179
FXUS62 KGSP 232311
AFDGSP
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
711 PM EDT Mon Jun 23 2025
.SYNOPSIS...
The heat and humidity will remain elevated through mid-week as a hot
upper ridge dominates the eastern United States. Isolated showers
and thunderstorms will remain possible each afternoon and evening
through Tuesday, 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 for the latter
half of the week.
&&
.NEAR TERM /THROUGH TUESDAY/...
As of 530 pm Monday: Not much to add to the already stagnant
pattern. A few showers and thunderstorms are ongoing over the far
western mountains, but are already showing signs of dissipation.
Temps should start to cool through the overnight hours. However, not
by too much. Muggy and very warm conditions are expected
tonight...with min temps of 5-7 degrees above climo expected. Areas
of fog/low stratus will again develop...mainly in the lower mtn
valleys.
Progged thickness values support a continuation of the
heating trend on Tuesday, and max temps are expected to be
2-3 warmer then today...resulting in widespread upper 90s
east of the mountains...with at least isolated instances of
100 likely. Meanwhile, while forecast soundings depict deep
mixing during the afternoon...there is also an elevated moisture
source near the top of the mixed layer...lowering the potential
for decreasing dewpoints during the hottest part of the day. As
such...generally expect surface dewpoints to remain in the upper
60s in most locations, and this will result in widespread heat
index values of 105-110 across the Piedmont and foothills. A Heat
Advisory will therefore be issued for these areas. Otherwise,
another round of isolated diurnal convection is expected over
the mountains.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
As of 145 PM EDT Monday:
Upper anticylcone will be firmly in place as we start the short term
with hot and humid conditions across the area. Another day of
afternoon highs a good 10 or so degrees above seasonal normals and
dewpoints supportive of heat indices above 100 across all the
Piedmont, and above 105 in the Charlotte Metro and the Upper
Savannah Valley. For the NW Piedmont and GSP Metro, a little less
confident on dewpoints, given forecast soundings showing deep mixing
to 800mb, but current dewpoint trends are running fairly on track
with NBM and so less confident that there is need to undercut NBM as
much as in previous forecasts. Given the need to issue the near-term
heat advisory, likely need for advisory conditions for a chunk of
the area Wednesday, and collaboration with neighbors, felt it
prudent to go ahead and extend the advisory through Wednesday
afternoon even with the uncertainty that the entire Piedmont will
reach criteria.
All that said, upper weakness over the Western Atlantic shifts west
over the Southeast/FL Peninsula on Wednesday, working to begin
breaking down the upper ridge and bringing additional moisture into
the area. So even with the heat advisory, expect enhanced diurnal
pops, with likelies over the mountains. Surface thermodynamics
aligned with incoming vort max may allow for isolated strong to
severe, with wet microbursts the main threat. SPC Marginal for Day 3
seems reasonable. Enhanced diurnal coverage continues on Thursday as
waves of moisture rotate around the upper weakness and spread across
the southeast, and reduced insolation brings high temperatures down
to the mid 90s (hey, we celebrate the small victories here). Will
see the same trend in reduction of overnight lows but still >70
degrees so not much recovery to speak of, so the cumulative heat
effects will still compound.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 200 PM EDT Monday:
Upper weakness remains over the Southeast as we move into the
extended, drifting north and cutting into the ridge. General
thickness pattern still remains high however so even with some
reduction of temperatures, they still remain above normal...just
only a couple of degrees instead of 7-10 degrees. With increasing
deep-layer moisture associated with the disturbance, convective
chances increase through the extended, especially over the weekend.
With such warm temperatures, enough SBCAPE can be expected that
allow for isolated wet microbursts, as well as heavy rain leading to
isolated flash flooding.
&&
.AVIATION /23Z MONDAY THROUGH SATURDAY/...
At KCLT and elsewhere: VFR conditions prevail through the end of the
period as strong high pressure remains parked over the area. Winds
continue to be very light and VRB at all sites given the stagnant
pattern. KCLT could see more of a NE wind after daybreak, but again
remains very light. Cu is starting to dissipate quickly and should
leave SKC for the overnight hours. Given the lack of rainfall over
the past few nights, mountain terminals are seeing less vsby
restrictions from low stratus at daybreak. For this, will keep any
mention out. No vsby/cig restrictions are anticipated during this
TAF period. Expect the usual cu to re-develop over the area Tuesday
afternoon.
Outlook: Showers and thunderstorms return Wednesday and continue
through the end of the workweek. Fog and/or low stratus is possible
each morning in the usual mtn valleys and near lakes and rivers.
&&
.CLIMATE...
RECORDS FOR 06-23
MAX TEMPERATURE MIN TEMPERATURE
STATION HIGH LOW HIGH LOW
------- ---------- ---------- ---------- ----------
KAVL 93 2016 64 1936 70 2017 47 1947
1988
KCLT 100 2015 63 1936 77 2016 53 1947
KGSP 99 1988 70 1900 75 2016 54 1972
1944 1947
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 Tuesday to 8 PM EDT Wednesday for
GAZ018-026-028-029.
NC...Heat Advisory from noon Tuesday to 8 PM EDT Wednesday for
NCZ035>037-056-057-068>072-082-501>510.
SC...Heat Advisory from noon Tuesday to 8 PM EDT Wednesday for
SCZ008>014-019-101>109.
&&
$$
SYNOPSIS...AR/TDP
NEAR TERM...CP/JDL
SHORT TERM...TDP
LONG TERM...TDP
AVIATION...CP
CLIMATE...