575
FXUS62 KMHX 220827
AFDMHX

Area Forecast Discussion
National Weather Service Newport/Morehead City NC
427 AM EDT Sat Jun 22 2024

.SYNOPSIS...
High pressure shifts offshore today, with troughing developing
in the lee of the Appalachians. A cold front will move through
the area Monday into Tuesday, with another front affecting the
region on Thursday into Friday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
As of 200 AM Saturday...

 - Increasing heat and humidity today

Early this morning, satellite imagery very nicely depicts a
weak area of low pressure moving ashore just north of
Jacksonville, FL. North of that low, a broad area of deep,
quality moisture has expanded inland from the Atlantic into
coastal areas of the Southeast U.S. Based on satellite imagery,
the northern extent of that moisture shield reaches into
southern sections of ENC. Daytime heating of this moist airmass
appears supportive of "airmass" showers, but a lack of
appreciable forcing should tend to keep the coverage isolated,
and should help keep the risk of deeper convection low. Guidance
suggests the area of deeper moisture won`t shift much today,
which suggests the greatest chance of showers will be along the
coast from Hatteras south through the Crystal Coast, and for our
southwestern coastal plain counties (Duplin and Onslow
Counties).

The bigger story today will be the start of an extended period
of hot and humid weather. While it is summer in ENC, this period
of heat and humidity comes on the heels of several days of less
humid, and not as hot, conditions. There`s still some residual
dry air just above the surface, so any mixing today may tend to
keep dewpoints in the upper 60s for most of the coastal plain.
While it will be hot, dewpoints in the 60s would tend to keep
heat indices around 100 degrees. If less mixing occurs,
dewpoints would hold in the 70s, and heat indices could top out
as high as 105 degrees. Because of the marginal nature of the
heat indices, the plan for now is to hold off on any heat
headlines.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
As of 200 AM Saturday...

 - Patchy fog possible tonight (20-40% chance)

A modest increase in southerly winds aloft should help to pull
the plume of better quality moisture north through all of ENC
tonight. While forcing will be lacking, any area of moisture
convergence could support a few showers. In general, though, I
expect the main focus for showers to shift back offshore and
near the coast. Where skies clear out, light winds and a moist
boundary layer appear supportive of patchy fog (similar to the
past couple of nights). Widespread, impactful fog is not
expected, though.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
As of 4 AM Sat...An extended period of heat and humidity is
expected for Eastern NC this week with highs reaching the mid to
upper 90s, and heat indices topping 100 degrees almost every
afternoon, and exceeding 105 degrees at times. There will also
be some decent chances (40-50%) for showers and thunderstorms
Monday and Thursday/Thursday night as two weak fronts move into
the area.

Sunday and Monday...High pressure remains offshore Sunday, but
the gradient will tighten as a low pressure system passes by to
the north over New England. Winds will increase through the day
and gust to 20-25 mph in the afternoon, and potentially as high
as 30 mph along the coast. Increasing low level thicknesses will
lead to highs topping out in the mid 90s inland and the upper
80s to low 90s along the coast. When combined with the humidity,
heat indices will peak at 100-105 degrees in the afternoon.
Within the hot and humid airmass, isolated to scattered showers
and thunderstorms will develop, mostly driven by the sea breeze,
but not expecting anything substantial.

A cold front will move south into the area Sunday night, and
then slowly push through the area Monday into Monday night. Deep
moisture will increase ahead of this feature overnight Sunday
and bring better chances for rain to Eastern NC. The best
chances will be along the coast and Outer Banks as showers and
thunderstorms form across the coastal waters and push onshore.
There remains lower confidence on the evolution of showers and
thunderstorms Monday ahead of the front, with mixed solutions
from forecast guidance. Will maintain a 40-50% precip outlook,
but note the potential for higher rain chances for at least a
portion of the day Monday.

A hot and humid airmass will persist across the area, but the
somewhat unknown extent of shower and cloud coverage casts some
doubt on how hot it will get Monday afternoon. With that in mind
there is again potential for highs to reach the mid 90s inland,
and the low 90s along the coast, with heat indices peaking
100-105 degrees again.

Tuesday through Friday...Behind the weak cold front, slightly
cooler and drier high pressure will temporarily build in
Tuesday, especially along the coast where onshore flow will keep
temps mostly in the 80s. Farther inland the maritime flow will
moderate, and expect temps here to again climb into the low to
mid 90s. A few isolated sea breeze showers and thunderstorms
will possible as well.

Southerly flow quickly rebuilds Wednesday with low level
thicknesses rising as well. This will likely end up being the
hottest day of the week as temps soar into the mid to upper 90s
inland, and low 90s along the coast. Thankfully the drier
airmass will take time to moisten and humidity levels will be
relatively moderate, leading to heat indices "only" rising into
the low 100s to around 105.

