278
FXUS62 KGSP 101850
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
250 PM EDT Wed Jul 10 2024

.SYNOPSIS...
A cold front associated with the remnants of Beryl will usher
in drier air through Thursday. Moisture gradually returns Friday
into the weekend, bringing an increase in afternoon and evening
showers and storms. Typical mid-summer temperatures and daily
isolated to scattered storms expected early next week.

&&

.NEAR TERM /THROUGH THURSDAY/...
As of 217 PM EDT Wednesday: A weakening cold front is exiting the
NC mountains at this point, leaving zones to its west stabilized
and zones to its east still warm, moist, and unstable.  Satellite
imagery depicts a growing field of cumulus east of the boundary,
but with little to no vertical development even along the direct
frontal circulation.  Temperatures, meanwhile, have surged into
the upper 80s and lower 90s across much of the area, allowing the
heat index to climb into the upper 90s, especially across the I-77
corridor, as we barrel toward peak afternoon heating.

It`s possible that we could get a few showers out of the NC
Foothills as the front continues its march eastward, as the
atmosphere is unstable enough that it really shouldn`t take much
to set something off.  But given how warm the midlevels are, it`s
debatable whether charge separation will even be possible, and
even run-of-the-mill thunder chances look very low.  Dewpoints will
crash behind the front as drier high pressure settles in, and skies
should clear out tonight and permit lows to fall to around normal,
perhaps even a degree or two below.

Thursday will be another clear, dry day.  Dewpoints are expected
to drop into at least the low 60s, or even upper 50s based on some
drier ensemble guidance, and in a suppressed environment...so
Thursday will be a beautiful day albeit with above-normal
temperatures once again hitting the low to mid 90s.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
As of 223 PM Wednesday...The short term forecast starts off tomorrow
night with a shortwave trough draped across the Mississippi Valley
and a stout upper ridge off the coast of New England. A closed upper
low associated with a tropical upper tropospheric trough is also
progged to be sandwiched between these two features and situated
just off the coast of the Carolinas. At the surface, the cold front
pushing across the area today is forecast to stall over the Coastal
Plain with a pronounced coastal baroclinic zone extending down the
coast towards northern Florida. Periods of convection along the
coast and just offshore will help to instigate a mesolow which
guidance further deepens into a weak tropical low along the coast by
tomorrow night. An attendant inverted surface trough will also
extend across the Coastal Plain and help to focus showers and
thunderstorms within a deep tropical moisture plume. Heading through
the overnight, upper height gradient will increase between the
shortwave trough lifting across the Ohio Valley and the offshore
ridge. This will in turn strengthen onshore flow and help to push
the stalled frontal boundary back west. Dewpoints are expected to
surge back into the low to mid 70s across far eastern portions into
the I-77 corridor as the frontal boundary retrogrades. The return of
deep moisture will also be accompanied by an uptick in coverage of
showers heading into the predawn hours Friday morning. How far west
the front retreats remains uncertain with most guidance keeping
deeper moisture confined to the I-77 corridor through the day
Friday. Thus, will keep the highest PoPs focused here with only
chance to slight chance elsewhere. Little to no convection is
expected west of the boundary in the drier air, so the placement of
the front will be key as to who ultimately gets in on some much
needed rainfall.

By Saturday, surface features to help focus convection become much
more nebulous with the weak low filling beneath convergent upper
flow and any inverted trough hard to depict. Thus, despite the
passage of a trough axis to the north, coverage of diurnal convection
will be scattered at best. Temperatures Friday will be warm outside
of thicker cloud cover along the I-77 corridor with all locations
returning to the low 90s on Saturday.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
As of 244 PM Wednesday...A hot and humid summer pattern returns
Sunday into next week as the region becomes situated south of a
broad trough extending from the Northern Plains into New England.
Upper ridging is forecast to build into the area from the Southern
Plains with warming low-level temperatures and at least weak onshore
flow from the Gulf/Atlantic helping to maintain moist upper 60s to
low 70s dewpoints. Temperatures will climb back into the mid 90s on
Sunday with mid to upper 90s Monday into Wednesday. This will in
turn foster oppressive humidity with heat indices in the low 100s.
Heat advisories are not out of the question, especially by mid week.
As for convection, a lack of forcing from both synoptic/mesoscale
features will greatly limit coverage each day to isolated/scattered.

&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
At KCLT and elsewhere: A quiet VFR TAF period is on tap for the
entire terminal forecast area.  A weak and mostly-dry cold front
is making tracks into the NC foothills circa 1730z and ushering in
cooler, drier air into the region.  The environment`s not quite
capped, but it`s also not exactly ripe for convection, so while
some isolated showers can`t be ruled out along the I-40 corridor
and the NC I-77 zones, confidence is low.  15-20kt gusts out of
the SW are expected as the afternoon wears on and the frontal zone
passes us by...afterward, winds should die down and any FEW/SCT
mid-level cloud bases will dissipate, giving way to FEW/SKC and
a steady NW wind overnight.  Winds will stay elevated enough to
preclude any chance of morning fog/low stratus at any of the TAF
sites...although areas of the Little Tennessee Valley could see
some patchy fog around daybreak.  Expect another few to scattered
cu field to break out Thursday afternoon, but not even isolated
showers are expected.

Outlook: Moisture will begin to filter back in from the southeast
on Thursday night, resulting in increasing clouds and rain chances
by Friday. Shower and thunderstorm chances will increase into the
weekend, along with associated flight restrictions.

&&

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

&&

$$

SYNOPSIS...DEO
NEAR TERM...MPR
SHORT TERM...TW
LONG TERM...TW
AVIATION...MPR