631
FXUS62 KGSP 240710 CCA
AFDGSP

Area Forecast Discussion...CORRECTED
National Weather Service Greenville-Spartanburg SC
310 AM EDT Tue Jun 24 2025

.SYNOPSIS...
The heat and humidity will remain elevated through Wednesday as
a hot upper ridge dominates the eastern United States. Isolated
showers and thunderstorms are expected this afternoon and evening,
mainly across the mountains. The upper ridge will begin to break
down after Wednesday as an upper disturbance brings increased
shower and thunderstorm chances to the area each day from Wednesday
through the weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 220 AM EDT Tuesday...

Key Messages:

1) Oppressive Heat Today with Heat Indices from 100 to 108 Degrees F
Mainly East of the North Carolina Mountains

2) Heat Advisory Remains in Effect

3) Isolated Diurnal Convection Expected Across the Mountains Again

Clear skies and dry conditions remain in place across most of the
forecast area this morning outside of some patchy to locally dense
fog and low stratus in the Little TN Valley. Any Fog and stratus
that develops across the mountain valleys should lift within an hour
or two after sunrise. Muggy and warm conditions will continue
through daybreak with temps only falling into the low to mid 70s
east of the mountains. Lows will end up around 8-10 degrees above
normal.

A large and hot upper anticyclone remain parked over the eastern
United States through the near term with the ridge expected to start
weakening tonight. Heat and humidity will peak today, with highs
climbing into the upper 80s to lower 90s in the mountain valleys and
the upper 90s east of the mountains. A few areas east of the
mountains may even reach 100 degrees F this afternoon. This will
lead to highs around 10-13 degrees above normal. We will get within
a few degrees of the record high max temps at the climate sites
today but confidence on whether we will actually break any records
this afternoon remains low. With dewpoints only expected to mix down
into the upper 60s to lower 70s, heat indices will climb into the
lower 100s for most locations east of the North Carolina mountains.
However, the Caldwell, Burke, McDowell, Rutherford, and Polk
mountain zones are likely to see heat indices in the triple digits
as well. Heat indices will range from 105 to 108 degrees F this
afternoon and early evening across the North Carolina Foothills and
Piedmont, the South Carolina Upstate, portions of northeast Georgia,
and the Caldwell, Burke, McDowell, Rutherford, and Polk mountain
zones. Thus, a Heat Advisory Remains in effect starting at noon.
Another round of isolated showers and thunderstorms is possible
this afternoon and evening, mainly across the mountains. Drier
conditions return tonight and some stratus and patchy fog may
develop again in the mountain valleys.

With temps tonight expected to remain warm and muggy, and a few
degrees warmer compared to this morning, we will maintain the Heat
Advisory through the overnight hours. Lows tonight will end up
around 8-12 degrees above normal. We may be able to tie or break the
record high min temps at the climate sites tonight based on the
latest forecast for tonight`s lows.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
As of 230 AM EDT Tuesday: Upper anticyclone begins to weaken and
retrograde slightly into the Ohio Valley Wednesday, allowing a
weak low pressure wave to drift NW into/near FL. This weakening,
combined with strong sfc heating from this ongoing heatwave will
likely be enough to support strong instability and weak to no CIN
by mid to late aftn. Pretty much all the guidance, including the
CAMs agree on scattered to numerous showers and storms forming
across the area, focusing in the high terrain and along a thermal
sfc trough over the Midlands. Then outflow boundaries will likely
trigger new storms and work over most of the forecast area by mid
to late evening. Given sbCAPE values possibly 3000-4000 J/kg and
high DCAPE, several severe wet microbursts are possible across the
area. The new Day 2 convective outlook from SPC has upgraded to a
slight risk, which makes sense given the environment and convective
response in the models. Assuming convection doesn`t get going until
mid to late aftn, max temps will likely get into the upper 90s with
dewpts hovering in the upper 60s to lower 70s. So, Wednesday`s heat
index values look to be similar to Tuesday`s expected values. No
changes needed to the Heat Advisory for Wednesday.

