132
FXUS62 KGSP 271739
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
139 PM EDT Fri Jun 27 2025

.SYNOPSIS...
Temperatures are forecast to be near or slightly above normal
through the the first half of next week. Expect afternoon and
evening showers and thunderstorms each day.  A weak cold front may
reach our region by Tuesday then drift south of our area through mid
week.

&&

.NEAR TERM /THROUGH SATURDAY/...
As of 135 PM EDT Friday: Ridgetop convection has started. Expect the
convection to remain limited to the mountains early this afternoon
then develop across the foothills and Piedmont by late afternoon.
The atmos is very unstable with high DCAPE values and little to no
bulk shear. Expect a few storms to become tall enough to entrain the
mid level dry air and become severe with damaging wind gusts and
possibly large hail. That said, CAM guidance suggests coverage of
storms will be lower than Thu but favoring the mountains. Some
suggest convection lingering later in the evening, but have kept
trends to near normal diurnal timing for now. Steering currents look
to be from the SE which could lead to some training of cells or
anchoring along SE facing ridges. Therefore, isolated flooding can`t
be rule out.

Expect another round of mountain valley fog overnight with some fog
possible near lakes and rivers, or locations with heavy rainfall.
Lows will be near normal for the mountains and a few degrees above
normal elsewhere.

Heights are slightly lower Saturday as a weak upper low moves north
into the western Carolinas. The atmos becomes very unstable again
with slightly better shear. DCAPE and sfc delta theta-e are not as
high as previous days, but not zero. Therefore, the overall threat
of severe storms is lower, but an isolated damaging downburst is
possible. PW values remain high with SE steering flow again which
keeps a low end threat of training of cells or anchoring along SE
facing ridges. Isolated flooding can`t be rule out. Highs will be
near normal for the mountains and a few degrees above normal
elsewhere.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
As of 1215 PM Friday: The forecast continues tomorrow night into
Sunday with a broad Bermuda high just off the east coast and
broad/flat upper ridging extending across the southern CONUS. More
active northern stream flow will be displaced north along the
Canadian border where a trough will be sliding across the Northern
Plains and into the Great Lakes region. A warm and humid airmass
will remain entrenched across the Southern Appalachians with
favorable conditions for above average coverage of diurnal
thunderstorms both Sunday and Monday. Coverage may tick higher on
Monday as the trough drops towards the Ohio Valley and heights
gradually lower. As with any summertime convection, locally heavy
rainfall and a few wet microbursts will be possible with any strong
storms. Steering flow will be weak as well with very slow moving
storms that could pose a threat for isolated flash flooding should
several inches of rain quickly accumulate. Temperatures will remain
seasonable.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
As of 1231 PM Friday: Previously mentioned trough will swing across
the Ohio Valley and into New England on Tuesday with the trough axis
also passing through the Appalachians. An attendant surface cold
front will also drop towards the area which will help support the
greatest rain chances of the period. Numerous to widespread
thunderstorms are expected as the front moves into the area during
peak heating on Tuesday. Flow remains weak, however, but at least
loosely organized convective clusters/linear segments should be able
to organize along composite cold pools. Thereafter, forecast
confidence begins to lower by mid to late next week as guidance
diverges with regards to how far south the frontal boundary makes
it. Drier air behind the boundary would result in a notable
downtrend in diurnal convection with just isolated potential. Should
the front stall across or near the area, however, above average rain
chances could continue. Will keep at least a slight chance for
convection in the forecast until guidance comes into better
agreement.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
At KCLT and elsewhere: VFR conditions expected for most terminals
through the TAF period. Convection already started near KAVL, so
TEMPO for them. Convection possible elsewhere, KHKY has the better
chance so a longer PROB30 there than the rest of the sites. Some
guidance showing convection lingering into the evening, but kept
times near diurnal norms for now. SW wind this afternoon, NW or
variable at KAVL, becomes light and variable overnight. Expect
another round of mountain valley fog, so have gone persistence with
IFR vsby there, but LIFR vsby and cigs possible. SW winds pick back
up during the day Saturday with diurnal convection again.

Outlook: Daily chances for afternoon and evening showers and
thunderstorms into next week. Fog and/or low stratus possible each
morning in the usual mountain valleys as well as near lakes and
rivers.

&&

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

&&

$$

SYNOPSIS...DEO
NEAR TERM...RWH
SHORT TERM...TW
LONG TERM...TW
AVIATION...RWH