Area Forecast Discussion
Issued by NWS Greer, SC

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978
FXUS62 KGSP 151719
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
119 PM EDT Tue Jul 15 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 week.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
As of 110 PM EDT Tuesday: Another day of muggy weather and pop-up
convection as the southeast remains under broad flow aloft. A strong
Bermuda high remains parked over the Atlantic and moves a bit
westward, increasing moisture advection from the south. Not much
change in the amount of moisture already in the area as guidance
keeps PWATs at or just above the 2.00 inch mark. For today, another
round of the typical showers and thunderstorm activity starting over
the mountains and eventually making its way east. CAM guidance shows
more activity over the mountains with higher chances (55-80%),
especially over the ridgetops. East of the mountains, PoPs max out
in the 40-60% range during the typical peak heating time frame.
Given the amount of moisture with the higher PWATs, any storm that
can fire off has the potential to produce locally higher rain rates.
This could lead to an isolated and very local flash flooding threat.
Overnight, the PoPs continue to decrease, but cannot rule out a pop-
up shower or thunderstorm given the moist environment. There could
also be a few areas with low-level stratus developing near sunrise,
but should dissipate quickly after the sun comes up. For Wednesday,
the surface high continues to migrate further west, bringing more of
a S/SW surface winds and even more moisture advection. The location
of the high could help to direct activity into the areas of showers
and thunderstorms along the mountains. However, elsewhere also has a
chance (40-60%). Temperatures remain in the low 90s (mid 90s further
south) with the heat index increasing into the upper 90s. A few
locations in the southern zones could see HI of 100-103 today, but
remains below any Heat Advisory criteria.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
As of 1145 AM EDT Tuesday: The rest of the work week should
be more of the same...typical hot and humid summertime with
mainly diurnal storms both days...as a westward extension of
the Atlantic subtropical ridge keeps us insulated from whatever
happens with the system moving westward along/off the northern Gulf
Coast. The forecast will feature an above-climo precip probability
over the area, particularly the mountains, where differential
heating will provide a focus for convection. The usual isolated
pulse-severe storm threats will apply, and heavy rain could also
be a problem. Fcst soundings show deep warm cloud depths and
slow-moving storms, but the precipitable water will not be quite
as high as the past few days, so the flash flood potential looks
marginal for now. Temps will continue to run 3-5 degrees above
normal, but the apparent temps over the Piedmont should stay below
Advisory criteria Thursday and Friday.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
As of 1225 PM EDT Tuesday: The latest model blend suggests the big
story this weekend and into early next week will be the heat, as
part of the Atlantic subtropical ridge breaks off and moves slowly
west across the Deep South. In spite of nothing to suppress the
deep convection, temps will remain on the order of five degrees
above normal, while tropical moisture remains in place, keeping
the dewpoints in the lower 70s. This combination is forecast to
push the apparent temps up into the Advisory range each day from
Saturday onward across the lower Piedmont and the Charlotte metro
area/western Piedmont, even with mixing down the dewpoint from the
NBM by a couple of degrees. Note that none of this is out of the
ordinary for July. Confidence is marginal at this point anyway,
because there is much on the mesoscale that could derail this
potential, such as the weak upper wave moving past to our north
on Saturday and then a more active convective regime Sunday into
Tuesday as the upper high to our south oozes farther west and
flattens more, possibly bringing the MCS track farther south to
where it would affect the western Carolinas more directly. It`s
not until Monday/Tuesday when we keep precip chances going round
the clock, though, because of a better signal for something going
on aloft to sustain the convection overnight. Through the period,
pulse severe storms and isolated flash flooding will be possible
each day, which is also more or less typical for July.

&&

.AVIATION /17Z TUESDAY THROUGH SATURDAY/...
At KCLT and elsewhere: A mix of VFR and MVFR conditions through the
TAF period as the area remains in a typical summer pattern.
Increased moisture keeps lower SCT/BKN stratus around through most
of the period. With convection already popping up over the
mountains, will have a TEMPO at all sites except KAND for this
afternoon. Winds remain light and out of the SE and become VRB/calm
overnight. There is also the chance for another round of BR at
KAVL/KHKY during the morning hours. Heading into Wednesday, similar
pattern as today with TSRA chances toward the end of the TAF period
and a PROB30 at KCLT. Winds pick up later in the morning and turn
more southerly. There is a very low chance for a brief g15 at KCLT
in the afternoon, but will not prevail at this time due to low
confidence.

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...CP
NEAR TERM...CP
SHORT TERM...PM
LONG TERM...PM
AVIATION...CP