532
FXUS62 KGSP 070604
AFDGSP

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

.SYNOPSIS...
A weak front will move in from the north and become stationary near
the southern portion of the forecast area today. This front will
increase the chance for thunderstorm activity outside the mountains
through Sunday. An active pattern of afternoon and evening showers
and storms is expected to continue through next week.

&&

.NEAR TERM /THROUGH TODAY/...
As of 145 AM Sunday: Plenty of cloud cover expected thru the rest
of the night, which combined with elevated dewpts will keep warm,
muggy conditions thru daybreak. A few stray showers may develop,
thanks to the very moist BL, but overall, expecting quiet conditions
this morning.

Otherwise...broad longwave troughing is currently draped across much
of the CONUS from the Pacific Northwest to the Ohio Valley. Stout
upper ridging remains centered over California along with a second
ridge that has shifted off the east coast. A few showers may linger
into the overnight as southeasterly flow returns to the area and
the stalled boundary slowly lifts back north into the mountains. A
widespread deck of low stratus clouds is expected to develop, which
will further limit any cooling in the face of moisture return. This
will keep overnight lows on the mild side with upper 60s to low 70s.
By tomorrow, little change is expected with regards to the synoptic
pattern. Coverage of showers and storms is expected to be greater,
however, given the return of rich low-level moisture and ample
instability. Showers will likely develop earlier in the afternoon
with storms increasing in coverage as well, especially across the
escarpment and I-85 corridor. Morning cloud cover and an early
start to convection will not only keep temperatures in check,
but will also limit instability with surface-based CAPE progged
at 2000-2500 J/kg. As with any summertime convection, isolated
damaging wet microburst cannot be ruled out, especially where
multicell clusters/cell mergers occur.

&&

.SHORT TERM /TONIGHT THROUGH TUESDAY/...
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 /TUESDAY NIGHT THROUGH SATURDAY/...
As of 210 pm Saturday: The upper air pattern is expected to remain
relatively static during the extended, with a central Conus trough
expected to make only modest eastward progress, while the
subtropical ridge/associated Bermuda high is forecast to strengthen
across the western Atlantic. With such minimal changes in the
overall patter expected, the environment over the southern
Appalachians and vicinity is expected to remain more moist than is
typical for early summer. This moisture could be enhanced further
(albeit briefly) by the remnant circulation of T.C. Beryl, which is
forecast to lift across the TN and OH Valleys during mid-week.
Above-normal coverage of diurnal convection (60-70 PoPs across the
mountains; 50-60 across the rest of the area) is therefore expected
each day through the period. An excessive rainfall threat will
continue...and may actually worsen a bit as antecedent conditions
deteriorate locally. Temperatures are forecast to be within a degree
or two of climo through the period.

&&

.AVIATION /06Z 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...JDL
NEAR TERM...ARK/CP/TW
SHORT TERM...JDL
LONG TERM...JDL
AVIATION...ARK