563
FXUS62 KGSP 160152
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
952 PM EDT Wed May 15 2024

.SYNOPSIS...
Brief high pressure brings a mainly dry day on Thursday. Showers and
scattered thunderstorms return Friday and continue into the weekend.
Isolated afternoon and evening showers and thunderstorms are
expected early next week.

&&

.NEAR TERM /THROUGH THURSDAY/...
Evening Update...Still seeing showers and an occasional
embedded thunderstorm across the mtns this evening as mech lift
combines with upper occluded low passage. Coverage is becoming less
and expect a continued downward trend in activity as the evening
progresses into the overnight. With a widespread swath of precip
earlier and calming conds, expect a good chance of fog across the
mtn valleys east thru the NC fthills and NC/SC Piedmont. Areas east
of I-26 and south of I-40 will see the best chance of dense fog
formation and a Dense Fog Advisory will probably be needed and
issued by the midnight shift.

As of 210 pm EDT Wednesday: Much less active convective weather is
expected on Thu, as lower theta-E air filters in on NW flow, which
will combine with a weak subsidence inversion to yield very most
destabilization. There`s enough of a signal to support small PoPs
for diurnal convection (primarily SHRA) across portions of the
mountains during the afternoon. Max temps Thu will be a few degrees
above climo.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SUNDAY/...
As of 200 PM EDT Wednesday: Dry conditions are expected Thursday
night into early Friday morning thanks to upper ridging and sfc high
pressure. Ridging pushes east throughout Friday morning as an upper
low approaches out of the west. The upper low and its associated sfc
low will track over the Southeast throughout the weekend, but some
differences remain between the latest global model guidance sources
regarding both the timing and strength of the low. Both the GFS and
Canadian have the low lingering over the area on Sunday while the
ECMWF has the system pushing offshore. Nonetheless, went with likely
to categorical PoPs Friday afternoon/evening through early Saturday
evening. Capped PoPs to chance Saturday night into Sunday as
confidence is lower regarding if the low will stall over the region.
Models continue to diverge regarding the amount of instability and
shear available through the weekend, so confidence on the severe wx
potential continues to remain low. The Day 3 SPC Severe Wx Outlook
has the entire forecast area in a "General Thunder" Risk for Friday.
However, strong to severe storms cannot be ruled out as global model
guidance agrees that there will be decent deep shear associated with
the area of low pressure through the weekend. There is higher
confidence regarding the heavy rainfall/flooding threat throughout
the weekend as PWATs are expected to climb near/above 90th
percentile Friday afternoon through late Sunday. With wet antecedent
conditions already in place, additional rainfall this weekend will
allow hydro concerns to gradually ramp up. Lows will remain ~5-10
degrees above climo through the short term. Highs on Friday will be
near climo to a few degrees above climo, becoming a few degrees
below climo on Saturday. Highs on Sunday may return to near climo to
a few degrees above climo if convection does not linger over the
area.

&&

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
As of 230 PM EDT Wednesday: The ECMWF has the upper low pushing
farther east into the western Atlantic Sunday evening into Monday
while the GFS and Canadian have the low lingering over the eastern
Carolinas during this timeframe. Thus, maintained chance PoPs across
the northern zones through Monday. Upper ridging as well as sfc high
pressure will build into the region Tuesday into Tuesday night
leading to drier conditions. A cold front will approach out of the
west towards the end of the forecast period, allowing convective
chances to increase again from west to east. Both highs and lows
through the period should end up a few to several degrees above
climo.

&&

.AVIATION /02Z THURSDAY THROUGH MONDAY/...
At KCLT and elsewhere: A round of showers with a few embedded
thunderstorms possible will traverse the NC areas this evening into
the overnight. However, confidence is too low for any mention
outside of VCSH at KHKY this evening. Otherwise, expect lowering
VSBY and CIGS to IFR or LIFR at KCLT and KHKY, while winds may
remain mixed enuf and sfc tdd/s high enuf at KAVL/KGSP to preclude
IFR conds, yet still expect MVFR arnd daybreak. VFR conds likely
return to all sites aft 14z/15z as winds remain weak and align ne/ly
to n/y at KCLT. Elsewhere outside the mtns, winds will align more
sw/ly to nw/ly. KAVL will see winds setup nw/ly in channeled up-
valley flow.

Outlook: Convection active weather and associated flight
restrictions return Friday, likely continuing through the weekend.
Late night/early morning restrictions in low stratus and/or fog will
also be possible. Drier weather is expected to return early in the
next work week.

&&

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

&&

$$

SYNOPSIS...DEO
NEAR TERM...JDL/SBK
SHORT TERM...AR
LONG TERM...AR
AVIATION...SBK