Eastanollee, Georgia Weather Forecast Discussion

346
FXUS62 KGSP 250016
AFDGSP
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
816 PM EDT Wed Sep 24 2025
.SYNOPSIS...
An unsettled pattern emerges ahead of a cold front and upper
trough with multiple rounds of showers and thunderstorms into the
weekend. Temperatures remain warm through Thursday before cooling
to near seasonable normal high temperatures into early next week.
&&
.NEAR TERM /THROUGH THURSDAY/...
As of 800 PM EDT Wednesday: Cloud cover continues to gradually
increase from the west and some scattered showers continue lifting
NE across the NC Piedmont. Seeing a line of showers and
thunderstorms approaching out of eastern TN and northern Georgia
this evening as well. Confidence is low on how well this line will
hold together as it pushes off the mountains later this evening into
tonight. A dearth of instability during the nocturnal minimum should
preclude any severe weather threat, but a strong storm with locally
gusty winds cannot be discounted should more organized structures
remain.
By Thursday, a positive tilt upper trough will gradually shift east
with a belt of enhanced flow and upper divergence translating across
the Appalachians. At the same time, the piece of energy in the base
of the trough is forecast to break off and begin evolving into a
closed upper low in the vicinity of the Lower Mississippi Valley. At
least some degree of shower activity will likely be ongoing across
the mountains with considerable cloudiness as well. CAM guidance
depicts redevelopment of convection during the afternoon across
portions of the area, but coverage and location remain somewhat
uncertain. Extent of cloud cover and lingering showers from
overnight activity will play a significant role in the evolution of
mesoscale details for the afternoon. One such scenario is that a
differential heating boundary materializes east of the morning cloud
cover and serves as the location for later convective initiation.
Guidance is also mixed on coverage with some CAM members depicting
mainly scattered storms. Depending on could cover, upwards of 2000
J/kg of surface-based instability will be present with 30-40kts of
deep-layer vertical wind shear. This will be sufficient for a couple
isolated severe storms with a threat for locally damaging winds.
Positive tilt of the trough and respective shear vector orientation
isn`t overly favorable for widespread organized convection and in
fact, should convective coverage become greater than expected there
would be a tendency for storms to become undercut by composite cold
pools.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
As of 1250 PM EDT Wednesday: The center of an upper low moves from
the Mid-South at the start of the period eastward into the Southern
Appalachians by the end of the period. At the surface, a cold front
moves into the area from the west Friday and stalls along the coast
by Saturday while a series of weak low pressure centers moves north
along the front. The deepest moisture and strongest forcing, along
with better instability, occurs on Friday as the front is moving
through. The precipitation will be more convective in nature, but the
severe chance will be lower than Thursday as the instability is
weak. Some mid level drying takes place on Saturday, but low level
moisture remains high with the low level flow turning more
northeasterly. Precip chances actually increase on Saturday with
better upper divergence ahead of the upper low, but thunder chances
are lower with weaker instability. Widespread heavy rainfall is
unlikely either day, but moderate QPF is expected. Isolated, brief
heavy rainfall will be possible in any storm, but the overall flood
threat is low. That said, any location where storms train over the
same area could lead to spots of nuisance flooding. Highs near
normal Friday drop below normal for Saturday. Lows above normal each
morning.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
As of 125 PM EDT Wednesday: The upper low remains in place on Sunday
before retrograding into Middle TN on Monday. It then opens up and
moves to the SC coast by way of GA Tuesday. The low moves east
Wednesday as a ridge builds into the OH Valley from the Desert SW.
At the surface, the front remains stalled over or near the Carolina
coast with waves of low pressure moving north along the front. High
pressure builds into the area from the north. These features keep a
moist E to NE low level flow across the area through the period,
although it does weaken on Wed as the front finally begins moving
east. The result is scattered showers for most of the area Sunday
and Monday with diminishing chances Tuesday and Wednesday. QPF is
generally light through the period which is good given the prolonged
nature of the precip chances. This keeps the flood threat very low
while helping the drought conditions across the area. Also, for now,
the 12Z GFS and its ensemble mean show one consolidated tropical
system but keep it well off shore. The Canadian and 00Z ECMWF show
two systems with one making a glancing blow to the Carolina coast.
As always, this could change so keep up to date with the latest
forecast. Highs remain near to slightly below normal until Wednesday
when they fall to around 5 degrees below normal. Lows will be
slightly above normal until Wednesday when they fall a few degrees
below normal.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
At KCLT and elsewhere: Active through the 00Z TAF period as a cold
front approaches out of the west. The front will remain west of the
terminals through the TAF period so winds will remain S/SW. Showers
and thunderstorms are steadily approaching out of the west ahead of
the front as of 00Z. How well this line holds together east of the
mountains will be the main forecast challenge through the TAF
period. Thus, went with PROB30s for SHRA east of the mountains this
evening into late tonight, with the exception of KCLT as this
terminal should remain dry. Confidence is higher that KAVL will see
SHRA so went with a combination of prevailing SHRA and
PROB30s/TEMPOs overnight into Wednesday morning. Confidence on
prevailing SHRA from 13Z-16Z is very low as guidance is not in
agreement on whether KAVL will see periodic rain or brief drying at
times during the morning hours. Confidence on the formation of
mountain valley fog remains low as increasing cloud cover and rain
should keep dense fog at bay. However, vsbys will lower in
association with rain overnight so have this account for in the
PROB30s/TEMPOs. Cigs will gradually lower late tonight into early
Thursday morning dropping mostly to MVFR levels, although IFR cannot
be entirely ruled out. There will be little improvement throughout
the day tomorrow regarding cigs but guidance shows KCLT having the
best chance to see VFR cigs return late tomorrow afternoon into
tomorrow evening. Models are in better agreement regarding TSRA
chances tomorrow afternoon/early evening so went with PROB30s across
the terminals. Winds will go light to calm and VRB this evening into
tonight, increasing again throughout the day tomorrow. Speeds will
range from 5-10 kts with low-end intermittent wind gusts expected to
develop again, mainly at KCLT, KGSP, and KGMU.
Outlook: Shower and thunderstorm chances, as well as associated
restrictions, continue for all terminals into the weekend thanks to
the cold front. Mountain valley fog and low stratus are possible
each morning but could be limited somewhat by both cloud cover and
rain.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.
&&
$$
SYNOPSIS...DEO
NEAR TERM...AR/TW
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...AR

NWS GSP Office Area Forecast Discussion