512
FXUS62 KGSP 142304
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
704 PM EDT Wed Aug 14 2024

.SYNOPSIS...
Dry high pressure gradually builds in from the north through
Thursday, resulting in mainly isolated afternoon showers and
thunderstorms in the mountains. The high will drift east off the
East Coast Friday, as a cold front approaches from the west over
the weekend. The front will bring a return of better chances of
shower and thunderstorms through Sunday, then lower chances early
next week with temperatures near normal.

&&

.NEAR TERM /THROUGH THURSDAY/...
As of 701 PM EDT Wednesday: A scattering of showers has developed
across the mountains as expected with most of the activity confined
from Macon County to Transylvania County. These showers will slowly
drift south this evening with some activity potentially spilling
into the western Upstate with a stray shower festering into the
overnight. Very limited instability will make it difficult to
achieve deep enough cores for even lightning, thus no hazards are
expected. Limited rainfall rates and low PWATs will preclude any
threat for locally heavy rain. The forecast remains largely on track
and only minor adjustments were needed.

Tonight looks like it should be fairly quiet thanks to sfc high
pressure ridging down from the Mid Atlantic region. The most
likely problem will be locally dense fog/low stratus in the mtn
valleys and around some of the larger lakes and rivers, given
the high amounts of low level moisture still hanging around. A
more interesting potential problem, which admittedly has a low
probability, would be rain over northeast Georgia and the western
Upstate. This is only mentioned because most of the CAMs have
some flavor of taking a few showers southward tonight off the
higher terrain, then stalling them as they run into a developing
light SE flow around the back side of a weak 850 mb high, then
drifting them back upslope toward the Balsams. Could this result
in a surprise heavy rain scenario? Probably not, because fcst
soundings show only shallow instability, modest precipitable water,
and fairly high MBE velocity, so we are missing some ingredients,
but the warm cloud depth remains high. Low temps will be below
normal across the NC portion where drier air has filtered in,
but around normal over the Upstate and northeast Georgia where
we may keep more clouds. For Thursday, expect a similar day, with
another round of ridgetop convection in the afternoon. High temps
may creep back up a few degrees.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
As of 210 PM EDT Wednesday: An upper low moving across the Great
Lakes helps build a trough into the area through the period. High
pressure over the area slides east as a cold front approaches from
the NW on Friday and into the area on Saturday. The right entrance
region of the upper jet moves into the area as well. Expect
scattered convection mainly over the mountains Friday afternoon
which could last well into the night. Convection spreads across the
area Saturday as moisture and forcing increase with the front. A
moderately unstable air mass and moderate bulk shear could move in
with the front as well creating the potential for organized, and
possibly severe, convection. Highs will be near to a little above
normal both days. Lows Thursday night near to slightly below normal
rise to above normal Friday night.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
As of 155 PM EDT Wednesday: An upper trough axis slowly crosses the
area Sunday and Monday. The cold front from Saturday slowly moves
east of the area during this time. Looks like moisture and weak
instability will be best over the mountains both days and the NC
foothills and Piedmont on Sunday for isolated to scattered diurnal
convection. Dry high pressure builds in on Tuesday resulting in a
dry forecast. Moisture return begins on Wednesday with generally
isolated diurnal convection. Highs will be near to slightly above
normal with lows near to slightly below normal.

&&

.AVIATION /23Z WEDNESDAY THROUGH MONDAY/...
At KCLT and elsewhere: Quiet VFR conditions are expected to continue
through much of the evening and into the overnight hours within a
relatively dry airmass. A couple scattered showers are ongoing
across the mountains and some of this activity may drift near KAVL
over the next couple hours. Otherwise, the main focus overnight will
be the potential for another round of locally dense fog and low
stratus with IFR restrictions possible. Confidence is highest at
KAVL and KHKY, but shallow patchy ground fog cannot be completely
discounted at any terminal around sunrise. VFR conditions will
return shortly after sunrise tomorrow morning and persist through
the day with only a couple isolated mountain showers expected.

Outlook: Coverage of convection increases Friday into Saturday as a
cold front approaches out of the west. Patchy fog and low stratus
will be possible each morning in the mountain valleys and in any
locations that received heavy rainfall the day prior.

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.

&&

$$

SYNOPSIS...DEO
NEAR TERM...PM/TW
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...TW