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000
FXUS62 KGSP 201848
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
248 PM EDT Sat Apr 20 2024

.SYNOPSIS...
Much cooler temperatures and widespread light rain is expected
overnight into Sunday with drier weather returning by Monday. Warmer
weather returns by Tuesday and continues through the workweek.

&&

.NEAR TERM /THROUGH SUNDAY/...
As of 245 PM EDT Saturday: Mostly sunny skies are noted across most
of the forecast area this afternoon with the exception of areas
along the NC/TN border. Seeing some passing upper cirrus at times as
well as daytime cu that has developed thanks to afternoon heating.
With plentiful insolation across the western Carolinas this
afternoon, SBCAPE values up to 1500 J/kg is expected. With up to 45
kts of effective shear in place this afternoon per the latest SPC
mesoanalysis, an isolated strong to severe storm or two cannot be
entirely ruled out. The Day 1 SPC Severe Wx Outlook has introduced a
Marginal Risk for isolated severe storms across the far southeastern
tier of the forecast area, which includes eastern Chester County and
eastern York County in SC as well as all of Union County in NC. Any
storm that manages to become severe will have the potential to
produce damaging wind gusts and large hail. Already seeing some
showers and thunderstorms starting to develop near the NC/SC border
as of the writing of this AFD. Thunderstorm chances will linger
through sunset but should wane shortly after with the loss of
daytime heating. Temps this afternoon have already climbed into the
upper 70s and lower 80s east of the mountains. Thus, highs should
end up around 5-10 degrees above climo this afternoon outside of the
western NC mountains.

Drier conditions are expected this evening through late tonight as
the eastern periphery of dry high pressure extends into the western
Carolinas. However, rain chances will gradually ramp up across the
forecast area overnight into late Sunday morning as in-situ CAD
develops and as isentropic ascent increases. Lows tonight should be
3-5 degrees above climo thanks to increasing clouds and rain. Rain
will linger through much of the day on Sunday before gradually
tapering off from west to east late Sunday afternoon into early
Sunday evening. Thus, have categorical to likely PoPs from early
Sunday morning through late Sunday afternoon. Thunderstorms are not
expected to develop thanks to the CAD. Highs on Sunday will end up
15-20 degrees below climo thanks to the wedge and will struggle to
reach into mid to upper 50s east of the mountains.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
As of 100 PM EDT Saturday: Rainfall directly associated with the
southern stream wave will pull away from the area Sunday evening
with just a small lingering pop early in the Piedmont areas. A
vigorous mid level trough will swing quickly through on Monday. This
system will have little moisture with which to work, so the main
impact will be just keeping conditions cooler than climo for Monday.
Flat mid level ridging and weak surface high pressure will be the
main weather influences for Monday night and Tuesday.

Temperatures Sunday night and Monday night will be cool with lows in
the 30s in the mountains and lower to middle 40s in the Piedmont.
Right now, it looks like temperatures will remain just above and
frost/freeze concerns in the mountain valleys, but this will need to
be watched closely. Highs Monday will be nearly 10 degrees below
climo warming to around 3 degrees below climo on Tuesday.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
As of 115 PM EDT Saturday: A mid level trough will move from the
Great Lakes into the Northeast for the middle of the week. This will
push a weak and mainly dry cold front into the area on Wednesday.
Mid level heights will quickly rebound from this trough for Thursday
and Friday. Another system will impact the area late in the week
with some showers possible by Friday, mainly in North Carolina.
Temperatures for the middle to end of the week should be pretty
close to climo.

&&

.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
At KCLT and elsewhere: Sfc high pressure will dominate through late
this evening leading to mostly dry conditions. However, isolated
thunderstorms may develop late this afternoon into early this
evening thanks to ample daytime heating. Thunderstorms look to
develop around/near KCLT, KGSP, and KGMU from roughly 21-24Z so have
introduced TEMPOs at these terminals. Could not rule out the
possibility of an isolated strong to severe storm impacting any of
the aforementioned terminals. Dry conditions will return around
sunset due to the loss of daytime heating. The rest of the terminals
should remain dry this afternoon and early evening. A few terminals
are reporting low-end gusts this afternoon; KAVL, KGMU and KAND.
Intermittent low-end gusts should stick around through this
afternoon before gradually diminishing this evening. The exception
will be KAVL where low-end gusts may linger through late this
evening before tapering off. Winds will start out W`ly across the SC
Upstate terminals early this afternoon before gradually turning N`ly
this evening. Winds will start out NW`ly at KHKY and KCLT early this
afternoon before gradually turning N`ly this evening. Winds east of
the mountains will gradually turn NE overnight and will remain NE
through Sunday. Winds will remain NW at KAVL through the entire 18Z
TAF period. Both restrictions and rain chances will return overnight
into early Sunday morning as in-situ cold air damming develops. Cigs
will gradually lower from west to east early Sunday morning becoming
IFR by late Sunday morning. -RA will linger through the end of the
18Z TAF period for all terminals thanks to isentropic ascent. No
thunderstorms are expected with stable cold air damming in place.
Cigs may lift to low-end MVFR levels early Sunday afternoon but
confidence on this is low at this time.

Outlook: VFR and dry conditions return Sunday night into early next
week as high pressure builds into the region from the west.

&&

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

&&

$$

SYNOPSIS...SCW
NEAR TERM...AR
SHORT TERM...SCW
LONG TERM...SCW
AVIATION...AR