686
FXUS62 KGSP 120721
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
321 AM EDT Wed Jun 12 2024

.SYNOPSIS...
Dry conditions will continue through the week under weak high
pressure. Isolated to widely scattered showers and thunderstorms are
expected early next week as a weak cold front approaches from the
north.  The hottest days are expected to be Friday and Saturday,
then the heat should continue into next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 315 AM EDT Wednesday: Starting to see the low- and mid-level
clouds retreat northward with some clearing over the Upstate and
northeast Georgia. The one monkey wrench being thrown into the
forecast is a band of cirrus moving in from the southwest. Adjusting
sky cover and temperatures based on this development. The forecast
still remains on track.

Retreating upper trough over the northwestern Atlantic will
set the stage for rising heights and the flow aloft to somewhat
flatten out. Model guidance are picking up on a weak shortwave
moving across the Deep South during the period and will fetch
a deck of upper-level cirrus over the area. Weak surface high
pressure will continue to control the sensible weather as the
high gradually shifts offshore the Mid-Atlantic and Carolina Coast
through the period. Expect winds to steadily come out of the east
to southeast during the daytime period, providing a light Atlantic
fetch across the area. In this case, shallow moisture will settle at
the top of the boundary layer and underneath a mid-level subsidence
inversion. Expect more cloud cover than Tuesday as a result during
peak heating, but mentionable PoPs will remain out of the forecast
due to the warmer air aloft helping to suppress the atmosphere
and no real trigger for precip. Dewpoints will increase today to
go along with a rise in temperatures as our summertime pattern
begins to really settle in across the CFWA starting today. Expect
afternoon highs to rise around a category or so compared to Tuesday
with most locations reaching at or slightly above normal. Lingering
cloud cover overnight will keep what would be otherwise a very
good environment for radiational cooling. Overnight lows will be
near normal as a result.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
As of 250 am EDT Wednesday: Upper flow will become increasingly
anticyclonic during the short term, as high pressure gradually builds
toward the Southeast from the Southern Plains. The result will be a
continued warming trend, with rather hot conditions expected by the
end of the period. Meanwhile, despite steadily increasing humidity,
conditions will remain unseasonably dry as the atmosphere becomes
suppressed due to warming temps aloft/increasing subsidence. Some
short term and convection-allowing guidance seem rather overdone
with ridgetop convection Thu afternoon, as forecast soundings appear
quite inhospitable to deep convection. Still...we`re getting to the
point of the year in which it`s difficult to not get at least a
little diurnal convection going across the high terrain...so slight
chances for showers are carried there during the afternoon/early
evening. Much of the same can be said of Friday...although a short
wave trough passing north of the region is expected to send a weak
frontal boundary through our area during the afternoon.
Nevertheless, forecast soundings appear no less hostile to
convective development than they do on Thursday, so PoPs are once
again limited to late day ridgetop slight chances. Temperatures will
be above normal through the period, with Friday expected to the
hottest day of the year so far...with mid 90s expected across
portions of the Piedmont.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 300 am EDT Wednesday: Upper heights will continue to rise
during the early part of the extended, as anticyclone becomes
centered over the Southeast during the weekend, before likely
lifting into the Mid-Atlantic early in the new work week. As a
result, the atmosphere will remain quite suppressed for vertical
motion on Saturday, with sparse-at-most mountain diurnal convection
expected. As the anticyclone begins to drift away from the area
early next week, conditions will steadily become more favorable for
(mainly) mountain convection Sunday through Tuesday afternoon/
evening. In fact, some global models lift a short wave trough north
through the TN Valley and southern Appalachians by the end of
Monday, which could further increase the convective potential for
far western areas. In general, forecast PoPs trend toward
climatology early next week...20-30 PoPs mainly across the western
half of the area...with a small increase over these values Monday
afternoon. After another day with max temps 5+ degrees above normal,
conditions will moderate a bit thanks to falling heights, although
max temps are still forecast to be a couple of degrees above climo
through the end of the period. Increasing humidity will result in
above-normal mins.

&&

.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
At KCLT and elsewhere: VFR conditions will prevail through the
forecast period. Ongoing stratocu will hold steady over the next
few hours before scouring out around daybreak or shortly after,
which is reflected in the prevailing lines at all TAF sites. Model
guidance still hints at some flavor of mountain valley fog, but
not expecting it to fill in at KAVL as cloud cover will hold fog
development until later in the overnight period. Winds will be
light and variable overnight with 060-090 cigs underneath the
current cloud deck. High pressure will remain in control through
the rest of the period and keep winds on the lighter side with
mainly a south to southeasterly component. FEW to SCT fair weather
cu will develop once again during peak heating with upper-level
cirrus hovering overhead as well.

Outlook: Surface high pressure remains over the area through the
end of the week with minimal chance for convection and associated
flight restrictions.

&&

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

&&

$$

SYNOPSIS...DEO
NEAR TERM...CP
SHORT TERM...JDL
LONG TERM...JDL
AVIATION...CAC