546
FXUS62 KGSP 021112
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
712 AM EDT Sat May 2 2026

.WHAT HAS CHANGED...
Updated discussion for 12z TAFs.

Rainfall amounts have trended still lower for today. No issuance
of Frost Advisory being made at this time for tonight, due to
low confidence.

&&

.KEY MESSAGES...
1. Light rain near and south of I-85 this morning, tapering off
in the afternoon. Temperatures will remain well below normal.
2. Cool temperatures across the mountains Saturday night could
result in frost early Sunday morning. Precautions may need to be
taken to protect sensitive plants.
3. Another cold front may bring rain to the area during the middle
part of the week, but the chances for significant rain or severe
storms remain low.

&&

.DISCUSSION...
Key message 1: Light rain near and south of I-85 this morning,
tapering off in the afternoon. Temperatures will remain
well below normal.

A broad area of high pressure gradually expands into the lower
MS Valley and across the Appalachians this morning; this looks
to result in dry/cold advection into our CWA from the northwest
today. Aloft, preceding the high, a well defined shortwave is set
to swing across the Southeast CONUS. A weak sfc wave develops as
the shortwave activates a quasi-stationary surface front along
the Gulf Coast, and some warm upglide will occur across GA/SC/NC
in the sloped baroclinic zone, with the upglide really only seen
at 800-700 mb over our southeastern zones (roughly along/SE
of I-85). The better low-level moisture and forcing looks to
remain to our southeast. As seen on earlier model progs, a sharp
gradient of precip appears likely to result. North of I-85, it
appears questionable much if any precip will occur due to the warm
front. The warm frontal precip peaks in coverage/rates this morning
and diminishes through early afternoon. The push of the cold front
east of the mountains later this afternoon, however, could result
in a few showers or even a brief thunderstorm as a shallow layer of
instability develops. Such activity looks most likely in the upper
Savannah Valley and vicinity, per REFS members and consistent signal
from multiple HRRR runs, though the HRW-FV3 and 3km NAM hint at
a little development in the NC Piedmont by early evening. QPF has
trended down on most guidance, with an even sharper gradient seen
in the NBM than on earlier runs. Most areas between I-85 and I-40
look to get only a few hundredths at most out of the warm front,
with amounts along our southeast border generally 0.10"-0.30". The
development of showers along the cold front could result in another
few hundredths to a tenth of an inch per the REFS PMM.

Temps remain a bit tricky with the competing influences of the cold
front, downsloping, and also the potential for diabatic cooling as
the warm frontal precip falls into the dry airmass. Regarding max
temps, most guidance has trended warmer on account of the lower
QPF, though e.g. the NAM still shows some sudden 5-10 degree drops
after the onset of its precip. Afternoon maxes look to be mainly
in the mid-upper 60s across the upper Piedmont and Foothills due
to downsloping, and lower 60s in the mtn valleys and far SE zones
where the warm frontal rain lasts the longest.


Key message 2: Cool temperatures across the mountains Saturday night
could result in frost early Sunday morning. Precautions may need
to be taken to protect sensitive plants.

Northwest winds will continue in cold advection tonight into Sunday
morning, as sfc high shifts east and centers over TN/KY. Mixing
of some modest gusts of 20-25 kt likely will occur in the late
afternoon and evening along the Blue Ridge Escarpment and in higher
elevations along the TN border. Some upslope cloud cover appears
possible, particularly as shallow instability over East TN may
lead to cumulus or stratocu along the crest of the Appalachians
which could spill into western NC through late evening, and/or
a slight amount of moisture may be present in the upslope layer
to produce stratus later in the night. The clouds would appear to
be more of a factor in the evening, however. The CAA alone appears
capable of bringing temps into the mid 30s in higher elevations near
the TN border, and as winds subside and cloud potential decreases
later, further radiational cooling still could result in very high
elevations above 5000 ft dipping below freezing, and could allow
frost to form in those areas in the mid 30s. Temps likely will
bottom out in the lower 40s for the Piedmont. Altogether these
temps are about 10-15 below normal.

A Freeze Warning would not be issued in this situation because of
the lack of agriculture and people living above 5k feet, with the
possible exception of Avery County. Confidence remains too low to
justify issuing a Frost Advisory based on the findings above; will
let day shift evaluate the trends for one more cycle. By Saturday
afternoon, check back to see if any preparations need to be made
to protect your plants if you live in the mountains.


Key message 3: Another cold front may bring rain to the area during
the middle part of the week, but the chances for significant rain
or severe storms remain low.

High pressure keeps the weather quiet through most of the week.
Model guidance hints at another possibility for a frontal boundary
to cross the area towards midweek, but confidence is very low at
this point. The overall synoptic trend evolves a trough that swings
southward and supports the potential for rain chances. Depending on
how the ridge out west progresses throughout the week will either
enhance or weaken the chances for a FROPA. If things were to remain
on track, there could be a potential for convective activity. How
much of the possible showers and thunderstorms become problematic is
yet to be determined. Guidance does hint at ample moisture return
ahead of the frontal passage, so thunderstorms are possible,
especially with the upper support. Still too early to pinpoint
details, but it`s something to continue to watch. Temperatures warm
back up through the week as well.

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
At KCLT and elsewhere: Bands of -RA expected along a SW-NE axis
across the Southeast this morning, oriented such that the SC sites
and KCLT are likely to see periods of -DZ and/or very light RA but
with restrictions generally unlikely. KCLT will arguably have the
best availability of moisture aloft and some MVFR cigs/vsby have
already been reported nearby, so did feel a TEMPO was warranted
for such early on. A few sprinkles are possible at KAVL and KHKY
but with minimal impact and confidence that the precip bands will
remain south of those sites. A period of low VFR or locally MVFR
cigs may continue through midday following showers, with VFR
the rest of the TAF. Winds will be very light NE this morning,
briefly turning SW for a time again during mixing ahead of a cold
front this afternoon. The front also could kick off a few showers,
and given consistency in guidance signals for such development
near KAND, added a PROB30 there. VCSH at KGSP/KGMU is also a nod
to that possibility. Behind the front, winds go NW again tonight
and possibly gust at 15-20 KT.

Outlook: Dry/VFR conditions return by Sunday and linger through
the first half of the workweek. Restrictions possible with next
frontal system Wednesday night or Thursday.

&&

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

&&

$$

CP/JCW