114
FXUS62 KGSP 160531
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
131 AM EDT Thu May 16 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 TODAY/...
Midnight Update...no major changes were made to the forecast.
With the axis of the upper trough now decidedly east of the area,
convective activity is over and will not resume tonight.  Dry,
postfrontal air is surging into the area at this point...and
frankly, you can just feel how much less muggy it is stepping foot
outside the office.  Many sites across the NC Piedmont are already
seeing reduced visibility as radiative cooling gets underway,
so while no DFA will be issued yet, it`s more or less a matter of
time before one is needed.

Otherwise...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 /TONIGHT 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 /06Z THURSDAY THROUGH MONDAY/...
At KCLT and elsewhere: Generally quiet across the area, with the
main concern for the entire TAF period being visibility through
daybreak Thursday.  Already, there`s a corridor of dense fog
developing across the NC Piedmont, with KHKY already seeing LIFR
restrictions leading up to the 06z TAF issuance!  Expect gradual
expansion of this area and worsening of overall conditions through
daybreak - LIFR to VLIFR restrictions seem likely at this point -
after which fog will quickly scatter out.  Thereafter, we can
expect pleasant VFR conditions through Thursday and Thursday
night, with some scattered capped cu likely to develop during the
afternoon.  Winds will be mostly out of the NW, although some of
the southernmost zones could see a period of light WSW winds during
the afternoon hours, quickly toggling back to NW in the evening.
Mountain valley fog/low stratus may occur again Thursday night.

Outlook: Convection active weather and associated flight
restrictions will 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/MPR/SBK
SHORT TERM...AR
LONG TERM...AR
AVIATION...MPR