-- Discussion containing changed information from previous version are highlighted. --
559
FXUS62 KMHX 200505
AFDMHX

Area Forecast Discussion
National Weather Service Newport/Morehead City NC
105 AM EDT Thu Jun 20 2024

.SYNOPSIS...
High pressure continues to extend across the Carolinas with
coastal troughing noted as well through Friday. This may bring
some showers to the region into the weekend. A steady increase
in heat and humidity is expected over the next several days with
"feels like" temperatures potentially reaching the triple
digits on Sunday. Next threat for appreciable rain comes early
next week with a frontal passage.

&&

.NEAR TERM /OVERNIGHT/...
-- Changed Discussion --
As of 915 PM Wed...No changes to previous thinking. Latest
surface analysis continues to show high pressure ridging west
from the Atlantic across the Mid- Atlantic tonight with a weak
coastal trough noted just off of the Carolina Coast. The
aforementioned coastal trough has resulted in some surface
convergence across our offshore waters and around portions of
the OBX resulting in some very isolated sprinkles. But, given
the isolated nature of this precip and the amount of dry air
across the region, this activity is not expected to strengthen,
or increase in coverage or intensity so will keep the forecast
precip free.

As we get into tonight, high pressure will remain anchored across
the Mid-Atlantic keeping things dry across ENC. However, with
continued weak E`rly flow low level moisture will continue to
increase resulting in a scattered to potentially broken deck of mid
and low level clouds across portions of ENC. This will once again
cap any potential fog threat. HREF probs for vis of less than 5
miles is less than 10% across ENC which re-enforces this thought.
Mild overnight temps return ranging from the low-mid 60s across
the inner coastal plain to upper 60s to low 70s along the OBX.
-- End Changed Discussion --

&&

.SHORT TERM /THURSDAY/...
As of 4 PM Wednesday... We continue to see onshore E`rly flow,
weak coastal troughing, and weak WAA across the area. Though
latest Hi-Res guidance has backed off precip chances across the
region as it looks like stubborn dry air will remain over much
of ENC. Even if we do see a stray shower or two from the
aforementioned coastal troughing amounts would be very light,
generally a trace to maybe a hundredth of an inch and given the
uncertainty with precip actually falling opted to keep ENC
precip free for Thurs. Otherwise, Thurs should be the last day
of near normal temperatures thanks to lower thicknesses in the
continued easterly low-mid level flow.

&&

.LONG TERM /TONIGHT THROUGH WEDNESDAY/...
As of 230 AM Wednesday...

 - Elevated fire weather concerns continue into this weekend

 - Building heat and humidity this weekend into early next week

 - Increased thunderstorm risk early next week

Synoptic Summary: Surface and upper level ridging are forecast to
remain in place through the end of the work week. Ridging then
begins to break down over the weekend and into next week as upper
level troughing develops from the Great Lakes into the Eastern
U.S.

Friday-Sunday: Medium range guidance continue to insist that the
upper level pattern will begin to change during this time. As upper
level ridging breaks down, and as the surface high shifts offshore,
a moistening return flow is forecast to develop. Within this flow,
low-level thicknesses will begin to increase as well. This will lead
to a steady increase in the heat and humidity, starting Friday,
and most likely peaking on Sunday. By Sunday, dewpoints in the
70 and highs in the 90s is expected to support "feels like"
temperatures rising into the 100-105 degree range. This has been
consistently supported by both deterministic and ensemble
guidance, and we`ll plan to begin messaging this impact in the
HWO and other public- facing products.

Despite increasing moisture, warm temps aloft will support a notable
cap through at least Saturday. This combined with limited forcing
should keep the risk of showers and thunderstorms at a minimum. Any
chance of showers should be confined to the daily seabreeze. On
Sunday, less of a cap is expected, and we should see a little more
activity on the seabreeze (but probably still isolated in coverage).

Lastly, a tightening pressure gradient within the developing lee-
trough will support increasing south to southwest winds by Sunday.
Ensemble guidance suggests dewpoints will mix out across the coastal
plain as the winds and mixing increase, and this seems reasonable
given the dry pattern of late, and very dry soils. With this in
mind, the overlap of lower RH and breezy conditions should support a
continued elevated fire weather risk.

