907
FXUS62 KMHX 260139
AFDMHX

Area Forecast Discussion
National Weather Service Newport/Morehead City NC
939 PM EDT Sat May 25 2024

.SYNOPSIS...
A surface trough will reside across the piedmont while a series
of upper level shortwaves will generate multiple rounds of
shower and thunderstorms into early next week. A stronger cold
front will move through early next week, becoming cooler and
drier across the area.

&&

.NEAR TERM /OVERNIGHT/...
As of 930 PM Sat... Once again made no significant changes to
the forecast on this update as everything is tracking relatively
well. Latest radar trends have shown a marked decrease in shower
and thunderstorm coverage across ENC as of this update and that
trend will continue over the next few hours. The fog threat for
tonight still seems rather uncertain especially given recent
trends across the NOBX where visibilities have increased
significantly since this afternoon. Guidance has backed off
general timing of a second surge of seafog settling in across
the NOBX with fog now coming into the area closer to 4-5AM but
given it still has fog settling in have left fog in the
forecast for now but note this may change especially if trends
continue to show a lack of fog in the coming updates. Areas of
radiational fog may also develop inland late tonight and and
early Sun morning, mainly along and west of Hwy 17 especially
across areas where it had rained this afternoon and evening.
Once again expecting lows in the mid to upper 60s across ENC.

&&

.SHORT TERM /SUNDAY/...
As of 3 PM Sat...Little change to the pattern Sunday with
nearly zonal flow aloft while weak low offshore continues to
move eastward. Boundary layer moistening beneath modestly steep
mid- level lapse rates should support MLCAPE climbing to 1-2000
J/kg during the afternoon. Main source of lift will be the
seabreeze, with isolated to widely sct showers and thunderstorms
possible. Deep layer shear of 20-30 kt plus moderate
instability appears supportive of a pulse severe mode capable of
wind and hail. The limiting factors will be weak lift and a
modest cap with warm temps aloft. Low level thickness values
support above normal temps, with highs near 90 inland and 80s
for the beaches. Sea fog threat could linger along the Outer
Banks beaches through mid day.

&&

.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
As of 200 AM Saturday...

 - Watching thunderstorm risk through Monday

 - Elevated heat risk Sunday and Monday/Memorial Day

 - Not as hot mid to late-week

Synoptic Summary: Multiple shortwaves embedded within zonal flow
aloft will traverse the Carolinas through Sunday night, with each
carrying at least a chance of showers and thunderstorms. On Monday,
a stronger wave will glance the area, sending a cold front southeast
through the area Monday night or Tuesday. Guidance differ on how
quickly that front will get through Tuesday, and how far off the
coast it gets. Eventually, a potent upper level shortwave will move
through mid-week, pushing the front well offshore. A cooler post-
frontal regime then settles in to close out the work week.

Monday/Memorial Day: Continued southerly low-level flow should
support dewpoints rising into the 70s beneath steep mid-level lapse
rates. Heating of the moist boundary layer in combination with the
steep lapse rates should support moderate to regionally strong
MLCAPE of 2000+ j/kg. Temps aloft will be warming as well, though,
which will lead to a seasonably strong capping inversion.
Synoptically, an upper level shortwave will lift NE from the Ohio
Valley into the northern Mid-Atlantic, with a glancing influence to
the south across the coastal Carolinas. The greatest chance of
thunderstorms should be focused just to our NW and N where the
greatest lift is expected. If storms manage to develop this far
south, the combination of moderate to strong instability, steep
lapse rates, and sufficient deep layer shear will be supportive of
severe thunderstorms. This will be a day to watch, especially given
the above-mentioned overlap of shear and instability, but
questionable forcing and a modest cap make confidence lower.
Thunderstorms aside, and barring more cloudcover than currently
forecast, Monday has the potential to see well above normal highs.
This combined with dewpoints in the 70s will support a "feels like"
temperature of 95-100 degrees, leading to an elevated heat risk.
While the heat risk is not forecast to reach high enough to warrant
heat headlines, it`s noteworthy coming on a busy holiday weekend,
with a lot of outdoor activities, etc. The risk will be highest for
those with extended time outdoors and/or those without a way to
sufficiently cool down.

