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822
FXUS62 KMHX 251858
AFDMHX

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

.SYNOPSIS...
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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.
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&&

.NEAR TERM /THROUGH TONIGHT/...
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As of 3 PM Sat...Latest analysis shows weak low pressure just
off the NC coast, troughing inland and shortwave pushing into
the Carolinas. Low level N/NW flow has kept the seabreeze pinned
along the coast early this afternoon. Widely scattered showers
and iso tstms beginning to blossom west and south of the
forecast area in response to shortwave energy and slowly
propagating seabreeze. Coverage will increase over the next few
hours, with best chances across the southern half of the area.
Latest mesoanalysis shows ML CAPE values 1-1500 J/kg, with bulk
shear 15-25 kt. Shear will continue to be the limiting factor,
likely just supporting threat for pulse type storms with a low
svr risk. However, any stronger storm that is able to develop
could produce gusty winds and small hail. Expect convection to
grad dissipate with loss of heating after sunset tonight.

Another forecast challenge through the overnight is the areas
of dense sea fog, which has been locked in portions of the
Northern Outer Banks all day. It appears to remain localized
this afternoon, mainly impacting the beaches from Duck down
towards Nags Head. However, guidance is in very good agreement
with sea fog expanding south and westward this evening and
overnight...which could impact areas adj to the northern sounds
as well as the Outer Banks. Locally dense fog will be possible,
and will continue to monitor. Areas of radiational fog may also
develop inland late tonight and and early Sun morning, mainly
along and west of Hwy 17.
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&&

.SHORT TERM /SUNDAY/...
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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.
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&&

.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
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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.
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&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
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SHORT TERM /through Sunday/...
As of 3 PM Sat...VFR conditions across the terminals this
afternoon with sct diurnal cu. Isolated to widely sct showers
and tstms expected to develop in the next few hours, all sites
could see a storm, with best chances at ISO and OAJ. Thunderstorm
risk will grad decrease after sunset. Increased risk of fog and
potentially low stratus 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.

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.
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&&

.MARINE...
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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.
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&&

.MHX WATCHES/WARNINGS/ADVISORIES...
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NC...None.
MARINE...Dense Fog Advisory from 8 PM this evening to 10 AM EDT Sunday
     for AMZ131-135-152-230-231.
     Dense Fog Advisory until 10 AM EDT Sunday for AMZ150.
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&&

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