364
FXUS62 KGSP 110257
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1057 PM EDT Sat Aug 10 2024

.SYNOPSIS...
A cold front will spur scattered showers and thunderstorms this
afternoon, but will not be enough to stop hot and humid conditions
from developing.  High pressure will build in tomorrow and through
much of next week while the front stalls over the Southeast.  Daily
thunderstorm chances and cooler temperatures will persist for much
of the coming week.

&&

.NEAR TERM /THROUGH SUNDAY/...
As HRRR was insisting earlier this evening, have seen a
redevelopment of convection across the Piedmont just off the
escarpment. Have only made minor adjustments to pops and hourly
trends as earlier update captured CAM trends fairly well with the
front moving through, triggering convection along the instability
gradient.

Otherwise, the overnight period will be generally quiet with no
great chance of dense fog development near daybreak outside the mtn
valleys. Sun will be another weakly forced day with a good amt of
instability generated by the afternoon. So, expect a similar setup
for isol to sct tstms along the ern sfc bndry. Mins tonight will
remain a few degrees abv normal while highs climb into the u80s to
l90s east of the mtns and m80s across the mtns valleys.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
As of 149 PM EDT Saturday: A diffuse stationary front will remain
draped across the eastern reaches of the forecast area through
the short term, while WNW flow aloft brings spokes of vorticity
across the region on the periphery of a robust 500mb trough over
New England and Quebec.  The upper jet will remain displaced
a little to the north, but a few kinks in this flow will likely
affect the Carolinas.  In particular, on Monday night, a pronounced
shortwave will push across the region, driving a reinforcing cold
front out of the northwest and helping establish a deeper lobe of
high pressure north of the stationary front into Tuesday.

This`ll keep instability shunted off to the southeast both
afternoons, limiting or even preventing appreciable sbCAPE from
developing altogether across the northern and western portions of
the CWA.  For the southeastern 1/3 of the area, ensemble guidance
depicts anywhere from 1200 to over 2000 J/kg developing each
afternoon...more than enough to support some strong updrafts should
convection get going.  It`ll be difficult to get more widespread
initiation with the lack of synoptic forcing, but the CAMs which
go out that far depict at least widely scattered coverage south and
east of I-85 Monday afternoon.  With deep layer shear < 25kts both
afternoons, any outside severe risk would likely be wind-driven
courtesy of whatever DCAPE the environment can cobble together;
any heavy rainfall risk would be limited to areas where multiple
cells train over the same area.  Temperatures both afternoon will
be a little below normal...in the upper 80s...except for the Upper
Savannah River Valley, which will land around or even a degree or
two above normal both afternoons.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
As of 208 PM EDT Saturday: The synoptic pattern will remain
relatively unchanged through the bulk of the long range, with high
pressure continuing to ridge down the Eastern Seaboard and NW flow
aloft driving lobes of vort energy across the area.  A shortwave is
variously depicted arriving Wednesday or Wednesday night, either
enhancing convective coverage and associated severe risk if it
arrives earlier, or suppressing convection on Thursday if it arrives
later.  Timing remains in question based on the latest 12z LREF
cycle.  By the end of the week, any lingering frontal boundary over
the Piedmont/Midlands should be diffuse enough to no longer exert an
influence on the pattern, and the bulk of long-range ensemble
members indicate that the entire forecast area will be able to
destabilize on Wednesday and certainly on Thursday.  Having said
that, the synoptic pattern itself is fairly uncertain Friday onward,
so guessing at details at this point is fruitless.  High
temperatures will remain up to a category below normal through the
end of D7.

&&

.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
At KCLT and elsewhere: Convection has waned across most of the area
with only isolated TSRA closer to the mountains, though hires
guidance still wants to develop another round of convection over the
next few hours that could impact the Piedmont TAFs. Have not
included any mention of TSRA as confidence not high enough at this
time but will monitor for development. May see brief fog at KAVL
near daybreak and guidance is indicating some low VFR stratus
creeping near KCLT as well, but no restrictions at this time. VFR on
Sunday but introduced PROB30 in the out-periods at KCLT as most
guidance is pointing to a round of convection late in the day.
Except for some low-end gusts to start the period at KAVL, winds
should remain generally weak and out of the N to NE overnight, but
pick up 5-10kt during the day Sunday.

Outlook: Expect generally isolated to scattered diurnal convection
across the region each day through the middle of next week. Patchy
fog and low stratus will be possible each night in the mountain
valleys and in locations that receive rainfall.

&&

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

&&

$$

SYNOPSIS...MPR
NEAR TERM...SBK/TDP
SHORT TERM...MPR
LONG TERM...MPR
AVIATION...TDP