Clemson, South Carolina 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

340
FXUS62 KGSP 191027
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
627 AM EDT Sat Jul 19 2025

.SYNOPSIS...
Daily mainly afternoon and evening shower and thunderstorm chances
continue through early next week. A few storms could produce
damaging wind gusts and localized flash flooding each day. A weak
cold front slowly crosses the area from the north Monday night
into Tuesday. High pressure moving in from the north behind this
front will temporarily bring temperatures closer to normal during
the middle part of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 1229 AM Saturday: Upper ridging centered just off the
southeast coast will slowly retrograde today across the Florida
peninsula and towards the eastern Gulf. Influence from the ridge
will extend from the Southern Plains across the Carolinas and
southeast states. Farther north, a belt of westerlies remains draped
along the Canadian border. Weak westerlies will extend across the
Southern Appalachians with several ripples in the flow noted on
early morning water vapor imagery. The forecast will be fairly
similar to yesterday with scattered to numerous diurnal
thunderstorms initiating across the mountains. Slightly strong flow
should allow for greater coverage east of the mountains across North
Carolina with convection potentially making it as far east as the I-
77 corridor. To the south along and south of I-85 across northeast
Georgia and the Upstate coverage is expected to remain isolated to
widely scattered as this area will remain displaced from the better
flow to the north and under greater influence from the upper ridge.
As with any summer convection, a few strong storms capable of wet
microbursts will be possible and a stray severe storm or two cannot
be ruled out, mainly along and north of the I-40 corridor where deep-
layer vertical wind shear will peak around 20kts. A lack of DCAPE
and poor lapse rates will generally preclude a greater threat for
damaging winds. A very moist airmass will also remain in place with
efficient rainfall rates likely. Any location that sees a quick 2-4"
of rain will have the potential for localized flash flooding. A few
storms may linger into the late evening but most activity should
wane by midnight with another round of mountain valley fog again
tonight. Temperatures today will once again climb into the low to
mid 90s, but dewpoints mixing into the upper 60s should limit
coverage of advisory level heat indices. The most likely location to
see advisory criteria will be across the Charlotte metro where a heat
advisory has been continued.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
As of 1259 AM EDT Saturday: All indications are that our stretch
of hot and humid summer weather will persist into the early part
of next week, even as the overall pattern slowly evolves from an
upper anticyclone over the Southeast Sunday to a building mid/upper
ridge over the MS Valley and a trof off the East Coast by Monday
night. Confidence is fairly high in the high temps being five
degrees above normal on Sunday and high enough dewpoints to push
the apparent temp near Heat Advisory criteria in the afternoon. One
should anticipate another Advisory for at least the Charlotte metro
area if there are no changes. Convection probably won`t save us
as precip probs look to be around climo. The GFS in particular
suggests a relatively quiet day with dnva aloft that would keep
the environment less than favorable. However, Monday could be
more active as the upper pattern amplifies and brings a short wave
down from the NW during peak heating. Precip probs will be above
climo and linger into the overnight hours based on the timing of
the wave passage. The usual chances for pulse severe storms with
heavy rain will be there both days, but the environment might be
more favorable to our north and west. Temps will once again top
out well into the 90s with another Heat Advisory possible.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 110 AM EDT Saturday: The middle part of the week still looks
most interesting in this stretch as a weak backdoor cold front
drops across the region Monday night and the upper pattern briefly
supports sfc high pressure moving past to our north Tuesday into
Wednesday. The guidance has trended toward relocating the center of
a mid/upper anticyclone to the Mid-MS/lower OH Valley regions for
Tuesday and Wednesday, and in doing so, support a stronger sfc high
that sticks around long enough and with enough cool/dry advection to
suggest a full-on summertime wedge for both days. We will approach
this development cautiously in an attempt to not wish-cast some
cooler weather, but it is worth mentioning that a majority of the
model solutions are cooler than what the NBM shows for both days,
giving us a good chance at bringing temps back down to normal or
a few degrees below for highs, bringing an end to our streak of
90+ F days. Which would be nice. There is much uncertainty with
the precip probs on Tuesday, with some of the guidance keeping
the backdoor front around with an easterly upslope moisture flow
forcing relatively high precip probs, but other guidance members
bringing in more dry air earlier in the day and limiting precip
to the mtns. By Wednesday, the drier easterly flow wins out and
precip probs drop below climo. Alas, the more normal temps will
not last, and the NBM has us right back to the mid/upper 90s by
this time next week as the upper ridge elongates to the north
of our area. The GFS solution is discounted for the time being,
but considering how much spread there appears to be in the model
solutions, confidence is low. Either way, it`s still July, so it
will very likely be a return to diurnal storms.

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
At KCLT and elsewhere: VFR conditions will prevail through the
morning with only spotty mountain valley fog, mainly west of KAVL.
Thereafter, the main focus will be thunderstorms this
afternoon/evening. Coverage is expected to be the greatest across
the mountains and into the foothills along the I-40 corridor. TEMPOs
have been carried at KAVL and KHKY where confidence is highest.
Farther south, towards I-85, coverage remains a little more
uncertain. KCLT will be close to the action and the PROB30 may need
to be converted to a TEMPO with later TAF issuances. The Upstate
terminals (KAND/KGMU/KGSP) have the lowest confidence and PROB30s
will be maintained. Another round of mountain valley fog will be
possible overnight with impacts not out of the question at KAVL.

Outlook: Daily thunderstorm chances will continue through early next
week each afternoon and evening. Low stratus and/or fog are possible
each morning, especially across the mountain valleys.

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...Heat Advisory from noon today to 8 PM EDT this evening for
     NCZ071-072-082.
SC...None.

&&

$$

SYNOPSIS...PM
NEAR TERM...TW
SHORT TERM...PM
LONG TERM...PM
AVIATION...TW