022
FXUS62 KMHX 062039
AFDMHX

Area Forecast Discussion
National Weather Service Newport/Morehead City NC
439 PM EDT Mon May 6 2024

.SYNOPSIS...
High pressure will rebuild offshore while weak troughing
continues across the Eastern Seaboard for the next few days,
but warm moist southerly flow will lead to unsettled conditions.
Drier but hotter conditions briefly expected Wednesday, before
an approaching strong frontal system brings unsettled weather
back to the area Thursday and Friday and potentially into the
beginning of next weekend.

&&

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

A cluster of thunderstorms over SE NC is moving northeast
towards the coastal plain of ENC. Meanwhile, isolated convection
is ongoing along the inland-advancing seabreeze (which
currently stretches from Goldsboro to Greenville). Over the next
few hours, I expect the SE NC cluster of thunderstorms to
continue to march NE, with a path closely tied to the advancing
seabreeze, where the airmass hasn`t yet been worked over. Cloud
tops have been warming with the SE NC convection, but the
downstream airmass is modestly unstable (MLCAPE around
1000j/kg), and there still appears to be room for some
intensification before the boundary layer begins to stabilize.
Along the seabreeze, convection has become more discrete, and
deeper, compared to earlier in the day, and I expect this trend
to continue for a few more hours.

South of the seabreeze, the airmass has been worked over and
slightly stabilized, and it`s unclear whether there will be any
renewed convective risk as the SE NC convection propagates ENE.
Breaks in the clouds have allowed temps to warm back into the
low 80s, so the risk for additional convection definitely isn`t
zero.

Despite decent instability, deep layer shear is very weak (only
10- 20kt), which will limit the potential for better storm
organization. Because of this, I expect the risk of severe
weather to remain LOW (10-20%) across the area at large through
this evening. That said, where taller, more sustained storms can
develop, the environment will be supportive of 40-60 mph wind
gusts and pea size hail.

While convection should tend to be heavily diurnally-driven,
there will be a couple of weak mid-level shortwaves that will
traverse the region through tonight, so I`ve opted to keep a
low-end mention of showers and thunderstorms going through the
night.

&&

.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
As of 400 PM Monday...

Tuesday has the look of a conditional severe weather day across
Eastern NC, with less coverage than today, but with a more
favorable environment.

Convection may be ongoing right along, or just off, the coast
in the morning associated with a weak mid-level wave moving
through. The wave doesn`t look particularly strong, but even so,
I expect there to be at least a brief period of subsidence in
its wake. Additionally, mid/upper level ridging will be
approaching from the west, adding to the potential for
subsidence. At minimum, I expect this to lead to a reduced risk
of thunderstorms compared to today.

With that in mind, though, and assuming full clearing during
the afternoon, strong heating of a moist boundary layer will
support MLCAPE climbing as high as 1000-1500 j/kg. Meanwhile,
mid/upper level northwesterly flow aloft atop a southerly low-
level flow will lead to an increase in deep layer shear (on the
order of 25-35kt). At face value, the environment on Tuesday is
expected to be more supportive of severe weather than today`s
environment. However, modest subsidence plus questionable low-
level forcing calls into question whether or not convection can
initiate in the afternoon. It appears that the seabreeze will be
the primary focus for convective initiation. Based on all of
the above, I expect a lower coverage of thunderstorms compared
to today, but if/where thunderstorms develop, there will be an
increased risk of severe weather compared to today. Also, it may
tend to be one of those days where convection develops later
than the typical early to mid-afternoon timeframe.

Regarding potential hazards, the environment will support
damaging winds and large hail with any sustained updraft. Mid-
level lapse rates aren`t forecast to be particularly steep, but
northwesterly flow aloft will increase the risk of rotating
updrafts, subsequently increasing the potential for hail
development. In this pattern, I expect LCLs to be a bit higher
(closer to 1000m), but the NW flow will provide some added
turning down low, and a tornado cannot be ruled out.

With the low-level flow taking on more of a westerly component
with time, low-level thicknesses will get a boost, and I expect
temps to respond by peaking higher than today (barring more
cloudcover than forecast).

Any convection that develops should weaken by late evening as
the boundary layer stabilizes, and as low-level forcing weakens.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
As 345 AM Mon...Unsettled weather will continue through midweek
as a weak trough lingers over the East Coast and warm moist
southerly flow develops. Wednesday may be the driest day of the
week with only isolated to widely scattered showers and
thunderstorms expected. However this lack of precipitation will
be accompanied by an increase in heat and humidity. An
approaching strong frontal system will then impact the area
Thursday into Friday once again bringing unsettled weather back
to the area. More benign weather possible over the weekend.

