Fort Mill, South Carolina 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

777
FXUS62 KGSP 040600
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
200 AM EDT Mon May 4 2026

.WHAT HAS CHANGED...
Rainfall amounts are trending higher for the entire area for a
system crossing the region by midweek.

&&

.KEY MESSAGES...
1. Patchy frost will be possible early this morning in some
sheltered locations in mountain valleys. Sensitive plants in
those areas may need to be protected. Otherwise, generally dry
and trending warmer through Tuesday.
2. Another cold front brings rain to the area by midweek with a
low severe threat.

&&

.DISCUSSION...
Key message 1: Patchy frost will be possible early this morning in
some sheltered locations in mountain valleys. Sensitive plants
in those areas may need to be protected. Otherwise, generally dry
and trending warmer through Tuesday.

Skies will remain generally clear early this morning with offshore
high pressure dominating our weather. Although a few cirrus could be
seen owing to weak perturbations high aloft, they look too wispy on
satellite to expect much impact on temperatures this mornig. Good
radiational cooling conditions have already led to decoupling at
many locations outside urban heat islands. In some of the more
sheltered mountain valleys temperatures are on track to cool into
the mid 30s, with dewpoint depressions small enough for frost
formation. Patchy frost wording is included in the valleys this
morning where these conditions occur along with sufficiently light
winds. Coverage is too sparse however to justify a Frost Advisory.

Light southwest flow and continued mostly clear skies today will
lead to warmer temperatures compared to Sunday, close to daily
normals, except for some mountain valley and foothill locations
in the lee of NW-SE oriented ridges (such as the French Broad
Valley). Very weak instability may develop in the upper TN Valley
and in our northern mountains, and it is not entirely out of the
question a shower could develop there, though CAM consensus suggests
showers are more likely to develop just north of the CWA. Thus
we retain less than 10% PoP this afternoon. Temps will be warmer
tonight, near to slightly below normal, too warm for frost.

Low RH of 25-30% is expected across the area this afternoon,
but with winds too light to enhance fire danger. Frontal system
will enter the mid-MS Valley Tuesday, and winds will be stronger
as gradient builds between that system and the offshore sfc
high. Accounting for slightly deeper mixing than what the NBM
would suggest, RH should still mix out to near 30 percent, and a
few locations could briefly meet criteria for an Increased Fire
Danger Statement in NC, though fuel moisture may not be much of a
concern where greenup has occurred. A slight chance of showers also
will precede the front into the western slopes of the mountains
late Tue afternoon.


Key message 2: Another cold front brings rain to the area by midweek
with a low severe threat.

Next chance for rain is still on track for later in the week as a
developing trough ejects over the eastern CONUS Wednesday into
Thursday and brings a cold front through the area. Latest guidance
slows down the ejecting trough, but still allows for an increased
chance of showers and thunderstorms with a non-zero severe risk.
Moisture is slower to return than previous forecasts with light
southerly winds through Thursday. Current model guidance shows a
stout baroclinic zone on the western fringe of an area of high
pressure as early as Tuesday night, enhancing forcing and initiating
a QPF response. PoPs start to ramp up Tuesday night into Wednesday
ahead of the front in the mountains before becoming widespread
through Thursday. Model soundings show a bit of instability ahead of
the front later on Wednesday and overnight, which could help to fuel
the severe risk for locations east of the mountains. Somewhat strong
shear of 40-50kts  could provide moderate forcing. Additionally, QPF
response has trended higher, especially for locations in the
mountains that experience any training convection. At this time,
widespread rain totals have increased for the 24-hr period from
Wednesday to Thursday, now with a 60-70% chance to exceed 1.00". As
with any storm system this far out, a lot can change, including how
deep the trough digs, timing of the better forcing with instability,
and how much moisture actually returns. Given all this, confidence
is increasing that a system should cross the area and bring rain
with the potential for thunderstorms, with an isolated severe risk.

After Thursday, high pressure returns into the weekend and keeps the
weather relatively quiet and warm.

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
At KCLT and elsewhere: VFR, and mostly SKC aside from FEW cirrus
today. Light SW winds this morning, except NW at KAVL, with
periods of calm possible at all sites. Winds pick up from the SW
after daybreak; KAVL probably will see some variability but should
settle to SW by around 16z. A few low-end gusts will be possible
this afternoon at all sites. Continuing light SW winds tonight.

Outlook: Expect dry/VFR conditions to linger through
Tuesday. Periodic restrictions are likely with next frontal system
Wednesday and Thursday. Low confidence for forecast Friday into
next weekend but restrictions cannot be ruled out at that time.

&&

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

&&

$$

CP/JCW