279
FXUS62 KRAH 170700
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
300 AM EDT Mon Jun 17 2024

.SYNOPSIS...
Deep high pressure will build over the Mid Atlantic and Carolinas
through much of this week. A wave of low pressure will track
westward into the Southeast on Thursday into Friday, bringing rain
chances to our southern sections.

&&

.NEAR TERM /THROUGH TONIGHT/...
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.

&&

.SHORT TERM /MONDAY AND MONDAY NIGHT/...
As of 215 PM Sunday...

Monday be a near carbon copy of today.

The strong 593 dm upper level anticyclone centered over NC is
forecast to strengthen ever so slightly(594-595 dm). Surface ridge
axis and associated feed of drier, less humid air will remain along
eastern/coastal portions of the Carolinas. Weak lift, moisture
return and destablization on the western periphery of the low-level
ridge axis will continue to support mainly diurnal isolated to
widely scattered showers or thunderstorm over the higher terrain.
Like today, a few of these showers and weaker cells could develop or
move into the far western Piedmont, where gradual lifting of morning
stratus layer will occur. Elsewhere, dry conditions will persist.

Given no appreciable change in airmass, expect comparable temps to
today; highs ranging from mid 80s north/northwest piedmont to lower
90s south.

While the model signal is not as strong as tonight/Monday morning,
low-level E-SELY feed into the area will continue to promote the
development/advection of areas of stratus across central NC,
especially across western and southern NC.  Lows in the mid/upper
60s, with some lower 60s possible over the northern portions of the
coastal plain and piedmont.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
As of 300 AM Monday...

Still anticipate below normal rain chances for much of this week,
with increasing heat potentially reaching dangerous levels by the
weekend.

Wed-Thu aftn: A strong mid level anticyclone will be stretched
across PA/NJ/MD early Wed. It will remain quite strong through Thu
and drift only slightly S, its center over the Delmarva by Thu
evening with the ridge oriented W-to-E. Meanwhile, at the surface, a
strong high centered out over the NW Atlantic well E/offshore of New
England will continue to extend ESE through NC, weakening a bit
heading into Thu. As we`ll have low level thicknesses slightly below
normal Wed/Thu capped by anomalously warm/dry/stable mid levels and
below normal PW, convection chances will be extremely limited, and
will maintain a pop-free forecast. The long-fetch low level easterly
flow won`t be particularly strong through Thu but may still draw
enough Atlantic moisture into southern NC for a few more clouds
there, but otherwise skies should be no worse than partly cloudy.
The low level thicknesses offset by decent sunshine should result in
temps near to slightly above normal.

Thu evening-Fri: Our focus briefly shifts to a possible low level
inverted trough or a closed surface low that is expected to develop
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 or trough, 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. The latest runs of deterministic
models and ensemble systems generally favor an inverted trough
pushing W onto the Southeast coast Fri morning, which could result
in increasing clouds Thu night and a chance of showers and isolated
storms across our SE and far S sections Fri. But there is far from a
model consensus on this, and the low level flow on the NW side of an
onshore-moving trough could actually result in a backing low level
flow in our area to northeasterly with a reinforcement of low level
dryness and stability in central NC. Will lean toward the NBM`s
solution of low chance pops in our SE and S Fri afternoon for now.
With the mid level heat dome drawing closer, expect further warming
Fri to highs from around 90 to the mid 90s.

Sat-Sun: While we`ll start to see rain chances gradually trending
back toward climatology, the big story this weekend will be the
increasingly oppressive heat. Model differences predictably grow at
this range, but most indicate the mid level ridge center drifting SW
and expanding across NC Sat/Sat night before yielding a bit to a
broad northern stream trough and associated surface cold front
tracking through the Great Lakes region by Sun. The surface high
will push further out over the Atlantic, as a lee trough forms
through the W Piedmont well out ahead of the cold front. Our
thicknesses are expected to climb to around 10-15 m above normal Sat
and to 15-25 m above normal Sun, as our dewpoints rise through the
60s into the upper 60s/lower 70s. Shade air temps are expected to
peak at 94-100F both days, with heat indices of 95-106F and warm
lows mostly in the 70s, which when combined with sunshine and a
limited breeze will contribute to an increased risk of heat
illnesses. Regarding convection chances, with the trend to confluent
steering flow from the SSE through SSW and surface ESE flow pulling
in both Gulf and Atlantic moisture, the initially low PW through Fri
will rebound back over 1.5" over our far E and SE Sat and areawide
Sun. This, with lowering heights aloft due to the weakening mid
level ridge and approaching trough, will support small chance pops
mainly across the S each afternoon into early evening. -GIH

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
As of 109 AM Monday...

VFR conditions will mostly prevail over the 24 hour TAF period.
However, a brief period of MVFR ceilings appears possible at KINT
and maybe KGSO near sunrise this morning.  Any linger stratus should
lift to VFR by mid morning.  Otherwise expect another day of mostly
light ssely sfc flow and mostly dry conditions (a few stray showers
could trickle into the Triad later today).

Outlook: VFR conditons should largely persist through Friday.

&&


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

&&

$$

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