033
FXUS62 KGSP 301746
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
146 PM 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 TUESDAY/...
As of 140 PM EDT Monday: As in the past few days, convection already
ongoing across the mountains. In spite of guidance suggesting a
lower chance of convection outside of the mountains than the past
few days, coverage increasing across the NC Piedmont. Still expect
it to top out at low end scattered coverage. Isolated to low end
scattered coverage for the Upstate and NE GA. Mesoanalysis shows
similar conditions as well with a very unstable air mass, light bulk
shear, moderate DCAPE, and very high PW values. Any storm that can
get tall enough has the potential for a damaging downburst. Isolated
flooding is possible where storms train or are anchored to terrain.

Convection diminishes through the evening but an isolated shower or
storm may linger through midnight or so. There may be more in the
way of clouds overnight ahead of the approaching front but still
expect mountain valley fog with patchy fog elsewhere. Lows near
normal mountains and a few degrees above normal elsewhere.

The stagnant pattern finally begins breaking down Tuesday and a weak
upper trough and surface cold front move into the area from the
west. This will keep high PW values across the area and bring an
uptick in bulk shear. The increased clouds and lower thickness
values will help put highs a little below normal for the mountains
and near normal elsewhere. This will keep instability slightly
lower, but still reaching at least the moderate range. Deeper
moisture is expected as well limiting DCAPE and sfc delta theta-e
values. But given the increased forcing, overall severe thunderstorm
potential is higher as some weak organization may develop. Isolated
flood threat remains as well as storm coverage should be higher
despite faster cell movement.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
As of 100 PM Monday: An upper trough axis will cross the spine
of the Appalachians Tuesday night and set up roughly along the
East Coast Wednesday thru Thursday as the upper flow pattern
amplifies. This should push a cold front thru the forecast area on
Wednesday. Scattered diurnal convection is expected, with better
coverage to our southeast. Temps will be near climo. The front
pushes further southeast of the area Thursday, resulting in drier
conditions. Only very isolated showers or storms expected, mainly in
the mountains, as heights rise aloft and limit instability. Temps
Thursday will be a category or so warmer with less cloud cover
than Wednesday. Lows will be near climo.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 130 PM Monday: Relative dry weather is expected for the
Fourth of July holiday weekend (dry for early July). An upper
ridge will slowly build in from the Midwest to the Ohio Valley
and into the Mid-Atlantic. This will help suppress convection and
keep mid-level lapse rates weak. An axis of sfc high pressure will
extend from the Mid-Atlantic west to the Mid-MS valley, while a
front stalls out over FL and the Gulf. Below-climo PoPs is in the
forecast for Friday and Saturday. PoPs trend toward climo Sunday,
but the latest guidance has trended drier. This is due to the
uncertainty on a tropical low development along the stalled front
in the eastern Gulf. The 12z GFS has come in more in line with the
ECMWF on keeping any disturbance shunted south. Regardless of what
happens in the Gulf, PoPs should begin to ramp up to more typical
mid-summer levels, as a northern stream trough begins to dig into
the Upper Midwest and the upper ridge shifts east. Temps will be
close to or slightly above normal thru the period.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
At KCLT and elsewhere: Expectations this afternoon similar to the
past few days except an overall lower chance of convection outside
of the mountains. Therefore, have a TEMPO at KAVL and PROB30s
elsewhere. S to SW winds continue into the evening then diminish
overnight. Winds pick back up from the S to SW on Tuesday. Better
chances of convection across the board Tuesday with a weak frontal
boundary moving in from the west. However, due to TAF rules, the
only site that gets a mention this TAF set is KAVL. Mountain valley
fog expected once again, but remains unclear if restrictions develop
at KAVL or even second best locations of KHKY and KAND. Have left
them VFR for now.

Outlook: Chance of afternoon and evening showers and thunderstorms
continues Wednesday. Drier air moving in Thursday may help inhibit
convection into the weekend. 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...ARK/CP
NEAR TERM...RWH
SHORT TERM...ARK
LONG TERM...ARK
AVIATION...RWH