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878
FXUS62 KRAH 161754
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
155 PM EDT Sun Jun 16 2024

.SYNOPSIS...
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Deep high pressure will build over the Mid Atlantic and Carolinas
through mid week.
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&&

.NEAR TERM /THROUGH TONIGHT/...
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As of 155 PM Sunday...

Afternoon satellite imagery reveals that continued moist
upslope/upglide has persisted across the west and northwest
Piedmont. Dewpoints in this region are in the upper 60s, while they
have mixed out into the upper 50s to low 60s over the Coastal Plain.
With the high to our north and east, southeast flow has kept clouds
socked in over the Triad region, with temperatures hovering in the
upper 70s to near 80. Spotty showers continue to develop in this
flow, likely driven by some weak instability above the surface
inversion. As the afternoon continues to wear on, we should see some
breaks in the clouds to allow highs to rise some 3-4 degrees from
current readings. Elsewhere, highs are on track with most areas in
the mid/upper 80s, to low 90s in the Sandhills.

Mesoanalysis shows that the majority of the surface-based and mixed-
layer instability is confined across the NC mountains and near KCLT.
Satellite imagery also reveals little vertical growth of cumulus in
central NC at the moment. As such, there remains that low-end chance
of a shower or storm in the west into the early evening, but most
areas are likely to be dry.

The moist upglide will continue overnight tonight across the west,
with a better signal of low stratus in the northwest Piedmont. Three
out of the 5 high-res models also show weak shower activity
developing toward sunrise Mon over the Triad once again, tied to
instability above the surface-based inversion. We have introduced
low-end rain chances as a result. Overnight lows are expected to be
in the middle 60s across the east to upper 60s to low 70s over the
west.
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&&

.SHORT TERM /MONDAY AND MONDAY NIGHT/...
As of 217 AM Sunday...

The anomalous mid-level ridge will amplify up into the northeast US
on Sunday.  This will promote yet another hot and dry day for
central NC. Low-level esely flow will persist, but the deeper
moisture/instability axis will shift further northwest into the TN
Valley on Monday. Most afternoon convection will follow suit, as
central NC remains primarily dry.  Highs will once again reach the
lower 90s. Dew points will struggle to mix out a bit more compared
to Sunday, and thus expect a bit more uncomfortable sensible
weather.  While heat indices will stay well below advisory criteria,
given the persistent hot temperatures we`ve experienced recently,
it`s advised to practice heat safety including hydrating and taking
frequent breaks in shady areas if participating in outdoor
activities.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
As of 300 AM Sunday...

Hot and dry conditions will remain the story through much of the
upcoming week, with temperatures generally above normal and rain
chances below normal, at least until later in the week. There is a
small chance for increasing moisture into the Southeast states mid-
to-late week, but confidence in this is very low.

A strong mid level anticyclone will be parked over VA/NC early Tue,
assuring warm/dry/stable air aloft and suppressing deep convection.
At the surface, a strong high centered out over the NW Atlantic well
offshore of New England will continue to extend ESE through NC. The
extended duration of long-fetch onshore-directed easterly flow along
the southern edge of the surface ridge could bring some enhanced
cloudiness into our area during the mid week, including clouds
associated with an inland-progressing sea breeze, mainly across our
southern sections. However, with low PW in place, any precipitation
would be restricted to isolated shallow showers, with the strong mid
level ridge greatly limiting thunder potential Tue. The mid level
anticyclone`s center is expected to wobble to the NE to be centered
over NJ/NYC by early Thu, before then drifting back SE and S to off
the NC coast or over the coastal Carolinas by Sat. The surface
high`s center is expected to drift southward during this time, all
the while extending across NC, although models depict a lee trough
developing over the W Piedmont by Sat as the surface ridge weakens.
The result is below normal PW persisting through much of Thu, then
as the mid level anticyclone drifts down to our latitude, the
veering of low-mid level winds to deep southeasterly is expected to
draw improving Atlantic-source moisture and higher PWs into our
area, particular across southern and western NC. So after very low
to no rain chances through Wed, we should see pops returning to the
area by Thu-Sat, low N and higher in the S and W, with upslope
directed flow helping to enhance pops over the SE-facing slopes into
the foothills.

It must be noted that a possible forecast complication arises by Wed
night. The latest runs of a few of the deterministic global models
depict an inverted trough or a closed surface low developing on the
southern end of the surface ridge a few hundred miles E or ENE of
the northern Bahamas by mid week. Such a low, if it forms, may be
tropical (warm core) in nature, not an unexpected turn of events
given long easterly low level fetch, the time of year, the extremely
warm ocean waters, and the models` consensus of very weak upper
level shear in this area. But the location and timing of such a
feature on this handful of deterministic models still vary quite a
bit, by hundreds of miles and 24-36 hrs, respectively, with varying
strengths as well. The EC-AIFS doesn`t show any discernible low or
trough at all, nor does the LREF mean, and any signal within the
parent ensemble means is, as one might expect, a bit washed out and
tough to track, although the GEFS low centers are somewhat better
clustered. At this point, the most likely scenario is an inverted
trough or perhaps a low pushing westward and onshore somewhere
between CHS and MIA between Wed night and midday Fri, with the
better rain chances holding to our S as ridging dominates much of
NC. But again, confidence is low, so stay tuned for later forecasts.

While the mid levels will be quite warm over the region this week,
the comparatively cool surface ridge will keep our low level
thicknesses near normal through Thu, as the most dangerous heat
holds to our N over the southern Great Lakes region into the Ohio
Valley and Northeast states. Temperatures should still be roughly a
category above normal Tue-Thu, with plentiful sunshine. After this
time, however, there are strong indications of increasing heat
across our area starting Fri but especially over next weekend, when
the heat could become a significant health hazard for NC, with shade
air temperatures peaking in the mid-upper 90s. -GIH

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
As of 110 PM Sunday...

VFR conditions are expected to start the TAF period. Moist
upslope/upglide has persisted across the Triad terminals today.
Instability trapped below the inversion has led to spotty showers.
These showers are possible to start the TAF period. Afternoon
convection looks to stay confined west of GSO/INT later this
afternoon/evening. The moist southerly flow around the high to our
northeast will favor a better chance of MVFR to perhaps IFR stratus
over GSO/INT Mon morning. Confidence is highest at INT and lesser at
GSO. These sub-VFR CIGs should lift to VFR by the end of the TAF
period. Some showers may also develop at GSO/INT Mon morning to
early afternoon with continued weak instability above the subsidence
inversion.

Outlook: An isolated shower/storm is possible at GSO/INT Mon
aftn/eve. Otherwise, VFR conditions are expected the remainder of
the period.

&&


.RAH WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

SYNOPSIS...Hartfield
NEAR TERM...Kren
SHORT TERM...Luchetti
LONG TERM...Hartfield
AVIATION...Kren