751
FXUS62 KGSP 070732
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
332 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 330 AM Sunday: 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 /08Z SUNDAY THROUGH THURSDAY/...
At KCLT and elsewhere: Despite plenty of high-based cigs, MVFR
to LIFR clouds are beginning to form across the lower Piedmont,
and should generally expand in coverage thru the pre-dawn hours,
resulting likely IFR cigs at all the Piedmont sites by daybreak. The
clouds will then be slow to lift to MVFR and finally scatter out
to VFR by around midday. This may delay the diurnal convection,
but with such moist air mass, expect scattered to numerous SHRA
and TSRA starting in the mountains, then generally working east
late aftn into the evening. Will go with a TEMPO at KAVL, where
confidence and coverage warrants, while the other sites can still be
handled with PROB30 groups. Convection should wane by late evening,
leaving plenty of mid clouds around thru 06z. Areas of MVFR to
LIFR cigs and patchy fog will likely form in the 06z-12z time
frame again Monday morning. Winds will be light thru the period
(except possible gusts and variable around convection).


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