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425
FXUS62 KGSP 110601
AFDGSP

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

.SYNOPSIS...
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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.
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&&

.NEAR TERM /THROUGH TONIGHT/...
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As of 150 AM EDT Friday: Most of the cloud debris from afternoon
and evening convection has drifted eastward within the prevailing
westerlies, allowing the area to clear with obvious tight dewpoint
depressions. This, to go along with relatively good coverage
of rainfall across the CFWA, expect widespread low stratus and
the potential for dense fog across a good portion of the area
underneath a weak nocturnal inversion through daybreak. A deck of
low stratus has already overspread the major mountain valleys and
the southern half of the CFWA. Expect this cloud deck to expand
northward through the overnight hours, while keeping overnight lows
near their current values. With that being said, overnight lows will
run at or slightly above normal. Any low stratus deck and lingering
fog should scatter out quickly after daybreak as low-level mixing
gets underway followed by summertime destabilization.

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. 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.
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&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
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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.
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&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
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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.
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&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
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At KCLT and elsewhere: Widespread IFR/LIFR low stratus has already
overspread the Upstate TAF sites and KAVL and will remain in place
at least through daybreak. Thinking is that this deck will expand to
KHKY and KCLT over the next couple of hours. With previous rainfall,
expect ground fog to become an issue as well with patchy dense fog
possible. Placed a TEMPO through 10z/11z for the initial low stratus
deck to expand across the terminals, followed by prevailing IFR/LIFR
cigs and vsby restrictions around 10z or after as everything settles
in place. Any low stratus and/or fog will dissipate by mid-morning
(13z 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. 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.
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&&

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

&&

$$

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