Monday-Wednesday: Deterministic and ensemble guidance continue to
show a moderate to strong signal for deeper moisture reaching
Eastern NC within the continued southerly low-mid level flow. This
in tandem with the seabreeze, a glancing shortwave, and possibly a
cold front dropping into the area is expected to support an
increased thunderstorm risk, especially on Monday. The overlap of
moderate instability and modest deep layer shear could also support
a marginal severe thunderstorm risk.

Dewpoints are expected to peak during this time, with a subsequent
peak in humidity values. Afternoon highs are less certain, though,
due to the potential for increased convective activity. However,
given the boundary layer moisture in place, "feels like"
temperatures could make a run at 100+ where sufficient heating can
occur. Right now, Monday looks to carry the greatest risk of heat-
related impacts.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --
SHORT TERM /through Thursday/...
As of 1 AM Thursday...VFR conditions persist. Light easterly
winds will carry us through the night and continue to increase
our moisture. This will present another opportunity for low to
mid level stratus to develop across the area with a low but
non-zero threat of brief MVFR ceilings. Ceilings will lift in
the morning and make way for diurnal cu in the afternoon. A
better fog setup will be in place at the end of this TAF
period/beginning of the 12Z period given clear skies and
decoupling winds overnight.

LONG TERM /Thursday night through Monday/...
As of 230 AM Wednesday...

 - Sub VFR CIGs possible (40-60% chance) along the coast Thursday

 - Breezy southerly winds Sunday and Monday

 - Increased TSRA risk Monday

A moist easterly flow may continue to support isolated SHRA activity
along the coast on Thursday, along with SCT/BKN low CIGs. This
appears most likely along the coast, with less of a risk inland.
Drier air then works back in Friday into Saturday, with less of a
risk of SHRA or sub-VFR conditions. Breezy southerly winds are
likely Sunday into Monday (60-80% chance). Increasing moisture
within the southerly flow is also expected to lead to an increased
TSRA risk, especially by Monday.
-- End Changed Discussion --

&&

.MARINE...
SHORT TERM /through Thursday/...
As of 915 PM Wed...5 to 15 kt E`rly winds with occasional gusts
up around 20 kts and 3-5 ft seas currently persist across our
waters this evening. With high pressure remaining the dominant
feature across ENC through Thurs winds will continue to remain
E`rly at 5-15 kts with gusts to 20 kts at times. There will be
some weak coastal troughing noted through Thurs as well which
could kick off some very isolated showers, however confidence is
not high enough in this activity to include in the forecast.
The primary concern the next 24 hours is for elevated easterly
wind swell which the wave models bring to 6 ft tonight over the
extreme outer (>15 nm) central and southern waters. The NBM is
the most extensive and persistent with these seas while the NWPS
has the least coverage and shortest duration of the swell. Will
continue current SCA as seas have built to 6 ft at the 30 mile
and 5 ft at the Diamond Shoals buoys. The 5-6 ft seas should
persist along our Gulf Stream waters into Thurs afternoon before
subsiding to 3-5 ft late.

LONG TERM /Thursday night through Monday/... As of 230 AM
Wednesday...

 - Elevated wind and seas possible Sunday - Monday (40-60% chance)

 - Increased thunderstorm risk on Monday

Continued easterly flow is expected to continue to support seas of 4-
6 ft on Thursday. Seas then slowly lay down to 2-4 ft as we move
into the weekend thanks to a weakening of the easterly flow. Light
south winds of 5-15 kt Friday and Saturday increase to 15-25kt
Sunday into Monday, along with seas once again building to 4-6 ft. A
few showers will be possible on Thursday, and again on Monday. The
greatest risk of thunderstorms is expected Sunday night into
Monday.

&&

.FIRE WEATHER...
As of 4 PM Wed...While we will have a bit more moisture across the
region tomorrow with RH`s only getting down into the 40-45% range
(primarily away from the coast), given the continued dry airmass,
dry fuels across the area, and continued E`rly breezes these
conditions continue to remain noteworthy for any ongoing, or
planned, fires.

&&

.MHX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
NC...Beach Hazards Statement from 8 AM EDT this morning through
     this evening for NCZ195-196-199-203>205.
MARINE...Small Craft Advisory until 5 PM EDT this afternoon for AMZ152-
     154-156-158.
-- End Changed Discussion --

&&

$$
SYNOPSIS...MHX
NEAR TERM...JME/RCF
SHORT TERM...RCF
LONG TERM...RM
AVIATION...OJC/RM
MARINE...RM/JME/OJC
FIRE WEATHER...MHX