543
FXUS62 KGSP 072358
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
758 PM EDT Mon Jul 7 2025

.SYNOPSIS...
Hot and humid conditions continue through midweek featuring daily
afternoon and evening shower and thunderstorm chances. The heat
abates somewhat into the weekend but daily afternoon and evening
shower and thunderstorm chances continue.

&&

.NEAR TERM /THROUGH TUESDAY/...
As of 736 PM Mon: A few showers and storms were making the
most of the environment to the south and west of the Charlotte
metro area early this evening, where a relative CAPE minimum was
located. Nevertheless...there they are. Will add in a small chance
of showers for the next hour or two until sunset, when the shower
activity should be dissipated. Temps were in good shape.

Otherwise...as post-TC Chantal moves up the mid-Atlantic coast
thru the evening, it is progged to be absorbed into a weak sfc
low centered in Ontario. A subtle cold front extends southwest
from the aforementioned sfc low into the mid-Mississippi Valley. A
trough moving across the northern Plains will help push the frontal
features slowly eastward by Tuesday. A sfc trough looks to remain
east of the Appalachians. While the front itself remains to our
west through peak heating Tue aftn, some degree of moisture pooling
ahead of it leads to higher PWATs and more midlevel moisture, both
of which make profiles more favorable for deep convection. The rest
of the pattern remains pretty similar to today. PoPs accordingly
tick upward such that 40-60% PoPs will be advertised over the
mountains, decreasing to 20-30% over the Piedmont. SPC continues
to highlight our eastern zones in Marginal Risk for damaging wind
on account of wet microburst potential associated with heavy water
loading and 2000+ SBCAPE in the afternoon. It could be argued the
severe potential will extend across more of the CWA, although such
storms are likely to remain isolated, and marginal-level risk is
appropriate. Temps will rise slightly warmer into the upper 90s
across much of the Piedmont, but thinking is that aftn mixing still
will bring dewpoints low enough to limit heat index to 100-104 in
most locations, so Heat Advisory does not look warranted.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
As of 200 PM Monday: A shortwave will propagate into the OH and TN
valleys on Wednesday, resulting in height falls over our area and
slightly lower thicknesses.  Its proximity will enhance forcing
across the area as diurnal heating supports SBCAPE of 1000-2000
J/kg.  Categorical PoPs exceeding 75-80% are forecasted across
the mountains and NC Piedmont, with likely PoPs of 60-75% over
much of Upstate SC and the GA Piedmont, where profile guidance
suggests a deeper mixed layer, higher LCLs, and subsequently
lower surface-based instability.  Bulk-shear values increase
slightly ahead of the trough but generally speaking, values are
not supportive of organized convection.  However, profile guidance
suggests that there will be sufficient mid- and upper-level dry
air to support isolated damaging microbursts.  PWs of 1.6-1.8"
and fairly unidirectional low- and mid-level flow support some
cell training capable of producing isolated areas of excessive
rainfall.  The suppression of the subtropical ridge and increased
cloud cover should reduce high temperatures a few degrees, though
most areas will likely peak at slightly above-normal temperatures
even if rain-cooled outflow arrives later in the afternoon.  While
afternoon mixing is expected to lower dewpoints a few degrees in
the afternoon, heat indices will likely approach the 100-103 range
in favored areas of the Savannah River Valley and the CLT metro.

With strong subtropical ridging in place over the Sargasso
Sea/western Atlantic and shortwave ridging over the Great Lakes,
there will be little eastward progression or deamplification of
the shortwave trough located just to our west over the TN Valley.
As such, expect similar unsettled weather and convective coverage
Thursday afternoon and evening.  Increasing moisture through the
column given persistent SWly flow and favorable storm-motion vectors
suggest a continued risk for isolated areas of excessive rainfall.
Bulk-shear values increase a bit further, approaching 20kts,
and despite tall and skinny CAPE profiles, a wet microburst
threat will continue where the strongest updrafts can develop.
High temperatures will fall a few degrees further compared to
Wednesday given thicknesses, cloud-cover, and convective coverage,
but this will only equate to highs near normal for mid-July.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 200 PM Monday: The extended period will remain active as
we are generally sandwiched between subtropical ridging along the
Gulf Coast and the southern extent of the westerlies, which will
usher in rounds of weak shortwaves across the OH and TN valleys
and over the central and southern Appalachians through the period.
This pattern will support likely to categorical PoPs over the
mountains and foothills with chance PoPs over the Piedmont each
afternoon and evening.  Low-level moisture will continue to pool
across the area with flow taking a circuitous route from the western
Gulf of America, around the persistent Gulf Coast ridge, and into
the southern Appalachians; therefore, typical periods of heavy
rainfall can be expected, with isolated areas of excessive rainfall
possible.  Parameters are not supportive of a notable severe
weather threat any afternoon, with the typical isolated damaging
wet microburst being the primary concern.  High temperatures will
also remain fairly stable at near-normal values, with upper 80s
in the mountain valleys and lower 90s across much of the Piedmont.
Overall, pretty typical July weather is expected.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
At KCLT and elsewhere: Isolated showers and thunderstorms continue
across the region at issuance time, but for the most part too
far away from the terminals to include in the forecast. After the
shower activity diminishes at sunset, should be a quiet night with
only light/variable wind and some thin cirrus overhead. Mtn valley
fog is not expected. On Tuesday, some moisture pooling along a
boundary will allow for better coverage of thunderstorms in the late
afternoon and early evening. Will handle this with a generic PROB30
at all sites other than KAND. Wind should be light SW and clouds
limited to scattered cu with high bases, apart from thunderstorms.

Outlook: Typical summertime weather is expected thru late week,
with sct to numerous SHRA/TSRA mainly in the aftn/evening and fog
and/or low stratus possible each morning.

&&

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

&&

$$

SYNOPSIS...JMP
NEAR TERM...PM/Wimberley
SHORT TERM...JMP
LONG TERM...JMP
AVIATION...PM