814
FXUS62 KGSP 061340
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
940 AM EDT Sun Apr 6 2025

.SYNOPSIS...
A strong cold front brings showers and thunderstorms Sunday into
Monday, before dry and cooler conditions return midweek. Scattered
showers may return to the area by next weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
Key Messages

1) Multiple rounds of showers and thunderstorms for the area through
tonight ahead of a cold front.

2) Nuisance flooding possible with training showers and
thunderstorms producing locally heavy rainfall.

As of 932 AM Sunday: A lead line of showers and thunderstorms that
pushed into the mountains early this morning has weakened with a
broad band of light to moderate showers currently extending across
the mountains. Upstream convection continues to slowly march towards
the area with regional radars depicting the northern reaches of a
QLCS in northern Georgia with the line extending southeast into
central Alabama. This activity will begin to push into the area late
this morning and into the afternoon. Considerable cloud cover along
with very dry profiles sampled in ACARS soundings will generally
preclude a greater severe weather threat with limited instability
and poor thermodynamic profiles. Nonetheless, an isolated strong to
marginally severe storm or two cannot be completely ruled out with
locally damaging winds and an isolated tornado.

Otherwise, a trough out west deepens as the ridge over the southeast
breaks down, allowing for a frontal boundary to push into the area
through Monday. Ahead of the front, southerly surface winds maintain
moisture advection and ripen the region for showers and
thunderstorms. Given the NE/SW orientation of the approaching line
of showers and storms, many areas will see multiple rounds of
rainfall, especially in the far western zones. QPF response at this
time is anywhere from 1.75 to 2 inches through the end of this
period, with locally higher amounts in the upslope zones. This
includes where ongoing wildfires are still burning. Nuisance
flooding is the main concern at this time, but should heavier rain
train over poor drainage areas or smaller streams, there could be
enough to warrant flood advisories. At this time, given the drier
antecedent conditions of the area, no flood watch will be issued.
Breezy and low end gusty winds with these squally storms is
expected, with higher gusts where there are stronger thunderstorms.
Temperatures remain warmer than normal Sunday as the arrival of the
actual cold front is into the next forecast period.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
As of 250 AM EDT Sunday: All indications are that our conveyor belt
of moisture/precip should linger over the fcst area through the
better part of the day on Monday, even as the sfc front could move
east of the fcst area early in the day. The position of the boundary
favors keeping the better QPF/rates to our east on Monday, so we
should only have to deal with lingering lighter rainfall amounts
with less of a chance of deeper convection and thunderstorms, if all
goes according to plan. Note the Day2 Excessive Rainfall Outlook
has the Marginal to our east and that looks reasonable. Temps
will probably be a few degrees on the cool side of normal owing
to the cloud cover and precip. It will take until overnight for
the cooler air to spill in after the main short wave axis sweeps
the remaining precip off to the east. Tuesday will be a typical
breezy and cool post-frontal day, with temps topping out about
ten degrees below normal with full sun as high pressure builds in
from the northwest. The pattern is progressive enough to allow
this high to settle over the mtns by early Wednesday morning,
setting up good radiational cooling conditions. The trend on the
morning low temps Wednesday has been creeping down and down to the
point where it looks more and more likely that we will get near or
below freezing in the I-40 corridor east of the mtns, with more
widespread frost potential elsewhere outside the mtns. Still too
early to issue a Freeze Watch, but that is where we are going. So,
you might want to hold off with planting stuff outdoors until
after this air mass moves through.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 159 AM EDT Sunday: One more seasonally cool, but otherwise
nice day on Wednesday with high pressure over the Mid-Atlantic
region, but the sfc high steadily moves off the coast by the end of
the day and off to the northeast Wednesday night. Meanwhile, model
guidance remains in good agreement overall, with a strong short
wave dropping down across the nrn Plains and digging a mid/upper
trof over the Upper Great Lakes/Midwest through Wednesday night. The
main differences are with regard to how quickly the wave can close
off an upper low and where that low will be located as we go into
Saturday. Either way, it would appear that precip won`t reach
the mtns until after daybreak Thursday, but more likely in the
afternoon. The arrival should be late enough to allow for temps
to rebound back toward normal for afternoon highs Thursday. The
better forcing is expected to rotate through the trof to our west
and overhead later in the day and into Thursday night/Friday
morning. Not taking any bets from Friday onward, because model
solutions get more divergent with how long the upper low lingers
and if any sfc cyclogenesis will take place close enough to impact
our weather, in particular the potential for some wrap-around
moisture/precip that affects the TN border zones Friday night into
Saturday morning. Assuming this system remains progressive enough,
precip should end by Saturday daybreak as high pressure builds
back in. At any rate, this should serve to keep our temps on the
cool side of normal through the rest of the period.

&&

.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
At KCLT and elsewhere: Conditions are starting to deteriorate
this morning as a line of storms moves into the area from the west
and restrictions set in. Patchy low level stratus continues to form
over some of the mountain areas west of KAVL, but anticipate this to
not affect the airport. After 13z, a line of showers and
thunderstorms approach KAVL and may reach the airport. There is
higher confidence for SHRA and will keep a PROB30 for TSRA. For this
afternoon, all terminals will have a PROB30 for TSRA as confidence
is not high enough, but this could change. Either way, expect SHRA
at KAVL this morning and at all sites this afternoon through the
rest of the TAF period, with TSRA possible. With the SHRA, vsby
restrictions are anticipated at all terminals through the end of the
period as well, with MVFR/IFR expected. Winds will be gusty at times
15-25kts and sporadic where there are showers, but should prevail
S/SW through the forecast.

Outlook: Showers and thunderstorms with associated restrictions
linger over the area into Monday afternoon. Dry conditions
return and should persist through mid-week.

&&

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

&&

$$

SYNOPSIS...CP
NEAR TERM...CP/TW
SHORT TERM...PM
LONG TERM...PM
AVIATION...CP