The upper high will continue to weaken Thursday, and the heat
should abate slightly thanks in part to convective overturning on
Wednesday. It will still be a hot day, with highs only in the lower
to mid 90s east of the mountains. Heat index values will top out in
the upper 90s to around 104. So a heat advisory isn`t likely to be
needed. Still expect decent coverage of convection during the aftn
and early evening, but the environment should not be as conducive
to severe microbursts. A handful of marginally severe pulse storms
will be possible. Muggy conditions expected both Wed and Thu nights,
with lows in the 60s mountains and lower to mid 70s in the Piedmont.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
As of 230 AM EDT Tuesday: A weakness in the upper ridge will settle
over the Southeast and linger thru the weekend. This feature will
keep the region unsettled, with above-climo diurnal PoPs expected
each day thru Monday. Temps will remain a few degrees above normal,
as well. The convective mode will mostly be pulse storms with a few
isolated microbursts and an isolated/localized flash flood threat.

&&

.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
At KCLT and elsewhere: VFR through the 06Z TAF period. Most
terminals will remain dry although KAVL could see some SHRA/TSRA
develop in the vicinity this afternoon and evening. However,
confidence is too low to mention in TAF at this time. Winds will
gradually turn NE through late this morning but could go light and
vrb to calm at times through daybreak. Winds will generally remain
ENE to NE through early this evening before going light and VRB to
calm again tonight into daybreak Wednesday. Clear skies are in place
across the terminals but cloud cover will gradually increase through
the period, becoming SCT to BKN. Mostly upper cirrus are expected
but FEW to SCT cumulus will develop again during peak heating today
before dissipating around sunset this evening. Patchy fog and MVFR
cigs may develop tonight into daybreak Wednesday at KAVL but
confidence remains low at this time.

Outlook: Showers and thunderstorm chances return Wednesday and
linger into the weekend. Fog and/or low stratus is possible each
morning in the usual mountain valleys as well as near lakes and
rivers.

&&

.CLIMATE...
RECORDS FOR 06-24

               MAX TEMPERATURE         MIN TEMPERATURE
  STATION      HIGH        LOW         HIGH        LOW
  -------  ----------  ----------  ----------  ----------
   KAVL      94 1952     66 1991     70 2015     48 1947
                            1919                    1918
   KCLT     102 1930     68 1936     76 1998     55 1972
                                        1914        1936
   KGSP     100 1952     64 1936     76 2016     51 1915



RECORDS FOR 06-25

               MAX TEMPERATURE         MIN TEMPERATURE
  STATION      HIGH        LOW         HIGH        LOW
  -------  ----------  ----------  ----------  ----------
   KAVL      96 1952     63 1889     69 1949     45 1972
                                        1943
                                        1891
   KCLT     102 1914     70 1980     75 1952     53 1889
                            1915        1914
                            1889
   KGSP     101 1952     69 1980     75 1931     52 1972
                                        1925



RECORDS FOR 06-26

               MAX TEMPERATURE         MIN TEMPERATURE
  STATION      HIGH        LOW         HIGH        LOW
  -------  ----------  ----------  ----------  ----------
   KAVL      96 1948     65 1961     69 1952     49 1984
                                                    1974
   KCLT     102 1952     68 1965     78 1948     55 1979
   KGSP     100 1952     71 1991     77 1952     55 1979
                1934                                1974
                1914

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...Heat Advisory from noon today to 8 PM EDT Wednesday for GAZ018-
     026-028-029.
NC...Heat Advisory from noon today to 8 PM EDT Wednesday for
     NCZ035>037-056-057-068>072-082-501>510.
SC...Heat Advisory from noon today to 8 PM EDT Wednesday for
     SCZ008>014-019-101>109.

&&

$$

SYNOPSIS...ARK
NEAR TERM...AR
SHORT TERM...ARK
LONG TERM...ARK
AVIATION...AR/ARK
CLIMATE...GSP