155
FXUS62 KMHX 061830
AFDMHX

Area Forecast Discussion
National Weather Service Newport/Morehead City NC
230 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 145 PM Monday...

Visible satellite imagery this afternoon shows the seabreeze
making steady progress inland, and is being quickened by the
background southerly low-level flow, as well as convective
outflow. As of this writing, it is just now approaching areas
from Kinston to Greenville. Showers and weak thunderstorms
continue to develop along the advancing seabreeze, but weaker
convergence and weak deep layer shear appear to be preventing
deeper, more sustained convection. However, slow storm motions
and PWATs around 1.50" are supporting heavy rainfall rates.
Because of the limited residence time over any one area, the
threat of flooding with the seabreeze convection looks low over
the next few hours.

Back to the SW, there appears to be a weak upper level
shortwave progressing slowly ENE through central SC/NC.
Convection associated with this wave has recently blossomed east
of the greater Charlotte metro. This convection is expected to
progress NE through the afternoon and early evening, and will
eventually interact with the inland-advancing seabreeze. This
will lead to an area of enhanced convergence, and is where I
expect the greatest risk of convection to be focused through
early this evening. In this area, MLCAPE of 500-1000j/kg is
forecast, with deep layer shear of 20-25kt. This overlap of
shear and instability is not overly supportive of severe
weather. However, the subtle bump in shear associated with the
above- mentioned shortwave may support a low-end risk of
gusty/damaging winds focused from Duplin County to Martin
County.

As the shortwave pushes through, convection may attempt to work
back towards the coast. However, the airmass to the east may be
more worked over, and it`s unclear if convection will survive
east of the coastal plain. There will be a modest increase in
forcing with the shortwave, which could help support a continued
risk beyond when we might normally expect convection to
decrease. With time, the risk of convection is expected to shift
offshore through the night. Like last night, an area of low
stratus may develop in the wake of the convective activity, but
the risk of fog appears low (10-30% chance).

&&

.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
As of 145 PM Monday...

Tuesday has the look of a conditional severe weather day across
Eastern NC.

Convection may be ongoing right along, or just off, the coast
in the morning associated with a weak mid/upper 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. With that in mind, 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 mid-afternoon CI time. 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,
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 SUNDAY/...
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 /19Z MONDAY THROUGH SATURDAY/...
SHORT TERM /through Tuesday Morning/...
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 /Monday night through Thursday/...
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 with the highest threat for
thunderstorm activity occuring on Tue. 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 Tonight/...
As of 730 AM Mon...Outside of convection decent boating
conditions are expected through tonight. Winds will be S/SSW at
10-15 kts through this afternoon, and then increase in response
to the building thermal gradient to become SW 15-20 kts tonight
through early tomorrow morning. Seas will be 2-4 ft today, and
increase to 3-5 ft early tomorrow morning.

LONG TERM /Monday night through Thursday/...
As of 345 AM Mon... An active weather pattern will lead to
deteriorating boating conditions through midweek. We start the
period off with 15-20 kt SW`rly winds and 3-5 ft seas across our
waters. Given the strong thermal gradient we may briefly flirt
with SCA conditions across our coastal waters Tue afternoon and
evening as ocnl gusts up to 25 kts will not be out of the
question. However confidence is not high enough to issue SCA`s
just yet and will let the day shift take another look to see how
things have trended. 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...SGK/RCF