825
FXUS62 KMHX 212039
AFDMHX

Area Forecast Discussion
National Weather Service Newport/Morehead City NC
439 PM EDT Tue May 21 2024

.SYNOPSIS...
High pressure builds in from the north keeping much of the area
dry through Thursday before the next potential frontal system
moves through late week through the weekend and brings a return
to unsettled weather.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 400 PM Tuesday...

- Increased risk of widespread dense fog again tonight

High pressure continues to nose south along the Mid-Atlantic
Coast this afternoon, and will eventually shift over, or just
offshore, of the ENC coastline through tonight. Low clouds from
this morning have mostly mixed out, with the exception of the
Outer Banks, where the low-level inversion is holding strong
with the continued northeasterly onshore flow off the cooler
waters of the Atlantic. Those clouds will probably not
completely dissipated this afternoon, and I`ve held onto mostly
cloudy skies there for most of the afternoon. Elsewhere,
afternoon cumulus clouds will develop within the moistening
return flow off the warmer Atlantic waters south of Hatteras.

Within that moistening flow, dewpoints are forecast to rise
back into the 60s by this evening. Meanwhile, with high pressure
overhead and light winds, T/Td spreads will quickly decrease,
setting up what appears to be a solid signal for fog tonight.
Short-term guidance is showing a much stronger signal for fog
compared to this morning, with probabilities of dense fog as
high as 60-80%, especially across the coastal plain and OBX. The
previous forecast handled this potential nicely, so no changes
to the forecast or messaging are planned. Assuming confidence
remains high, a Dense Fog Advisory will mostly likely be needed.

&&

.SHORT TERM /WEDNESDAY/...
As of 100 PM Tuesday...

- Trending warmer, but still mostly dry, on Wednesday

Surface high pressure shifts further offshore on Wednesday,
with lee- troughing developing east of the Appalachians. This
will lead to a modest increase in southerly flow across the
coastal Carolinas. The increased southerly flow plus warming
thicknesses beneath ridging aloft will support high topping out
5-10 degrees higher than today. While instability will steadily
build, it appears there will be enough of a cap beneath the
ridge to keep the risk of afternoon convection very low. The one
exception is along the central OBX where a coastal trough
approaching from the east may support a few showers near, or
just offshore by the afternoon.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
As of 3 AM Tuesday...High pressure continues to build in from
the north through Thursday. A series of shortwaves will come
through the region Friday through the weekend, with a wetter and
more unsettled end the long term.

Wednesday night through Thursday...High pressure builds across
the Mid- Atlantic and Southeast. Expect dry conditions through
Thursday, along with steadily warming conditions. By Thu,
temps rise to near 90 and back above climo. In fact, some areas
may flirt with low 90 degree highs by Thu. Lows will be in the
60s.

Friday through Monday...High pressure shifts offshore to our
west and more active pattern kicks in with multiple shortwaves
impacting the region. Thundershowers possible with each of
these waves with a warm/humid airmass in place, thanks to the
high offshore. Rain chances ahead of the shortwave and frontal
system early Friday have trended a bit drier, so kept PoPs
generally at Schc, with highest values the further north you go.
After the front passes through, a series of shortwaves impact
ENC, one on Friday night through Saturday, and another Monday
into Monday night. Both of these shortwaves carry Chc PoPs with
them. Followed closer to climo, and kept highest thunder chances
in the afternoon and evening periods. At this point severe
weather threat appears to be low through the weekend.

&&

.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
SHORT TERM /through 18z Wednesday/...
As of 100 PM Tuesday...

- Increased risk of IFR/LIFR conditions tonight (due to BR/FG)

High pressure will shift over the area this evening, then
offshore by Wednesday morning. The developing return flow around
the high will lead to an increasing layer of shallow moisture
through tonight. As temp/dewpoint spreads decrease with light
winds tonight, there will be an increased risk of dense fog
developing. Short-term guidance is showing a much stronger
signal for FG tonight, with a more widespread coverage likely.
Probabilistic guidance is showing a 60-80% chance of LIFR/IFR
VIS in BR/FG tonight, and we`ll trend the TAFs more
pessimistically in this direction.

LONG TERM /Wednesday night through Sunday/...
As of 3 AM Tuesday...Pred VFR conditions are expected early
through mid week. Multiple rounds of showers and thunderstorms
Friday onwards could result in lower vis and ceilings.

&&

.MARINE...
SHORT TERM /through Wednesday/...
As of 400 PM Tuesday...

- Dense fog threat returns tonight into Wednesday morning

High pressure will continue to nose into the area through
tonight, then shift further away from the coast on Wednesday.
Light winds will allow seas to continue to lay down, with good
boating conditions for most waters during the daylight hours.
The exception will be the evening through morning hours, when
dense fog will impact much of the coastal waters. It`s likely
that another Marine Dense Fog Advisory will be needed to cover
this threat, so stay tuned for updates and later headlines.

LONG TERM /Wednesday night through Sunday/...
As of 3 AM Tuesday...High pressure will remain in control
through Thursday morning, resulting in good boating conditions.
As the high moves offshore through the day Thursday, SW winds
pick up, gusting near 20 kts Thursday afternoon/evening. Winds
come back down a tad Thursday night, but multiple chances of
showers and thunderstorms exist Friday through the weekend.

&&

.MHX WATCHES/WARNINGS/ADVISORIES...
NC...None.
MARINE...None.

&&

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