Tuesday-Wednesday: Model guidance begin to differ during this time.
The main challenge is how quickly Monday`s front moves offshore, and
whether or not it stalls for a time. The slower guidance keeps a
risk of showers and thunderstorms potentially lasting all the way
into Wednesday, while the faster and further offshore guidance
paints a much drier picture. Blended guidance holds onto a chance of
precip Tuesday, but is dry on Wednesday. This seems reasonable for
now, but be aware that the potential exists for precip to last
longer than currently advertised. Temperatures will begin to "cool"
during this time, but how cool will depend on how quickly the front
moves through.

Thursday-Saturday: There remains a fairly solid signal in guidance
depicting a potent shortwave moving through the US East Coast,
sending a strong cold front through the coastal Carolinas Wednesday
night or Thursday. It`s expected that this will usher in a
noticeably "cooler" airmass for at least a couple of days, with
dewpoints falling back into the 50s, and lows bottoming out in the
50s and 60s. Highs are expected to be in the 70s to near 80. While
the airmass will be drying, this may not equate to a lack of
precipitation. The potential is there for a shortwave, or two, to
move through supporting at least a low-end risk for showers and
thunderstorms, especially towards next weekend.

&&

.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
SHORT TERM /through Sunday/...
As of 730 PM Sat... No significant changes in the aviation
forecast for tonight and into Sunday as the greatest forecast
challenge for this evening will be the fog/ceiling forecast.
Thunderstorm risk will slowly decreases after sunset.

Currently seeing IFR/LIFR ceilings and vis across the NOBX and
adjacent waters as seafog remains around the area with the
threat for this fog to continue to expand SEwards across
portions of the OBX and NE`rn zones tonight while VFR ceilings
remain elsewhere. With this in mind did keep VFR ceilings across
all TAF sites tonight with a SCT MVFR deck of clouds south and
east of Dare/Hyde/Tyrell Counties between 09-12Z. Even if areas
did see lower ceilings current thinking is just about
everywhere outside of the NOBX will return to VFR ceilings by
mid morning.

There remains a risk of fog overnight into early Sun morning.
Best fog chances likely along and west of Hwy 17 as well as over
the Outer Banks. Conditions will return to VFR by mid morning
Sun, with potential for another round of sct afternoon showers
and storms. While I kept the area in VFR conditions, by Sun
afternoon LCL`s look to hang around 3 kft so added in a SCT MVFR
deck in the afternoon as well to catch any potential diurnal Cu
development.

LONG TERM /Sunday night through Thursday/...
As of 200 AM Saturday...There will be daily risk of TSRA
through Tuesday, with accompanying sub-VFR conditions. Outside
of TSRA activity, mostly VFR conditions are anticipated. On
Monday, gusty southerly winds appear likely (60-80% chance)
ahead of an approaching cold front, especially Monday afternoon
into Monday evening. SHRA/TSRA risk may linger into Wednesday
before drier air works in by Thursday.

&&

.MARINE...
SHORT TERM /through Sunday/...
As of 3 PM Sat...Main concern across the waters through the
period is areas of dense sea fog. Marine Dense Fog Advisory
continues for the northern waters based on cams, with vsbys
still 1 nm or less from Duck down to Nags Head. Based on good
agreement in the guidance, went ahead and issued another marine
DFA beginning this evening for the northern sounds, eastern
Pamlico Sound and central waters, where expect vsbys to drop
back down to 1 mile of less. Vsbys expected to grad improve
through the day Sun as winds become more SE, though could again
linger a bit longer.

Latest obs show light and variable 5-10 kt with seas 1-3 ft.
Very pleasant conditions will continue across the waters through
the period. Flow becomes more S-SE tonight into Sunday with seas
around 2 ft.

LONG TERM /Sunday night through Thursday/...
As of 230 AM Saturday...

 - Approaching Small Craft conditions Monday/Monday night

 - Periods of thunderstorms through early next week

Several upper level waves will move through the ENC coastal waters
through early next week. Each wave will bring with it a chance of
showers and thunderstorms. A stronger wave, and associated cold
front, then moves through Monday/Monday night. Southerly winds will
increase to 15-20kt ahead of this front, and may approach 25kt for
some waters. Right now, though, the risk of widespread 25kt winds
appears low (<10% chance). Seas of 1-3 ft over the weekend will
increase to 3-4 ft Monday with the building winds. The highest seas
are expected south of Cape Hatteras.

&&

.MHX WATCHES/WARNINGS/ADVISORIES...
NC...None.
MARINE...Dense Fog Advisory until 10 AM EDT Sunday for AMZ131-135-150-
     152-230-231.

&&

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