852
FXUS62 KGSP 111055
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
655 AM EDT Fri Jul 11 2025

.SYNOPSIS...
Active summertime weather will continue thru the weekend with
numerous showers and thunderstorms each day. High temperatures
will increase each day through Monday, trending back to around
normal for the middle of next week behind a weak cold front.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 650 AM EDT Friday: Stout low stratus deck has overlaid the
southern half of the CFWA. There are some areas of patchy dense fog,
mainly near bodies of water and is too isolated for any dense fog
product at this time. Any low stratus deck and lingering fog should
scatter out quickly after daybreak as low-level mixing gets underway
followed by summertime destabilization. Otherwise, the forecast
remains on track with only minor tweaks made based on current
observations and latest trends.

Subtle mid-level trough will be in midst of slipping east of
the region, while weak height rises push in from the south as a
weak anticyclone slowly deepens over Florida and the Gulf. PWAT
values between 1.50"-2.00", 2000-3000 J/kg of SBCAPE, and <20
kts of deep layer shear will set the stage for typical peak diurnal
pulse convection. Slow moving storms may result in localized
flooding as well with high rainfall rates. Convective initiation
will start over the ridgetops across the southern Appalachians and
the Blue Ridge Escarpment during the early afternoon hours, followed
by downstream initiation with the presence of an inverted ridge on
the lee of the Appalachians. Weak westerly flow aloft will help to
induce drier mid-levels to go along with decent inverted-v low-
levels, suggesting the threat for wet microbursts will be evident,
with a few potentially producing strong to severe damaging wind
gusts as DCAPE values range between 800-1200 J/kg. Associated
outflow boundaries will help to carry convective initiation further
east across the Piedmont zones later in the afternoon into the
evenings hours, leading to a similar severe threat and weather
pattern compared to the past few days. Most of the activity should
gradually dissipate after sunset with the loss of peak diurnal
heating. Lingering convective debris and tight dewpoint depressions
will likely bring another round of low stratus and fog overnight
Friday, especially if the convective debris clears out early on
during the overnight period. Overnight lows will be similar to
tonight with low 70s across the Piedmont and mid to upper 60s across
the mountains and foothills.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
As of midnight Friday morning: Upper anticyclone to remain centered
over the eastern Gulf Saturday. Meanwhile a broad shortwave will
drift over the Mississippi Valley. As ridge builds, and with the
approaching trough, a weak warm front appears to ride over the CWA
from the SW. While PoPs mainly will be driven by diurnal
instability, model QPF response suggests the front may lead to
earlier than usual initiation over the mountains and GA/SC foothills.
The warm front brings PWATs back a little above normal, with similar
numbers persisting into Sunday. 0-6km shear remains weak, on the
order of 10 kt. Despite the PWATs, sfc-midlevel delta-theta-e values
are marginally favorable for severe downbursts. Pulse storms should
be the preferred mode with seasonable threats of torrential rainfall
and isolated instances of damaging wind. PoPs overall are a little
above climo, mostly high chance for the Piedmont and likely over the
mountains.

The ridge effectively retrogrades slightly as the trough moves across
the Great Lakes and lower OH Valley; low-level flow turns more
northwesterly for Sunday and a more pronounced lee-trough QPF
response is seen that afternoon compared to Sunday. Mountain PoPs
trend a bit lower that day but remain similar in the lower Piedmont.
Deep layer shear improves upstream near the base of the trough Sunday
afternoon in KY and/or TN, although not especially strong at 25-30 kt
in those areas. Not confident at this point there is sufficient flow
and overnight instability to expect organized convection to reach the
CWA Sunday night or early Monday.

Temperatures will trend warmer with the building ridge, in the lower
to mid 90s in the Piedmont and upper 80s in mountain valleys.
Although some diurnal mixing will limit afternoon dewpoints,
low-level moisture return will result in heat indices in the 100-105
range in warmer areas of the Piedmont each afternoon.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
As of 130 AM Fri: There remains spread in timing among models as to
the front. It looks questionable that the front will have induced
meaningful airmass change Monday, with Monday night more likely. A
signal for moisture pooling is seen on the GFS and EC Monday east of
the Appalachians, so PoPs remain elevated and generally similar to
Sunday. Shear and PWAT will be marginally better but the main
difference compared to previous days is that PoPs have a better shot
at continuing nocturnally given the frontal forcing tapering from
west to east behind the front. Temps "cool" back to around climo Tue
in the front`s wake.

The trough and frontal boundary, or their remnants, meet the Bermuda
High near the East Coast on Tuesday. The resulting convergence zone
appears to be a focus for convective development then through
Thursday. PoPs dip slightly Tuesday to about climo, then increase
again diurnally Wed and Thu with easterly to southeasterly flow as
the Bermuda High dominates, possibly bringing the convergence zone
inland and nearer our CWA, or simply supporting more daily
shower/storm development with the resultant moisture flux. Temps
however remain near or even slightly below climo owing to increased
cloud cover--but with muggy subtropical dewpoints.

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
At KCLT and elsewhere: Widespread IFR/LIFR low stratus and vsbys
have already overspread the terminals and will remain in place at
least through daybreak. Went with prevailing IFR/LIFR with TEMPOs
for the worst case scenario as much of the area remains locked in
with a stout low stratus deck and ground fog. Any low stratus and/or
fog will dissipate by mid-morning (14z or so) as daytime heating
helps to scatter out and lift restrictions. Light southwesterly to
variable winds will be in store through the morning hours and pick
up in speed (4-8 kts) out of the southwest by peak heating. KAVL
will maintain a north-northwesterly component through much of the
period. SCT cu is likely to roam the skies through much of the
afternoon and evening with another round of scattered to numerous
showers and thunderstorms. Placed a PROB30 for TSRA and associated
restrictions at all terminals as a result. Lingering convective
debris after sunset will leave mid-to upper-level clouds across the
area during the evening and early overnight hours. Another round of
low stratus and fog restrictions will be possible overnight tonight
through daybreak Saturday.

Outlook: Typical summertime weather is expected into early next
week, with scattered to numerous thunderstorms mainly in the
afternoon/evening and fog and/or low stratus possible each morning.

&&

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

&&

$$

SYNOPSIS...Wimberley
NEAR TERM...CAC
SHORT TERM...Wimberley
LONG TERM...Wimberley
AVIATION...CAC