Fort Mill, South Carolina 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

189
FXUS62 KGSP 262327
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
727 PM EDT Sat Jul 26 2025

.SYNOPSIS...
Oppressive heat and humidity build through the weekend, and
continue through the first half of next week. Dangerous heat indices
are possible, especially Sunday through Wednesday. Afternoon showers
and thunderstorms will be isolated except in the North Carolina
mountains. A cold front will finally arrive late in the week,
bringing an increase in showers and storms as well as much-needed
relief from the heat.

&&

.NEAR TERM /THROUGH SUNDAY/...
As of 725 PM Saturday: Isolated to low end scattered convection will
linger early this evening across the mountains with an isolated
shower possible elsewhere. Convection should dissipate by midnight.
After a record setting day for CLT/GSP, temps and heat indices are
slowly coming down. Will allow the Heat Advisory to expire on time.

Otherwise, the Southeast will remain under the influence of an upper
anticyclone that will continue to drift W/SW, with the center of the
high expected to move into the Deep South by the end of the period.
Conditions will therefore remain hot across our area through the
near term. Min temps will again by around 5 degrees above climo.
Morning fog/low stratus should again develop within the favored
mountain valleys by daybreak.

Short term guidance agrees that low level thermal trough will nudge
east of the CWA tonight, with a weak NW/downslope flow expected
to encompass the entire area for tomorrow. This should add another
degree or two to our heating potential, with high temps expected to
reach 100 in many locations southeast of I-85. Deep mixing is again
expected to result in surface dewpoints dipping into the mid/upper
60s in most areas, but coverage of 105+ heat indices should be more
widespread tomorrow...while the cumulative effect of a couple of
days of high heat along with very warm/muggy nighttime conditions
will make the heat more impactful, even if some areas don`t quite
meet the 105 criteria. The Heat Advisory has been expanded to
include all area except for the mountains and the northern NC
foothills. In terms of diurnal convective potential...forecast
soundings look, at most, marginally more favorable for updraft
development Sunday afternoon. 20-40 PoPs are carried across the
mountains and portions of the foothills.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
As of 100 PM EDT Saturday...

Key Messages:

1) Heat Wave Continues with Heat Advisory Criteria, and Possibly
Extreme Heat Warning Criteria, Each Afternoon East of the Mountains

2) Heat Index Values from 105 to 110+ Degrees F During Peak Heating
Each Day East of the Mountains

3) Diurnal Shower and Thunderstorm Chances will be Highest Across
the Mountains

The heat and humidity will be the main concern through the short
term as the heat wave lingers thanks to a large, hot upper
anticyclone continuing to building over the south-central CONUS
through Monday before stalling over the region on Tuesday.

Highs each afternoon east of the mountains will climb into the mid
90s to lower 100s. Dangerous indices are expected to develop east of
the mountains, ranging from 105-110+ degrees F each day during peak
heating. Thus, Heat Advisories are a good bet for early next week
for most locations east of the mountains. Extreme Heat Warning
criteria may be met for some locations east of the mountains (mainly
the Upper Savannah River Valley and areas along I-77) during peak
heating (mainly on Monday) so an Extreme Heat Watch may be needed if
confidence increases and if the trend of 110+ degrees F heat indices
holds. Highs across the mountain valleys will range from the upper
80s to lower 90s each day with higher elevations seeing highs range
from the mid 70s to mid 80s. Heat indices will reach into the upper
90s to lower 100s across the mountain valleys during peak heating
each day. There will not be much relief from the heat during the
overnight hours east of the mountains through the short term,
especially for those without access to air conditioning, thanks to
lows only falling into the mid to upper 70s. Limit strenuous outdoor
activities from 11 AM to 8 PM each day, stay hydrated, never leave
people or pets unattended in a locked car (look before you lock!),
and make sure to check on those more vulnerable to the heat
(elderly, sick, and those without access to AC). If you have to work
outside take frequent breaks in the shade, stay hydrated, and
monitor for signs of heat illness.

As for diurnal convective chances, the NBM continues to have the
highest potential for activity across the mountains through the
short term. The one glimmer of hope for locations east of the
mountains is a shortwave that will dive across the western Carolinas
and northeast Georgia on Monday. This could increase convective
chances area-wide but the ridge may suppress activity somewhat.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
As of 100 PM EDT Saturday...

Key Messages:

1) Heat Wave Lingers through Thursday with Heat Advisory Criteria
Possible Each Afternoon for Some Locations East of the Mountains

2) Much Cooler Temperatures Return Behind a Cold Front Friday into
Saturday, with Below Normal Highs Expected on Saturday

3) Shower and Thunderstorm Chances Increase Area-Wide Thursday into
Saturday with the Front

The hot upper anticyclone gradually breaks down through the long
term as a potent (for summer) upper trough digs across the
northeastern United States. So, although the heat wave will continue
through Thursday, the heat and humidity will start ticking down each
day through the long term, with much needed relief finally arriving
Friday into Saturday. So although it will be a hot (and arguably
miserable) end to July, it will be a nice and (arguably refreshing)
start to August!

