Greenville, South Carolina 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

882
FXUS62 KGSP 151742
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
142 PM EDT Fri Aug 15 2025

.SYNOPSIS...
Afternoon showers and storms develop again today and tomorrow,
before drier and warmer conditions arrive Sunday and early
next week.  By mid- to late-week, temperatures cool off again,
and afternoon convection returns.

&&

.NEAR TERM /THROUGH SATURDAY/...
As of 1226 PM Friday: Convective initiation has taken place
across the ridges as of midday, more or less as expected, while
the convection looks suppressed east of the Blue Ridge. The
sfc-based CAPE was on the order of 2000-3000 J/kg at noon, but
might drop a bit as our dewpoints mix out somewhat. The risk of
severe storms looks minimal as we lack dCAPE. The sfc analysis
shows a weak boundary pushing southward across the region, but it
doesn`t seem to be making much of a difference yet, but it stands
to reason that our potential for heavy rain should take a downward
tick. Temp trends look good and highs are still expected to be a
bit higher than yesterday, but the apparent temp should stay below
Advisory criteria.

For the afternoon, the CAMs show the mtn convection gradually
building and then moving off the Escarpment in the mid/late
afternoon, but with a concentration over the srn mountains,
northeast Georgia, and the western Upstate, presumably because
of the location of the old boundary. There`s a wide range in
coverage between the aggressive NSSL WRF/FV3 and the more muted
HRRR. Either way, the NW Piedmont looks to be the quietest and
the northeast GA mountains the busiest. The precip probs have
been modified accordingly. The convection should diminish in the
mid evening as we lose heating. The rest of the night should be
quiet. Convective debris clouds are expected to thin out enough
to allow for another late night of mtn valley fog. Low temps will
stay a deg or two above normal.

The eastward drift of Plains mid/upper anticyclone tonight into
Saturday will generally be more suppressive of convection for
Saturday afternoon, and the environment will be less unstable. The
guidance suggests a day with precip probs on the dry side of climo
with most of the action over the mountains, which is supported by
the morning runs of the CAMs. Again, the risk of severe weather
looks minimal. Temps will be right around normal.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
As of 101 PM EDT Friday...

Key Messages:

1) Convection will be suppressed on Sunday and Monday by broad
high pressure developing over the eastern CONUS.  Some ridgetop
showers and storms will be possible each afternoon.

2) Temperatures will creep a category or two above normal each
afternoon.  Monday will be the hotter of the two days.

The subtropical ridge will remain the dominant feature impacting
our forecast area for the duration of the short term period.
Though its core will be centered over the Ozark Plateau, a
significant portion of its eastern periphery will extend into the
Southeast and Ohio Valley, resulting in warmer thicknesses and
an intermittent stream of moisture and shortwave energy dipping
down out of the Great Lakes region.  Low-level flow, meanwhile,
will come from the northeast...as what would otherwise be SE flow
off the Bermuda high is disrupted by a weak coastal low offshore
of the NC Outer Banks.

For the Carolinas, the latest 12z suite of operational guidance
supports mostly dry conditions on Sunday, when subsidence will
be strong enough to mostly cap developing convection despite some
1500+ J/kg sbCAPE.  Some ridgetop showers and storms are certainly
possible, but coverage over the low terrain is in question.  Similar
conditions are expected Monday, with weakly suppressed profiles
that will somewhat inhibit convective initiation.  Once again,
guidance depicts mostly ridgetop convection.  There are also hints
in some GEFS ensemble members of a weak convergence axis developing
Monday afternoon somewhere in the eastern Upstate or Midlands, which
could help overcome subsidence and tap into what instability exists.
So, confidence is low, but there`s a conditional chance of thunder
outside the mountains Monday.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
As of 114 PM EDT Friday...

Key Messages:

1) Less shower and storm activity is expected the first half of
the week.

2) Temperatures will drop sharply on Tuesday, remaining near or
below normal through the end of the week.

3) No impacts are expected this week from the passage of Hurricane
Erin, which will remain well east of our forecast area off the
Atlantic Coast.

By Tuesday, the regime will be on the cusp of changing, as upper
anticyclonic flow intensifies but becomes centered farther west,
over the Four Corners region; a broad and deep 500mb trough axis
will intensify over east-central Canada and dip into the Ohio
Valley by late Tuesday.  Operational guidance depicts a shortwave
sharpening up over Kentucky and the Virginia Blue Ridge Tuesday
night into Wednesday in response...which greatly amplifies the
amount of synoptic forcing available for the Carolinas...but
ultimately may not be enough to prompt more than isolated to widely
scattered diurnal convection...as the low-level flow will remain
out of the northeat, influenced by the circulation Tropical Storm
Erin passing well off the coast of the Carolinas.  To be clear:
no impacts from Erin are expected over the western Carolinas and
northeast Georgia.

In any case, the aforementioned trough will phase with Erin`s
upper trough and steer the system out to sea, allowing us to
return to a more typical synoptic setup Thursday and beyond.
SW flow will be featured at the low-levels, advecting in better
moisture and permitting a return to diurnal showers and storms on
Thursday and Friday.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
At KCLT and elsewhere: Convection has already developed over
the ridgetops early this afternoon, so the immediate concern
will be thunderstorms around KAVL. Opted for a TEMPO because of
the proximity to convection already, even though confidence not
necessarily at 50pct. The CAMS suggest that the other terminals
might get a storm in the late afternoon or early evening, but
confidence is no better than 30 pct and restrictions are included
therein. Otherwise, prevailing VFR. That brings us to KCLT and
the downward trend in coverage seen in the morning runs of the
HRRR. Confidence not high enough to keep in the PROB30 from
the earlier issuance, so it was pulled. Places east of the mtns
could have a temporary VFR bkn cu ceiling through late afternoon,
otherwise a light NE wind. The convection should diminish with
loss of heating around sunset, then just dissipating convective
debris clouds. Looks like a good setup for mtn valley fog/stratus
in the early morning hours Saturday, and would not be surprised by
IFR/LIFR/brief VLIFR restrictions at KAVL, but will take it down
only as low as LIFR at this time. KHKY could also get some fog off
the lake. For Saturday, looks even more quiet than today, so only
scattered stratocu by the end of the period with more light NE wind.

Outlook: Afternoon showers and thunderstorms with associated
restrictions are expected mainly across the mtns through the
early part of the next week.  Morning fog and low stratus are also
possible, especially across the mountain valleys.

&&

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

&&

$$

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