935
FXUS62 KGSP 061917
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
317 PM EDT Fri Jun 6 2025

.SYNOPSIS...
Several storm systems moving across the area will allow for
scattered to numerous thunderstorms through the weekend with a few
possibly becoming strong to severe, mainly during the afternoon and
evening hours. Unsettled weather will stick around through the
middle of next week as a cold front stalls in/near the area.

&&

.NEAR TERM /THROUGH SATURDAY/...
As of 230 PM EDT Friday: Current surface analysis shows the low
pressure system that brought us some rain and clouds earlier this
week is moving off the southern Mid-Atlantic coast. Meanwhile,
a weak surface ridge is located over the southern and central
Appalachians. Strong daytime heating has led to the development of a
lee trough on the eastern side of the Blue Ridge Escarpment. Looking
aloft, the region is positioned in a belt of enhanced zonal flow
in between an upper ridge over northern Mexico and weak troughing
over the northern CONUS. This will provide a favorable pattern for
mesoscale convective systems (MCS) to develop over the Central
Plains, Midwest, and Ohio/Tennessee Valleys in the near term
and beyond.

The aforementioned lee trough will provide a focus for showers and
storms this afternoon. Convection along this boundary has struggled
to mature so far this afternoon, implying that convergence is
weak and shallow. ACARS soundings also show a weak subsidence
inversion around 14 kft AGL that these updrafts will have to
overcome. Steep low-level lapse rates, 1500 J/KG of MLCAPE, and
mid-level dry air will provide a relatively favorable environment
for wet microbursts. However, limited storm coverage and shear to
organize convection justify the marginal severe risk from SPC for
much of the area.

We are also monitoring upstream convection that are quickly
organizing into multiple MCSs over the Mid South and Mid Mississippi
Valley. This leading edge of this activity is expected to reach
the central and northern mountains of western NC around 7 or 8 PM
which is slightly earlier than previously expected. There should be
enough residual daytime instability to extend the severe weather
threat for our far western zones. The main convective threats
will be locally strong to damaging winds and cloud-to-ground
lightning. This activity should gradually weaken as it tracks
farther east into the Foothills this evening.

The next MCS tracking eastward across the lower Ohio and Tennessee
Valleys this evening is expected to move into western NC. CAMs
are in good agreement with the MCS weakening by the time it makes
it into the mountains which seems reasonable as it moves into an
increasingly stable boundary layer and becomes removed from the
better synoptic lift that remains upstream of the region.

Uncertainty regarding the severe weather potential during the day
tomorrow is high. The latest CAMs depict the region in a relative
lull in convection during the daytime in between tonight`s MCS
exiting the area in the morning and the next one remaining upstream
of us. This would greatly limit our storm coverage. Similar to
today, a favorable wet microburst environment will allow for
storms that do develop to be capable of producing locally strong
to severe winds.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
As of 100 PM EDT Friday...

Key Messages:

1) Unsettled Weather Continues into Sunday with a Brief Lull on
Monday

2) Strong to Severe Storms are Possible Sunday but Confidence is Low

3) Breezy Winds and Cooler Temps Return Sunday with Lighter Winds
and Warmer Temps for Monday

A cold front approaches out of the west Saturday night into early
Sunday before pushing across the forecast area late Sunday into
Sunday night. The front will wash out over the area on Monday before
another cold front approaches out of the west Monday into Monday
night. This will periodic shower and thunderstorm chances around
through the period, although a brief lull is expected on Monday. 12Z
CAMs are split on whether another MCS will push across the area
early Sunday as the most of the CAMS keep mostly dry conditions
around for most locations while the NAMNest depicts an MCS tracking
over the forecast area during the morning hours on Sunday. Thus,
confidence on PoPs is low for Sunday morning. The 12Z NAMNest shows
redevelopment of convection Sunday afternoon and evening ahead of
the front but with the rest of the CAMs not going out this far just
yet, and with global model guidance not being in agreement regarding
the coverage of convection, confidence on PoPs (and the severe
threat) remains low for Sunday. With 20-30 kts of deep layer shear
and up to 1,500 J/kg of SBCAPE developing during peak heating on
Sunday, a few strong to severe storms are possible. The main hazards
with any severe storms that develop are damaging wind gusts and
isolated large hail. The entire forecast area is highlighted in a
Marginal Risk for isolated severe storms on Sunday and this appears
warranted based on the expected parameters. We should get a better
idea of how convection will play out on Sunday as the 18Z and 00Z
CAMs come in, as they will go out past 12Z Sunday. Global guidance
is in fairly decent agreement that a lull in convection can be
expected on Monday so capped PoPs to chance for now. Global guidance
does show the potential for an uptick in PoPs Monday night but
confidence remains low as the latest ECMWF and Canadian have mostly
dry conditions while the latest GFS shows precip across the entire
forecast area. Thus, capped PoPs to chance through the end of the
short term. Slight cooler highs and breezy winds return Sunday
before lighter winds and warmer temps develop Monday. Highs on
Sunday will end up near to a few degrees below normal, becoming a
few degrees above normal on Monday. Lows each night will remain a
few to several degrees above normal.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 130 PM EDT Friday...

Key Messages:

1) Unsettled Weather Returns Tuesday and Lingers through the
Rest of the Workweek

2) Near to Just Below Normal Highs Return Tuesday and Wednesday

3) Slightly Above Normal Highs develop Thursday and Friday

The aforementioned cold front in the near term will push across the
forecast area late Tuesday into early Wednesday bringing better
shower and thunderstorm chances back to the forecast area. The front
looks to stall over the central/eastern Carolinas Thursday into
Friday keeping unsettled weather around. A few strong to severe
storms will be possible each day, mainly during the afternoon and
evening hours. Damaging wind gusts and large hail would be the main
hazards with any severe storms that manage to develop. Highs will
trend cooler and near to just below normal for Tuesday and Wednesday
before warming back up and trending slightly above normal Thursday
and Friday. Lows through the period will remain a few to several
degrees above normal through the long term.

&&

.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
At KCLT and elsewhere: Mainly VFR conditions expected through this
evening. However, there will is a possibility for localized/brief
restrictions in thunderstorms for the terminals in the mountains and
foothills. A 2-4 hr window for VCTS was included in the 18Z TAFs
for KAVL, KGSP, and KGMU where confidence in SCT pop up showers
and storms is highest in the vicinity of a surface trough that
will continue to sharpen near the Escarpment. Timing is greatest
between 21Z and sunset.

Multiple complexes of showers and storms that is developing in
the TN Valley this afternoon will approach the mountains this
evening and again overnight. There is uncertainty regarding how
far east this activity will make it after sunset, so opted to
keep any mention of TS or SHRA out of the TAFs for now. We will
be following radar trends closely and have a feeling we will have
to add them in to a few terminals through nowcasting. West winds
around 4-8 kt will veer out of the SW this afternoon except KAVL
will winds will generally remain out of the NW. The mid-level clouds
and showers tonight casts doubt on how extensive fog development
will be overnight. Backed off on restrictions at KAVL and KHKY.

West winds will increase to 10 kt Saturday morning. Gusts to 20
kt is expected to develop by mid to late morning (14Z-15Z). The
latest trend in convective-allowing models is to limit the storm
coverage on Saturday. Chances are too low to include in the 18Z
KCLT TAF at the moment.

Outlook: An active period is expected with scattered diurnal
showers and thunderstorms each day along with the potential for
late night/early morning fog/low stratus restrictions.

&&

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

&&

$$

SYNOPSIS...TW
NEAR TERM...JK
SHORT TERM...AR
LONG TERM...AR
AVIATION...JK