A cooling trend is expected throughout the long term in regards to
both high and low temperatures. Highs will start out ranging from
the low to mid 90s east of the mountains each afternoon on Wednesday
and Thursday before dipping down into the lower 80s to lower 90s
Friday into Saturday behind a cold front. Heat index values may
climb near or even reach Heat Advisory criteria (mainly across the
Upper Savannah River Valley and along/near I-77) during peak heating
on Wednesday and Thursday (but especially on Wednesday). Lows east
of the mountains will be noticeably cooler as well, dipping into the
mid 60s to lower 70s starting Friday night. Highs each afternoon
across the mountains will range from the lower 70s to upper 80s on
Wednesday and Thursday before dipping down into the lower 60s to
lower 80s Friday and Saturday. Lows across the mountains will drop
into the mid 50s to mid 60s by Friday night.

As for convective chances, the NBM has the highest PoPs confined to
the mountains again on Wednesday but has PoPs increasing area-wide
starting Thursday ahead of the cold front. NBM then depicts PoPs
increasing further Friday ahead of and along the front, potentially
lingering into Saturday behind the front. Although shear increases
slightly with the front, cold air damming looks to develop towards
the end of the period. Thus, the severe weather threat should remain
low thanks to the wedge keeping us stable.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
At KCLT and elsewhere: Convection has limited mainly to the
mountains, but an isolated shower can`t be ruled out elsewhere early
this evening. Kept a VCSH at KAVL with no mentions elsewhere. VFR
cumulus and patchy convective debris should dissipate through the
evening. Mountain valley fog and low stratus is again anticipated,
but primarily in the valleys west of KAVL...so VFR is forecast to
prevail at all TAF sites through the period. Winds will vary from SW
to NW across the area this evening with light NW or light and
variable winds overnight. N to NW wind picks back up during the day
Sunday trending to more S to NW for the afternoon. Mountains have
the best chance for afternoon convection, so PROB30 limited to KAVL
for now. Scattered VFR cumulus expected for most locations again.

Outlook: Typical mid-summer weather is expected to continue thru at
least the middle of next week, with scattered to numerous diurnal
convection in the mountains, and isolated to scattered convection in
the Piedmont. Low stratus and/or fog will be possible each
morning...mainly in the mtn valleys.

&&

.CLIMATE...
RECORDS FOR 07-27

               MAX TEMPERATURE         MIN TEMPERATURE
  STATION      HIGH        LOW         HIGH        LOW
  -------  ----------  ----------  ----------  ----------
   KAVL      97 1952     70 1946     72 1936     48 1911
                                        1925
   KCLT     103 1940     74 1926     76 2022     57 1920
                                        2016
                                        1944
   KGSP     103 1940     70 1946     75 2012     54 1911
                                        1944



RECORDS FOR 07-28

               MAX TEMPERATURE         MIN TEMPERATURE
  STATION      HIGH        LOW         HIGH        LOW
  -------  ----------  ----------  ----------  ----------
   KAVL      98 1952     68 1890     70 2010     53 1895
                                        1878
                                        1877
   KCLT     102 1952     70 1890     78 2016     54 1962
   KGSP     103 1952     72 1926     76 2016     60 1911
                                        1936        1904



RECORDS FOR 07-29

               MAX TEMPERATURE         MIN TEMPERATURE
  STATION      HIGH        LOW         HIGH        LOW
  -------  ----------  ----------  ----------  ----------
   KAVL      98 1952     67 1984     74 1877     55 1911
                                                    1895
   KCLT     103 1952     72 1984     77 1993     59 1920
   KGSP     104 1952     70 1984     76 1949     59 1911
                                        1936



RECORDS FOR 07-30

               MAX TEMPERATURE         MIN TEMPERATURE
  STATION      HIGH        LOW         HIGH        LOW
  -------  ----------  ----------  ----------  ----------
   KAVL      93 1954     68 1936     72 2011     54 2014
                                        1878        1897
                                                    1895
   KCLT     101 2011     71 1981     77 1953     58 1914
                                        1941
   KGSP     101 1999     73 1981     77 2011     60 1914
                                                    1911
                                                    1884



RECORDS FOR 07-31

               MAX TEMPERATURE         MIN TEMPERATURE
  STATION      HIGH        LOW         HIGH        LOW
  -------  ----------  ----------  ----------  ----------
   KAVL      95 1999     65 1936     71 2011     53 1986
                                                    1914
   KCLT     100 1999     69 1936     77 1941     56 1914
                1931                    1931
                1915
   KGSP     104 1999     71 2014     78 1999     56 1936
                                        1931

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...Heat Advisory from noon Sunday to 2 AM EDT Monday for GAZ018-
     026-028-029.
     Heat Advisory until 8 PM EDT this evening for GAZ028-029.
NC...Heat Advisory from noon Sunday to 2 AM EDT Monday for NCZ036-
     037-056-057-068>072-082-508-510.
     Heat Advisory until 8 PM EDT this evening for NCZ036-037-056-
     057-069>072-082.
SC...Heat Advisory from noon Sunday to 2 AM EDT Monday for
     SCZ008>014-019-104>109.
     Heat Advisory until 8 PM EDT this evening for SCZ009>014-019-
     107-109.

&&

$$

SYNOPSIS...AR
NEAR TERM...JDL/RWH
SHORT TERM...AR
LONG TERM...AR
AVIATION...RWH
CLIMATE...