739
FXUS62 KGSP 160605
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
205 AM EDT Wed Jul 16 2025

.SYNOPSIS...
Daily thunderstorm chances continue through the week and into the
weekend. A few storms could produce damaging wind gusts and
localized flash flooding. Hot and humid conditions stick around
through most of the forecast period.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 1245 AM Wed: Southerly flow regime continues across the
CWA. Despite rather poor lapse rates owing to the deep subtropical
moisture over the area, convection has continued to fire along the
south and southeast facing slopes of the Blue Ridge Escarpment
where terrain is enhancing lift. A few spots have reported
rain rates/accumulations of up to 1 inch in an hour. So far the
low-level southerly winds are providing enough steering flow to
keep storms moving, but possible training or anchoring in these
terrain areas could result in localized minor flooding. Most CAMs
depict coverage slowly diminishing as we approach daybreak. Patchy
low stratus looks to develop in areas that saw rain in the evening
or early morning, and via moisture advection on the southerly flow.

The early morning convection appears to work over the Escarpment
such that convection will be suppressed through midday there,
but farther north near the TN border LCLs will be low and showers
may fire soon after daybreak where the upslope flow continues, but
that too may be short-lived. Otherwise, today looks to be closer
to a typical midsummer setup for the Carolinas/Georgia as moist
southerly flow continues, with PWATs remaining in the 1.8 to 2
inch range. Influence of low pressure near the FL Panhandle should
diminish, with flow remaining southerly as opposed to southeasterly
as yesterday; the Bermuda High dominates, and coverage appears
lesser overall. Modest instability is re-established by midday and
ridgetop initiation appears possible again by early afternoon,
supporting near-climo PoPs, mostly 40-50%. A weak capping layer
persists in prog soundings over much of the Piedmont which will
keep initiation isolated there, but models mostly feature better
coverage in the slightly more favorable environment in the CSRA
and Midlands to our south which could propagate north, so low
chance PoPs are retained for our southeastern zones. Max temps
near normal with higher than typical dewpoints as a result of the
subtropical moisture and limited mixing, so some areas may exceed
100 heat index.

Some CAMs, and seemingly the NAM, depict evening convection
propagating into our southern zones along sea breeze, or an outflow
boundary from South Georgia. Similar to this morning, a nocturnal
inversion appears slow to form and such activity can`t be ruled out,
nor can a few isolated cells developing on south-facing slopes,
so we retain small PoPs much of the night, slowly diminishing by
early Thu morning.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
As of 125 AM EDT Wednesday: Bermuda ridge will gradually expand
westward during the period, while steady west to southwesterly flow
filters in continuous hot and humid conditions. A slight uptick in
temperatures and heat index values are evident with muggy dewpoints
and warmer thicknesses in place. Diurnal convection will continue
through the end of the workweek, especially in the mountains
where above climo PoPs are expected. Trends in PWAT values have
lowered, likely being choked off by the tropical disturbance over
the Gulf. This helps to lower the overall hydro threat, but there
will still be the concern of a few instances of localized flash
flooding to go along with the wet microburst threat. Temperatures
will continue to run a category or so above normal, with heat
indices in the low 100s across the Piedmont Thursday and Friday
and only flirting with Advisory criteria by Friday.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 145 AM EDT Wednesday: The aforementioned extension of the
Bermuda ridge will set up shop over the southeastern CONUS by this
weekend into early next week. Ambient temperatures are likely to
be a few ticks higher compared to the short term for this weekend
into early next week as a result. Dewpoints remain elevated as well,
which could combine for a better chance for Advisory criteria heat
indices, especially in the Charlotte metro and Lower Piedmont. As
the ridge continues its westward push further into the Deep
South and Lower Mississippi Valley early next week, the flow aloft
flattens out a bit and turns more west to northwesterly and places
a somewhat favorably track for MCSs to push further south into
the CFWA. This will be a trend to keep an eye on, but either way
the day to day pulse convection and localized flash flood threat
will be in play each day in mid-July fashion unless interrupted
by said MCS potential. The forecast mostly remains the same each
day through D7 (wash, rinse, repeat).

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
At KCLT and elsewhere: SHRA and isolated TSRA continue at issuance
time along the Blue Ridge Escarpment, south of KAVL and NW of
KHKY/KGSP/KGMU/KAND. That activity should slowly diminish during the
predawn hours. KAVL and KHKY received some rain since sunset and
given otherwise moist conditions TEMPOs for daybreak restrictions
are included. At KCLT and the SC sites, nocturnal stratus appears
likely and prevailing MVFR to IFR cigs were warranted. Winds
southerly when not VRB early this AM. Low LCLs imply FEW-SCT cu
at MVFR level will be seen in the early part of the day. Winds
remain S to SSW today. Fairly typical, mainly afternoon and early
evening PROB30s for TSRA at all sites. Convective debris or spotty
low VFR cu will be seen tonight. Not confident enough to include
any mention of stratus at KCLT early Thu, with any restrictions
elsewhere likely not seen until after 06z.

Outlook: Thunderstorm chances each afternoon/evening. Low stratus
or fog are possible each morning in mountain/river valleys.

&&

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

&&

$$

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