Wednesday...A more zonal upper level pattern briefly emerges
across the Mid-Atlantic as a weak impulse treks across the zonal
flow. At the surface SW`rly flow and increasing low level
thicknesses will result in hot and humid conditions with
afternoon highs reaching the upper 80s to low 90s inland, and
low to mid 80s along the coast. There is a chance for some
isolated shower and thunderstorm activity to occur especially
along any sea/sound breeze Wed afternoon as strong instability
will once again be in place though with weaker shear and forcing
compared to Tuesday current thinking is that storms won`t be
very organized in nature. This could change and bears monitoring
in the coming days but given latest thinking Wed still looks to
be the driest day out of the week so far.

Thursday through Sunday...Weak upper level troughing will again
redevelop overhead Thursday with a large trough looming across
the Great Lakes. This will bring a more conducive environment
for afternoon/evening shower and thunderstorm development with
hot and humid conditions expected again. Latest trends have sped
up an incoming cold front with the frontal passage now forecast
to occur Thurs night into Fri morning. As a result greatest
thunderstorm and severe threat is now likely on Thurs afternoon
and evening with a diminishing threat on Friday. With this
change in mind, did increase PoP`s to likely on Thurs afternoon
and lowered PoP`s on Friday to SChc to Chc.

Otherwise as noted above, strong instability (SBCAPE values
>1500 J/kg), ample 0-6 km shear (35-45 kts), and steep mid level
lapse rates (6.5-7.5 C/Km) will likely result in a more
widespread strong to severe thunderstorm threat Thurs afternoon
and evening.

Though a robust shortwave trough will then swing southward into the
area on Friday, with the quicker cold frontal passage precip on
Friday is now forecast to primarily remain rain with only an
isolated thunder threat as instability will have been shunted
well offshore.

The front will push through the area by Friday morning with mostly
dry conditions expected by Saturday and Sunday. A more seasonable
airmass will move in behind the front with highs near to just below
normal.

&&

.AVIATION /21Z MONDAY THROUGH SATURDAY/...
SHORT TERM /through 18z Tuesday/...
As of 100 PM Monday...

KEY MESSAGES

- Increased TSRA risk through tonight

- Occasional sub-VFR VIS/CIGs through tonight

FORECAST DETAILS

It appears that the developing seabreeze is on the move this
afternoon, and currently stretches from OAJ to EWN to FFA. SCT
SHRA and a few TSRA have been ongoing since this morning, and
this risk will steadily increase through the afternoon as the
seabreeze works inland. Additionally, a weak upper level wave
will move out of central NC and through Eastern NC later today
and tonight, offering increased lift for TSRA development. It`s
expected that this will translate to an increased risk of TSRA
from ISO to PGV by mid to late afternoon. SHRA and TSRA may then
attempt to move back towards this coast this evening and
tonight as the above-mentioned wave moves through, but
confidence in TSRA lowers after 00z this evening. For now, then,
I`ll continue to focus the SHRA and TSRA risk between now and
00z.

Like this morning, another round of low stratus is possible
(30-50% chance) in the wake of the TSRA activity. However, the
weather pattern tonight isn`t quite the same as last night, and
confidence is too low to include a sub-VFR CIG for tonight. SHRA
and TSRA may be ongoing early Tuesday morning, followed by a
brief lull mid to late-morning.

LONG TERM /Tuesday night through Saturday/...
As of 330 AM Mon...VFR conditions are expected for the most
part through mid-week outside of any shower or thunderstorm each
aftn/evening that impacts the area. Another round of sub VFR
conditions will be possible Thu afternoon and evening as a cold
front moves across the region bringing more widespread rain and
thunderstorm activity with VFR conditions likely returning at
some point on Fri.

&&

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

A background southwesterly flow of 15-25kt will continue over
the next couple of days, with a daily boost each afternoon and
evening with the strengthening thermal gradient. The gradient
will be stronger on Tuesday compared to today, and because of
this, I expect winds to bump up against 25kt for several hours.
The frequency and duration will be close to SCA criteria, but I
feel like it will be more of an occasional gusts to 25kt
scenario, so for now I`ve opted to go headline-free through
Tuesday night. We`ll continue to evaluate this potential in
later forecasts, though. In a similar fashion, seas should peak
a bit higher on Tuesday compared to today, but generally be in
the 3-5 ft range.

The risk of thunderstorms may increase later this evening and
through tonight as a couple of upper level waves move through.
On Tuesday, the risk of thunderstorms looks to be focused in the
morning hours, with a lessening risk through the day.

LONG TERM /Wednesday through Saturday/...
As of 345 AM Mon... An active weather pattern will lead to
deteriorating boating conditions through midweek. Otherwise
15-20 kt SW`rly winds will continue across all our waters with
ocnl gusts to 25 kts along the Gulf Stream waters on Wed. As a
cold front approaches on Thursday SW`rly winds increase further
closer to 15-25 kts with gusts up to 25-30 kts at times
promoting SCA conditions across our waters on Thurs with winds
potentially easing and becoming more westerly by the end of the
week. Seas will increase to 5-7 ft Thursday in response to
strengthening winds

&&

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

&&

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