Area Forecast Discussion
Issued by NWS Greer, SC

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808
FXUS62 KGSP 141756
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
156 PM EDT Sat Jun 14 2025

.SYNOPSIS...
Seasonably warm and humid weather, with numerous showers and storms
each afternoon and evening, can be expected through Sunday. A
warming trend will begin on Monday, and daily showers and storms
will continue through most of the week.

&&

.NEAR TERM /THROUGH SUNDAY/...
Key Messages:

1) Isolated showers and thunderstorms possible late this evening

2) Warm and humid east of the mountains

3) Showers and thunderstorms during the afternoon and evening on
Sunday

As of 145 PM EDT Saturday: The CWA becomes caught in the middle of
two areas of high pressure, one over the southwest CONUS and the
other off the east coast. Meanwhile, the western edge of the Bermuda
high allows for a broad warm sector with an abundance of advected
moisture from the south, keeping the area locked into an unsettled
pattern. Synoptic forcing remains weak, but given the increased
PWATs and instability, should be more than enough to enact showers
and thunderstorms once again. The cloud cover plaguing the area
earlier have continued to scatter out, allowing plentiful sunshine
to reach the surface. Guidance from the CAMs suggest convection
minimal convection this afternoon. Though at this time of year, it`s
not uncommon for unreliable CAMs during more diurnally driven
convection. So cannot rule out a pop-up storm over the mountains
during peak heating. Through the evening and into the overnight
hours, shower and thunderstorm chances increase, mainly over the
mountains, as a shortwave passes above from the decaying upper low.
By Sunday, PoP chances increase again during the afternoon. So rinse
and repeat as the typical summertime pattern emerges. Isolated and
locally heavy rainfall possible with any developing storm.
Temperatures gradually warm into the upper 80s outside the mountains.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
As of 234 AM EDT Saturday...

Key Messages:

1) Afternoon showers and thunderstorms expected Sunday and Monday,
with low risk of severe weather.

2) Muggy and increasingly hot conditions expected early next week.

No major change to the thinking for the latter half of the weekend.
With a Bermuda High still in place across the western Atlantic,
diurnal showers and thunder are expecterd.  A deamplifying z500
trough axis will glide across the Ohio Valley on Sunday, providing
a modest uptick in synoptic forcing and lending a little extra
vigor to afternoon convection...with somewhat better coverage still
expected on Sunday compared to earlier in the weekend.  Lapse rates
still look less-than-favorable for severe weather...so sbCAPE will
struggle to creep above 1200 J/kg, and the bigger issue still looks
like isolated hydro issues where convection drives up rain rates.

On Monday, the Bermuda High will begin to retrograde
ever-so-slightly westward.  This doesn`t look like it`ll have
too much effect on the rain/thunder forecast through the end of
the short term...other than shifting the axis of best PWs a little
west of our CWA, and perhaps curtailing overall coverage courtesy of
weaker low-level moisture flux.  Nonetheless, ensembles depict solid
90th percentile PWs, especially across the NC mountains...so expect
another round of diurnal convection Monday.  And, as thicknesses
begin to increase, Monday should be the first day of what will
wind up being a weeklong warming trend...with highs expected to
be 1-2 categories above normal.

&&

.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
As of 256 AM EDT Saturday...

Key Messages:

1) Seasonal rain and thunder chances continue through Wednesday.

2) A weak cold front crosses the area Thursday night, resulting
in some limited drying.

3) Warming temperatures continue, and should be well above normal
Wednesday and beyond.

Unsettled weather will continue for much of the extended forecast
period.  Through at least Thursday, there`ll be little change in the
synoptic pattern...which is to say subtropical ridging will remain
in place and low-level moisture flux will continue, if perhaps
weakening Wednesday and beyond as the Bermuda High expands westward
and forces low-level winds to become more westerly.  Expect diurnal
showers and thunderstorms, with low-end severe risk...but at least
some concern for hydro issues...through Wednesday.

Wednesday night, a z500 trough will eject out of the northern
Great Plains, quickly crossing the Midwest and entering the
Ohio Valley on Thursday.  Operational guidance is in marginally
better agreement than earlier forecasts on the surface front`s
arrival in the Carolinas late Thursday evening or overnight...but
long-range ensemble solutions still depict significant variance in
timing...with some solutions bringing the front in early enough
Thursday for an elevated convective risk and others bringing it
in as late as the diurnal minimum Friday morning.

In any case, the front will bring in some slightly drier air, but
won`t be strong enough to really dislodge the Bermuda High...which
guidance depicts maintaining its strength if perhaps retreating
eastward a bit.  At best, it appears all we can expect is a lull
in afternoon showers for a day or so...and little if any relief
from unseasonably warm temperatures, which by the end of the period
may climb into the low- to mid-90s.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
At KCLT and elsewhere: Starting  off the TAF period with a mix
of VFR/MVFR conditions as lower stratus continues to clear out.
Confidence is low on the amount of TSRA this afternoon, hence a
PROB30 at all sites through this evening. There is a possibility for
some additional TSRA before midnight at a few locations. Will keep
VCTS for now. By daybreak, the amount of moisture in the area could
bring vsby/cigs down into the MVFR/IFR, especially at KAVL, before
12z. It doesn`t look as widespread as previous days, but lower
stratus is still possible briefly for most sites affecting cigs.
Slow improvements during the morning hours as the lower cloud deck
clears out once again. Then, rinse and repeat as another round of
pop-up TSRA is expected across all sites Sunday afternoon. Winds are
expected to remain S/SW and relatively light.

Outlook: Showers and thunderstorms are expected each day through
early next week. Late night and early morning fog and low stratus
restrictions each day.

&&

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

&&

$$

SYNOPSIS...JMP
NEAR TERM...CP
SHORT TERM...MPR
LONG TERM...MPR
AVIATION...CP