Clemson, South Carolina 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

630
FXUS62 KGSP 251324
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
924 AM EDT Wed Mar 25 2026

.WHAT HAS CHANGED...
No major changes to forecast thinking over the next week.

&&

.KEY MESSAGES...
1. Low-impact weather expected through late in the week, with a
steady warming trend continuing through Thursday night.
2. Record high temperatures possible Friday ahead of another
cold front. The front brings a chance of showers late Friday and
Friday night.
3. Cool, dry high pressure builds in for the weekend with
moderating temps early next week.

&&

.DISCUSSION...
Key message 1: Low-impact weather expected through late in the week,
with a steady warming trend continuing through Thursday night.

Not much to write home about for the next couple days. The synoptic
pattern right now is dominated by deep subtropical ridging over the
Desert Southwest and northern Mexico, which is essentially acting as
a large-scale block, deflecting would-be Rossby waves to the north
so that they only skirt our northern zones.  One of these waves, a
low-amplitude shortwave axis barely discernible on water vapor
imagery, is responsible for ongoing cloud cover and should drift
east of I-77 by mid-morning today, allowing cloud cover to briefly
diminish.  Another weak embedded shortwave will drift across the Mid-
Atlantic this evening, prompting additional mid-and high-level
clouds to develop Wednesday night.  As the high drifts farther
offshore during this time, whatever weak surface CAA is in place
will cease...giving way to gradually-intensifying low-level
WAA...and allowing a steady influx of low-level moisture.  So, after
several days of enhanced fire danger, the window for issues is
likely over through at least Thursday...and increasingly moist
conditions are expected each day.

Temperatures through the period reflect this setup.  Today`s highs
should hover around normal in most locations, but by Thursday temps
will creep 2-3 categories above normal...and low temperatures may
flirt with records by Thursday night.  By Friday morning, a cold
front will ooze across the upper Ohio Valley...and winds will start
to pick up...but the front should not make it to us before daybreak
Friday.


Key message 2: Record high temperatures possible Friday ahead of
another cold front. The front brings a chance of showers late Friday
and Friday night.

As strong high pressure expands out of Canada and the northern
Plains Friday, a zonally oriented cold front will push through the
Southern states, from west Texas to the Tidewater region. Prior
to the front our region will be under the very broad upper ridge
centered over the Mexican Plateau, characterized by heights and
temperatures at 850, 700, and 500mb being above the 95th percentile
for late March; owing to the breadth of the ridge flow at those
levels will be predominantly westerly. Lapse rates look to be poor
in the low levels The front still looks to arrive late enough in the
day Friday that skies will be mostly sunny, and the exceptionally
warm airmass and possibly some downsloping lead to max temps which
will threaten the daily records at CLT and GSP that day.

Moisture return will be limited owing to the westerly flow ahead
of the front, but PWATs still are progged to become anomalously
high. The front initially will have very little in the way of
dynamic support, with the jet and primary trough axis being
kept across the northern states by the ridge, but there will be
respectable frontogenetic response owing to the strong thermal
gradient across it. Profiles do appear likely to saturate along/west
of the Appalachians, and low-level lift appears sufficient to
warrant likely PoPs near the TN border Friday afternoon. Lapse
rates will be weak and thunder chances are too small to mention
in the forecast at that time/area. In the lee of the mountains,
vertical profiles feature only marginally supportive lapse
rates atop what looks to be a deeply mixed boundary layer late
Fri afternoon and evening, though dynamic lift eventually should
increase there as the trough amplifies slightly over the CWA once
the front passes the mountains. Slight-chance to chance PoPs do
result for the foothills areas; the best overall chance outside
the mountains is in the I-77 corridor Friday evening ahead of the
trough axis. Still not seeing enough viable instability to warrant
a thunder mention. Owing to the weak forcing and instability, it
continues to look like this front is unlikely to bring meaningful
rainfall to the area, particularly east of the Appalachian spine;
NBM probs of 0.25" 48-hr rainfall ending Saturday morning are no
better than 20% in the NW NC Piedmont, and increasingly low as
one heads south from there.


Key message 3: Cool, dry high pressure builds in for the weekend
with moderating temps early next week.

The Canadian high will build into the area Saturday; winds look
to remain breezy with some gusts possible during the morning,
but those trend lower by afternoon. Temperatures should top out
a few degrees below normal. Dewpoints look to fall into the teens
or lower by afternoon, although mixing will be limited by strong
subsidence aloft. RH is likely to drop below 20 percent over
most of the Piedmont, with values less than 30 percent even in
mountain valleys where low afternoon RH is less common. There
could be a brief overlap of gusty winds with low RH such that
Red Flag conditions are not out of the question. SPC Day 5 fire
outlook issued Tue afternoon already highlights most of our area
in a 40% contour for low RH and wind. As the high centers north
of the area Saturday night, winds become very light and strong
radiational cooling is expected, and a light freeze is expected
in the mountains, NC foothills, and perhaps some spotty locations
in the I-40 corridor. This said, the first group of zones in the
spring frost-freeze program (GA/SC zones outside the mountains and
southern tier of NC Piedmont zones) do not activate until April 1.

The sfc high remains transient as the upper pattern progresses;
southerly sfc flow redevelops over the area Sunday afternoon, and
temps rebound a few degrees east of the mountains. By early Monday,
upper ridge axis extends from the Gulf to the northern Rockies, with
a broad warm sector taking shape in the Mississippi Valley ahead of
low pressure system passing south of Hudson Bay. Models/ensembles
vary in their placement of the associated frontal zone, but some
cloud cover and light precip are not out of the question near the TN
border as the front nears the mountains Monday or Tuesday. As the
ridge migrates eastward over that timeframe, thicknesses increase
and temps trend well above normal again.

&&

.AVIATION /13Z WEDNESDAY THROUGH SUNDAY/...
At KCLT and elsewhere: VFR continues for the 12z TAF cycle.
Scattered to broken cirrus visible on satellite, along with
a scattered mid-level altocu deck, mainly over the Upstate.
As anticipated winds have begun to trend ESE, and should turn more
decided SE in the next few hours.  They`ll turn S by afternoon,
and eventually to SSW by evening.

Outlook: VFR continues through at least Thursday night.  A cold
front may bring rain and associated flight restrictions on Friday
or Friday night.

&&

.CLIMATE...
RECORDS FOR 03-27

               MAX TEMPERATURE         MIN TEMPERATURE
  STATION      HIGH        LOW         HIGH        LOW
  -------  ----------  ----------  ----------  ----------
   KAVL      85 2020     32 1955     60 1921     11 1955
                                                    1894
   KCLT      85 1950     40 1894     62 1949     19 1955
                                        1944
   KGSP      86 2020     45 2011     60 1921     15 1894
                            1947

&&

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

&&

$$

JCW/MPR