Increasing moisture on Thursday ahead of the next weak cold
front will bring higher humidities, but also the threat of
scattered to potentially numerous showers and thunderstorms
(40-50% chance). Temperatures will again climb into the 90s, but
will increasing cloud cover expected, afternoon highs will
likely top out in the low to mid 90s across the area. However
increasing humidity will bring heat indices up to 100-105
degrees in the afternoon.

The cold front may stall across southern NC Friday and lead to
somewhat unsettled conditions again. Either way slightly cooler
temps are likely with heat indices remaining below 100 degrees.

&&

.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM /through 06z Sunday/...
As of 130 AM Saturday...

 - IFR/MVFR VIS likely overnight (60-80% chance)

 - Daytime SHRA risk Saturday (10-30% chance)

In the very near-term (ie. through 12z Saturday), the main
forecast challenge will be the MIFG/BR/FG potential. Recent
satellite imagery shows some low clouds or fog attempting to
develop, but thus far, nothing appears widespread. Meanwhile,
surface obs have reported IFR, or lower, conditions at times.
Based on webcams and satellite, it appears the reduced VIS is
due to shallow fog (MIFG). Through the night, however, it`s
possible that some depth to the fog could be realized, and we`ll
be closely monitoring this in case a more impactful period of
FG develops. For now, I`ve leaned towards more of a MIFG type of
scenario. During the day Saturday, heating of a moist airmass
will probably allow isolated to widely scattered SHRA to develop
(similar to yesterday). The coverage is expected to be too
minimal for a mention in the TAFs. However, reduced VIS will be
a risk with any SHRA that develops. The TSRA risk isn`t zero
today, but Saturday`s setup isn`t all that favorable for TSRA.
By Saturday evening, the SHRA risk looks to shift back offshore.
Similar to the next few hours, Saturday night looks to support
another round of shallow fog.

LONG TERM /Sunday through Wednesday/...
As of 4 AM Sat...Generally VFR conditions should exist outside
of convection this week which will be most widespread Monday
through Tuesday morning. Strong SW winds develop Sunday with
winds gusting 20-30 mph.

&&

.MARINE...
SHORT TERM /through tonight/...
As of 200 AM Saturday...

 - Scattered showers and thunderstorms possible through tonight
   (20- 40% chance)

Satellite imagery this morning reveals 2 notable features. One
is a weak area of low pressure currently moving ashore just
north of Jacksonville, FL. The other feature is an upper level
low spinning about 80-100 miles off the ENC coastline. The FL/GA
low may lift slowly north along the coast today, but shouldn`t
have a big impact locally. The upper level low, meanwhile, has
had an area of showers and thunderstorms associated with it, and
this will impact portions of the coastal waters this morning,
and potentially longer. Otherwise, southerly winds will be on
the lighter side through tonight (5-15kt), and seas will hold
around 2-4 ft.

LONG TERM /Sunday through Wednesday/...
As of 4 AM Sat...Small craft conditions are looking likely to
develop Sunday afternoon as the gradient increases ahead of a
cold front. Winds will likely be SW 20-25 kts, with gusts to 30
kts from Sunday afternoon through Monday morning with seas
rising to 5-7 ft. Winds will gradually decrease Monday as the
front moves into the waters, but some 25 kt winds may continue
across the southern waters south of Cape Hatteras. The front
will move through the waters Monday night with winds turning to
the N at 5-10 kts behind it. Expect winds to be NE 5-15 kts
Tuesday, and then SE at 5-15 kts Wednesday. Seas will subside to
3-5 ft by Monday evening, and then will become mostly 2-3 ft
Tuesday and Wednesday.

&&

.FIRE WEATHER...
As of 200 AM Saturday...

 - Elevated fire concerns possible Sunday

Recent RAWS observations suggest fine fuel moistures have
improved some, likely due to some shower activity the past 24
hours, and increasing ambient moisture off the Atlantic. This
combined with relatively light winds today should keep fire
concerns low. For any ongoing fires, the main concern today will
be a wind shift with the development, and passage, of the
seabreeze. Southerly winds increase on Sunday, becoming
sustained at 10-20 mph. RH will continue to increase, and is
forecast to only bottom out in the 40s and 50s. While not a
typical fire danger type of day, the breezy conditions and drier
fine fuels is noteworthy, especially for any fire that manages
to develop, or any ongoing fires. Wetting rainfall is still
possible on Monday and again Thursday.

&&

.MHX WATCHES/WARNINGS/ADVISORIES...
NC...Beach Hazards Statement through this evening for NCZ195-196-
     199-203>205.
MARINE...None.

&&

$$
SYNOPSIS...MHX
NEAR TERM...RM
SHORT TERM...RM
LONG TERM...SGK
AVIATION...RM/SGK
MARINE...RM/SGK
FIRE WEATHER...MHX