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642
FXUS62 KGSP 300723
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
323 AM EDT Mon Jun 30 2025

.SYNOPSIS...
A typical summer pattern continues with seasonable temperatures and
chances for afternoon and evening thunderstorms. A cold front
approaches the area Tuesday with a chance for stronger
thunderstorms. Behind the front, drier weather returns for the
holiday weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
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As of 210 AM EDT Monday: The region remains under broad flow and the
typical summertime pattern continues through the near term. Given
the higher dewpoints and weak to calm winds across most of the CWA,
there is the potential for patchy fog and low stratus to develop
through daybreak. Will continue to monitor. Meanwhile, the
persistent surface high off the eastern coastline remains parked as
is the norm for this time of year. Since the CWA is on the western
fringe of the high, southerly flow reinforces moisture advection.
Today, dewpoints are expected to be a tick higher as PWATs edge
upward towards 2.00". What this means is even more gross, humid air.
Not expecting much mixing out this afternoon given this moist air
mass, so unless a few pop-up showers can produce enough clashing
cold pools, the sweat remains in place. Speaking of afternoon
showers, rinse and repeat. A few diurnally driven thunderstorms are
likely to appear over the mountains near peak heating. Weak steering
flow aloft. Once again an inverted-V on modeled soundings show an
environment capable of rapid evaporative cooling. This is apparent
with dCAPE values nearing 1000 J/kg, increasing the chances for
strong winds out of developing downbursts. Cannot rule out a severe
storm, but it would mainly be for winds. Tonight could see a similar
setup with patchy fog occurring over areas that received rain.
Should there be a lack of spreading cold pools like on Sunday, this
would increase the chances. As for temperatures, low 90s east of the
mountains and overnight lows reaching to the lower 70s.
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&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
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As of 240 am Monday: Heights will fall across the East on Tuesday,
with a series of short waves traversing southeast Canada/the
northeast Conus carving out a trough east of the Appalachians by
Tue evening. Associated low level trough/convergence zone will
provide additional impetus for diurnal convection on Tuesday
as the atmosphere destabilizes to the tune of ~2000 J/kg and
precipitable water values remain AOA 1.75". PoPs are generally
advertised in the 70-90 range, with the highest chances forecast
across the mountains. Modest acceleration of the mid-level flow
will result in an increase in shear parameters...although they will
remain quite weak. Nevertheless, wind fields could be adequate to
allow for some small scale clustering along outflows. This along
with better overall coverage should result in an uptick in the
potential for isolated severe storms. Although cell movement is
forecast to increase to 10-15 kts, the increased coverage in a
very moist environment will maintain some potential for locally
excessive rainfall. Convection will steadily diminish, but likely
persist well into Tuesday night as the trough axis steadily shifts
east across the CWA.

Conditions will begin to dry out...especially in the mid/upper
levels on Wednesday in the wake of the trough axis, while
flow aloft will steadily become more anticyclonic. However,
sufficient low level moisture will linger to allow for moderate
destabilization during the afternoon, and isolated/widely
scattered convection should develop within this regime during
the afternoon/evening...with perhaps a pulse severe storm or two
possible. Temperatures are forecast to be right around normal
through the period.
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&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
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As of 310 am Monday: An upper ridge will gradually build to our
west and slowly shift east during the medium range...moving from
the Great Plains at the start of the period...to the vicinity of the
Appalachians by next weekend. This will result in steadily warming
mid-level temps, a tendency toward weak capping, and relatively dry
profiles across our area. This will result in limited potential for
diurnal convection...and PoPs are forecast at below-climo levels
(general 20-30% chances across the mountains and 10-20% elsewhere
through Saturday. Global models hint at some potential for a region
of lower heights to undercut the ridge across the Southeast by
the end of the period...and PoPs are allowed to return to near
climo for Sunday. Temperatures are forecast to creep to a couple
of degrees above normal for much of the period under rising heights.
-- End Changed Discussion --

&&

.AVIATION /08Z MONDAY THROUGH FRIDAY/...
At KCLT and elsewhere: VFR conditions prevail through the TAF period
at most sites. Similar to the last few days, winds remain calm/VRB
overnight. Higher moisture in the region is increasing the
development of patchy BR/FG across the area. Confidence is not high
enough at prevail at the typical mountain sites, but be aware that
passing BR could develop anywhere. Should start to slowly clear up
after daybreak. Will keep TEMPOs at KAVL/KHKY for BR. Monday looks
to be much of the same. Southerly winds pick up by mid morning and
into the afternoon timeframe, but still remains light. There could
be a few very low-end gusts over KCLT during the afternoon, but
would remain less than 15kts. The afternoon brings another chance
for scattered showers and TSRA, possible anywhere especially in the
mountains. Chances are higher for portions of the mountains so will
add a TEMPO at KAVL, with PROB30s elsewhere. Once showers and
thunderstorms clear up, another calm night ahead. Depending on
whether or not the mountain sites can receive any rain, will greatly
impact the BR/FG chances before the end of the TAF period.

Outlook: Daily chances for afternoon and evening showers and
thunderstorms into at least midweek. Fog and/or low stratus possible
each morning in the usual mountain valleys as well as near lakes and
rivers.

&&

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

&&

$$

SYNOPSIS...CP
NEAR TERM...CP
SHORT TERM...JDL
LONG TERM...JDL
AVIATION...CP