519
FXUS62 KGSP 092107
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
507 PM EDT Sun Mar 9 2025

.SYNOPSIS...
A low pressure system crosses the Southeast and brings increasing
rain chances and cooler temperatures through Monday before dry high
pressure returns Tuesday into Wednesday. Well above normal
temperatures return on Tuesday and will linger through the weekend.
Rain chances may return for some locations on Thursday but better
chances are expected this weekend as a strong cold front tracks
across the region.

&&

.NEAR TERM /THROUGH MONDAY/...
As of 504 PM Sunday: No major changes to the forecast this
afternoon.  Upper low now analyzed over southern Arkansas, and
digging ever farther east...with associated surface low churning
over the central Gulf Coast.

That sfc low will steadily deepen as it moves slightly inland
across the Deep South states tonight, before "transferring" off the
Southeast Coast in "Miller-A" fashion tomorrow. Frontogenetical
forcing and deformation zone north of the cyclone will become
increasingly organized with time, with increasing precip chances
across our forecast area, especially late tonight into Monday. Based
upon a consensus of model guidance, likely-to-categorical PoPs
are warranted across ~the SW quarter of the CWA by 12Z Monday,
with those PoPs advancing as far north as the southern tier of
NC forecast zones by late Mon morning. Precip chances taper off
toward the north such that they are slight chance at-most across
the northern tier. Rainfall amounts are forecast to range from
0.25-0.5 inch across much of northeast GA and upstate SC...with
possibly higher amounts across the Lakelands, while lesser
amounts are expected across western NC. Lowering/thickening cloud
cover is expected to limit the diurnal temp range, with mins
expected to average a few degrees above normal (despite the cool
start). Meanwhile, max temps Monday are expected to be at least 5
degrees cooler than today in areas where precip is most likely...
while northern areas should see highs similar to today.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As of 100 PM EDT Sunday...

Key Messages:

1) Drier and Warmer conditions Return

2) Fire Danger Concerns May Also Return Each Afternoon/Early Evening

Rain chances will linger mainly south of I-85 through early Monday
evening before gradually tapering off as the sfc low pushes into the
western Atlantic. The northern periphery of a dry sfc high centered
over the Gulf will build into the Southeast Monday evening into
Tuesday night. The center of the sfc high will track east across
Florida early Wednesday before pushing into the western Atlantic
late Wednesday. This will allow the western periphery of the sfc
high to remain over the Carolinas through the end of the short term,
allowing dry conditions to continue. Although wind gusts will
generally be 15 mph or less each day, minimum relative humidity will
drop to 30% or less during peak heating for most locations. This may
allow fire weather concerns to return on Tuesday and/or Wednesday
but any increased fire danger will be heavily dependent on how much
rain we receive on Monday. Well above normal temperatures can be
expected each afternoon with highs climbing into the low to mid 70s
across the mountain valleys and east of the mountains. Lows will
depict a gradual warming trend through the period, trending well
above normal by Wednesday night.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 130 PM EDT Sunday...

Key Messages:

1) Warm and Well Above Normal Temperatures Continue

2) Rain Chances May Return for Some Locations Thursday with Drier
Conditions Possible on Friday

3) A Strong Cold Front Brings Gusty Winds and a Better Chance for
Rain this Weekend

A weak cold front will approach the forecast area on Thursday and
may increase rain chances Thursday afternoon/early evening, mainly
across the western zones. However, confidence on this remains low as
the latest global model guidance show most of the moisture
associated with the front gradually falling apart as it approaches
the western Carolinas and northeast Georgia. Thus, capped PoPs to
chances across the western half of the forecast area for now. Drier
conditions may return Thursday night into Friday but global guidance
shows rain lingering across portions of the forecast area in
association with the weak frontal boundary. However, opted to go
with the NBM  for now in collaboration with neighboring WFOs (and to
keep the forecast consistent) which led to no mentionable PoPs
during this timeframe.

A stronger cold front will approach out of the west on Saturday
before pushing across the forecast area on Sunday. This will bring
better rain chances than we have seen in a while as well as gusty
winds. Have PoPs gradually ramping up overnight Friday into early
Sunday morning to account for the front. Models are in fairly good
agreement (despite this being days 6-7) and depict the bulk of rain
occurring overnight Saturday into late Sunday morning. However,
exact timing details remain murky as some slight timing differences
are noted regarding both the onset and offset of rain. Thus,
confidence on PoPs is moderate at best. This system has the
potential to bring heavy rainfall but any hydro issues look to be
low for now. This is due to the the LREF only showing a 15% to 30%
chance of seeing 3" of rainfall or greater across the favored SW
upslope zones this weekend. Elsewhere, the LREF generally shows less
than a 30% chance for 2" of rainfall this weekend. Thus, this looks
to be mainly a beneficial rainfall event for now. Nonetheless, we
will continue to monitor rainfall/hydro trends with this system in
the coming days. Additionally, there is also the potential for
severe weather with the front. However, confidence on this remains
low at this time with this being towards the end of the forecast
period. Models show anywhere from 50-70 kts of shear on Saturday and
70-90 kts of shear Saturday evening into Sunday afternoon ahead of
the front. The LREF mean shows the potential for 100-200 hundred
J/kg of MUCAPE Saturday into Sunday afternoon. However, if the
timing of the front holds (overnight Saturday into Sunday morning)
this may limit destabilization somewhat. Stay tuned to the latest
forecast information regarding possible impacts with this front as
details will become clearer the closer we get to the weekend.

&&

.AVIATION /21Z SUNDAY THROUGH FRIDAY/...
At KCLT and elsewhere: Mid and high level cloud cover will continue
streaming over the Terminal Forecast Area through this evening. An
area of -SHRA/perhaps sprinkles will pass near the upstate SC
terminals this afternoon...but is unlikely to impact the TAF sites,
while the potential for restrictions through this evening is very
low. Moisture and lift will steadily increase after midnight, and
chances for -SHRA will increase as a result, w/ Prob30s for such
introduced at most sites. Chances for cig restrictions (mainly MVFR)
will increase toward sunrise at the SC terminals, with MVFR cigs
expected to expand to KAVL and KCLT after sunrise. Categorical -SHRA
are also introduced during this time frame, with some potential for
visby restrictions during periods of higher precip rates.
Restrictions and precip potential will continue through the end of
the period. Winds will be light through this evening...possibly
favoring a SE direction. Winds will then become NE between 09-12Z
and steadily increase through the morning...becoming around 10 kts
by the end of the period.

Outlook: Steadily improving conditions and diminishing precip
chances are expected Mon afternoon into Mon evening. Dry high
pressure builds in Mon night into Tuesday and generally continues
through the week, although a front may bring brief showers and
restrictions Thursday.

&&

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

&&

$$

SYNOPSIS...AR
NEAR TERM...JDL/MPR
SHORT TERM...AR
LONG TERM...AR
AVIATION...JDL