance for the coastal waters N of
Ocracoke (with other coastal waters also likely to reach SCA
criteria seas early next week given the current forecast), Seas
will be 2-7 ft Saturday, 2-6 ft Sunday, and 2-8 ft
Monday/Tuesday as gusty winds + the low offshore results 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...
-- Changed Discussion --
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.
-- End Changed Discussion --

&&

.MHX WATCHES/WARNINGS/ADVISORIES...
NC...Coastal Flood Advisory until 2 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.

&&

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