678
FXUS62 KGSP 291007
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
607 AM EDT Sun Jun 29 2025

.SYNOPSIS...
A typical summer pattern continues into early next week with
seasonable temperatures and daily chances for afternoon and early
evening thunderstorms. A cold front approaches the area on Tuesday
and drier weather may return for the holiday weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 535 AM EDT Sunday: Nothing much to update at this time. The
skies are mostly clear across the area with the typical mountain
valley fog in full swing. Forecast is on track.

Otherwise, the region remains under broad flow and the typical
summertime pattern continues. The strong surface high off the
eastern coastline amplifies westward, increasing moisture return
from the south. Guidance shows an uptick in PWATs through the period
into the 1.5-1.75 range, especially east of the mountains. By
tonight, dewpoints look to increase into the low 70s, bringing a bit
more of the muggy feel. Meanwhile overnight, a few areas could see
some patchy low-level stratus or fog near daybreak, mostly confined
to the mountain valleys. If any should develop, expect it to clear
after daybreak. As for Sunday, the area remains in general thunder
from the Storm Prediction Center as another round of afternoon pop-
up convection ensues. A bit of a surface shortwave is expected to
meander through the southeast, which could provide additional lift
to the more typical diurnally driven storms. However, the steering
flow is nonexistent as winds aloft are extremely weak to calm. Once
again an inverted-V on modeled soundings show an environment capable
of rapid evaporative cooling. This is apparent with dCAPE values
nearing 1000 J/kg, increasing the chances for strong winds out of
developing downbursts. Cannot rule out a severe storm, but it would
mainly be for winds. Most of the storms should weaken into Sunday
evening as peak heating ceases. Depending on what areas can get
rain, there is a chance for some more low-level stratus and patchy
fog again tonight, especially in the mountain valleys. As far as
temperatures, low 90s east of the mountains and overnight lows
dipping into the low 70s.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
As of 300 am Sunday: A weakness in the subtropical ridge
covering the Southeast will evolve into more of a trough during
the short term, as heights fall in response to a series of
short wave troughs traversing the northeast Conus and southeast
Canada. With southerly flow around a Bermuda high supplying plenty
of moisture...precipitable water values of around 1.75"...and
strong insolation allowing the atmosphere to destabilize to
the tune of 2000-3000 J/kg each day...conditions will remain
favorable for diurnal convective development...with likely PoPs
warranted across the mountains and 40-50% chances elsewhere Monday
afternoon. Convective chances will be further enhanced Tuesday,
as low-level boundary moves into the area in association with
height falls, and 70-90 PoPs are warranted across the entire CWA
during the afternoon and evening. Similar to the last couple of
days...a few pulse severe storms will be possible on Monday, with
locally heavy/isolated excessive rainfall also possible in light
of continued slow cell movement. Deep layer shear is forecast to
increase to around 20 kts on Tuesday, so some degree of modest
organization/clustering along outflows will become possible, which
combined with overall higher coverage will yield an uptick in
the severe storm potential. Although cell movement will increase
Tuesday, high moisture content will continue to produce some
threat for isolated excessive rainfall. Temperatures will remain
slightly above normal and min temps several degrees warmer than
climo through the period.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 315 am Sunday: Upper trough axis and associated low level
boundary will gradually become established E=>S of the forecast
area early in the extended...allowing lower theta-E/drier air
to gradually filter into the region during the latter half of
the week. Sufficient moisture and instability should linger on
Wednesday to support scattered convection...especially across the
southern zones and portions of the Blue Ridge. With drier/less
unstable air settling over the area, the remainder of the week is
expected to see below-normal coverage of diurnal convection...with
general 20-30 PoPs advertised over the mountains...and 10-20%
chances elsewhere each afternoon Thu through Sat. Temps are mostly
forecast at 1-2 degrees above climo through the period.

&&

.AVIATION /10Z SUNDAY THROUGH THURSDAY/...
At KCLT and elsewhere: VFR conditions prevail through the TAF period
at most sites. Similar to the last few days, calm to light VRB winds
pick up again gently later this morning. High pressure off to the
west of the area allows for more southerly winds Sunday afternoon,
but still remain light. By Sunday afternoon, another chance for
scattered showers and TSRA, possible anywhere especially in the
mountains. Chances are higher for the mountains so will add a TEMPO
at KAVL and HKY, with PROB30s elsewhere. Once showers and
thunderstorms clear up, another calm night ahead. Depending on
whether or not the mountain sites can receive any rain, will greatly
impact the BR/FG chances before the end of the TAF period.

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...CP
NEAR TERM...CP
SHORT TERM...JDL
LONG TERM...JDL
AVIATION...CP