995
FXUS62 KGSP 071050
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
650 AM EDT Sun Jul 7 2024

.SYNOPSIS...
A weak surface front will increase the chance for thunderstorm
activity outside the mountains today. An active pattern of afternoon
and evening showers and storms is expected to continue into the
coming week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 645 AM Sunday: Low cigs are not as extensive as the model
consensus is depicting, and the mid and high clouds seem to be
thinning out somewhat on the nighttime RGB. This may result
in a little faster warming and more CAPE as well later this
morning. However, forecast soundings have a low CCL, so low clouds
may fill in after sunrise. So for now, no significant changes were
made with this update.

Otherwise...a weak frontal boundary will remain draped across the
forecast area today, as it`s roughly parallel to deep-layer SWLY
flow aloft. Copious moisture along the frontal zone (PWATs > 2
inches) will result in plenty of cloud cover today and another round
of convection this aftn into this evening. Moisture has worked back
NW into the mountains and convective initiation will likely start
along the ridges early in the aftn. The Piedmont may get off to a
later start, thanks to stratus taking its time scattering out. But
the latest guidance is in good agreement on outflows kicking off
convection east into the Piedmont (aided by convergence near the
front) by late aftn or early evening, with most of the forecast
area getting worked over before convection wanes. So likely to
categorical PoPs looks on track with locally heavy rainfall and
isolated flash flooding a concern again today. Instability will
be modest (generally 2000 J/kg or less), so severe threat will
be low. Cannot rule out a few strong wind gusts with the tallest
updrafts and any cell mergers. Highs will be near normal. Tonight,
plenty of lingering cloud cover and continued elevated dewpts should
make for another warm, muggy night. Lows a few degrees above normal.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
As of 145 AM Sunday...A moist and weakly forced atmos remains in
place thru the short range. Upper heights vary little Mon as Atl
moisture flux increases due to an eastward shift i Bermuda High
ridging. Very hard to determine a main focusing zone as llvl bndrys
remain ill defined. There is a decent signal for upslope
precip/convec across the BR escarpment and further west into the NC
mtns, however, and have the best PoPs there, pushing into the likely
range, yet lower than the more deterministic NBM output. A solid
chance precip will be maintained east of the mtns as PWATS remain
quite high and subtle terrain lift could help instigate multicell
outflow driven cells. Due to little changes in the overall synoptic
pattern, will go with a persistence type fcst featuring high precip
storms moving slowly northeast or east within the mean steering flow
aloft. Thus, expect a chance of hydro issues, esp considering the
increase in antecedent conds across localized areas. A few severe
level storms will be possible as well with damaging outflow winds
the main threat. More uncertainty on coverage and storm mode exists
Tue as sfc troffing may develop from the west while the remnants of
TC Beryl push up the MS Valley with differing timing solns seen on
the op models. So, PoPs have been adj/d down a little yet still
remain abv climo values. Max temps will hover near or arnd normal
levels each day with no widespread HI issues expected. Mins will be
held abv normal by a few degrees each morning.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 225 AM Sunday...A highly moist atmos remains in place to begin
the period, but this could change Wed into Fri as the guidance looks
to be trending drier. The latest op model runs all have remnant TC
Beryl more closed off and cyclonic then previous runs. This could
lead to higher moisture levels remaining tightly wound arnd the
former TC while dry continental air swings arnd the base into our
area from the west. Cross sections show a sigfnt lowering of theta/e
air in the mid/low levels and PWATS levels dropping arnd an inch.
This pattern change would curtail convection chances west of the
dry/density front and shift the focus of afternoon tstms across the
ern most zones of the FA into the latter ext period. Thus, have cut
back on PoPs giving some weight to this possibility. Still have abv
climo PoPs, but these may continue to lower on subsequent fcsts if
the latest pattern idea holds. Temperatures are still on track to
reach arnd normal thru the period.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
At KCLT and elsewhere: Lower than average confidence on the low cig
potential this morning, as guidance continues to be overdone. But
with very moist low-levels and patchy LIFR to MVFR clouds floating
around, expect some expansion of these low clouds during the
first few hours of the day. The clouds should lift to VFR-level by
around midday. Convection is expected to fire across the mountains
early in the aftn, then the combination of outflows and a stalled
front should trigger storms across the Piedmont late aftn thru
the evening hours. So TEMPOs for TS will be carried at all sites
(except PROB30 at KAND). Convection should wane by late evening,
and similar conditions expected again tonight as we had last
night. Plenty of mid and high clouds with patchy lower stratus and
fog forming. Once again, guidance seems overdone with prevailing
MVFR to LIFR cigs overnight thru Monday morning. Nevertheless,
some low cigs will likely form across most of the area tonight.

Outlook: An active summertime pattern continues for most
of the upcoming week, leading to scattered to numerous
showers/thunderstorms and possible restrictions each
afternoon/evening. Fog or low stratus may develop each morning,
especially over areas that received rain the previous day.

&&

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

&&

$$

SYNOPSIS...SBK
NEAR TERM...ARK
SHORT TERM...SBK
LONG TERM...SBK
AVIATION...ARK