Simpsonville, South Carolina 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

325
FXUS62 KGSP 040545
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1245 AM EST Wed Dec 4 2024

.SYNOPSIS...
Unseasonably cold air remains in place through tonight before a
brief warm-up mid-week.  The next cold front crosses our region
Thursday dropping temperatures again to well below normal to start
the weekend. A wetter weather pattern is possible by the middle of
next week.

&&

.NEAR TERM /THROUGH TODAY/...
As of 1230 am Wednesday: The center of surface high pressure will
settle over the southern Appalachians this morning, with resultant
light winds, clear skies, and low dewpoints combining to yield min
temps 15 to 20 degrees below normal across much of the area.

Otherwise, broad upper troffing will move off the Atlantic Coast
later today, allowing heights to modestly rebound over the
Southeast. By the end of the near-term period early Thurs, the upper
trof will amplify again over the Great Lakes with the trof axis
remaining to our north. At the sfc, high pressure will steadily
slide eastward today, and will be moving offshore as the period ends
early Thurs. Meanwhile, a relatively dry cold front will approach
the fcst area from the NW and will be moving over the NC mtns as the
period ends. We should remain dry except for some slight-to-low
chance PoPs over the NC mtns during the last few hrs of the period
early Thu morning. Any QPF that does fall should be minimal, however
profiles will likely be cold enough to produce a light wintry mix
with minor accums above roughly 3500 ft. In addition, gradient winds
from the SW will strengthen over the area this aftn/evening with
gusts continuing to intensify thru the end of the period. This
could result in Wind Advisory criteria gusts over portions of the NC
mtn zones...with solid Advisory/possibly High Wind Warning criteria
over parts of the northern NC mtns just beyond the near-term period
on Thurs. As such, a High Wind Watch remains in effect for Avery
County from late Wed thru Thurs aftn. The SWLY winds will bring
warmer air from the Deep South, allowing temps to rebound a decent
amount this afternoon, especially over the NC mtns, although highs
should still remain a few deg below normal for early December.

&&

.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
As of 145 PM Tuesday: A vigorous 500 mb shortwave will swing thru
the Great Lakes Wednesday night. An associated cold front will
drop SE thru the Ohio Valley and bring a 50-kt westerly 850 mb jet
across the NC mountains overnight into Thursday. The winds start
out west-southwesterly, and gradually veer to west-northwesterly
by 12z Thu. So not an ideal direction for a mountain-wave high
wind event, but strong CAA may allow for 50-60 mph gusts across
the northern mountains above 3500 ft. Since most of Avery is
above 3500 ft, will issue a High Wind Watch for Wednesday night
thru Thursday aftn. Confidence is too low for anywhere else in
the CWFA attm. Nevertheless, it will be windy during that period
across most of the mountains. There will be a very brief shot of
moisture with the front that may result in some snow showers along
the TN border mainly Wednesday night. Moisture quickly dries out
within the 850 mb flow Thursday morning. The front will bring temps
back down well below normal in the mountains, but with downslope,
temps will actually be a little warmer east of the mountains,
but still below normal. Cold sfc high pressure quickly builds in
Thursday night, with winds becoming light and skies clear. Lows
expected to get into the teens across all the mountains and even
into the NC Piedmont, low 20s elsewhere. Winds should become light
enough to keep wind chills above advisory criteria (-5 F in the
NC mountains), except for the highest peaks.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
As of 200 PM Tuesday: The medium range starts out cold Friday
morning, with the center of arctic high pressure settling over
the Southeast. Highs Friday expected to 10-15 deg below normal,
despite sunny skies. From there, the pattern will change with
the eastern CONUS trough finally swinging out to the east and
heights building in from the west. By Sunday, upper ridging will
set up across the eastern CONUS with split flow in the West. The
deterministic guidance still having some trouble agreeing on the
individual shortwaves upstream of the ridge, but with potential
southern stream energy ejecting out of the Southern Plains toward
the end of the medium range. Gradually increasing return flow atop
the forecast area will allow for a nice warming trend over the
weekend, with slightly above normal temps by Monday. The latest
NBM seems too quick in ramping up PoPs within the return flow
regime. For now, have kept them mostly in the chc to low-end likely
range starting Sunday night. By the onset of any mentionable PoPs
temps are already getting too warm for any wintry precip concerns.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
At KCLT and elsewhere: VFR through the period, with just some
increasing mid and high-level clouds expected late today. Light or
calm winds this morning will become SW at around 10 kts at most
sites by early afternoon. Some gusts in the 15-20 kts range will be
possible. SW winds are forecast to steadily increase Wed night, with
some gusts of around 20 kts becoming likely after midnight.

Outlook: A cold front will cross the area Thursday, bringing small
precip chances and possible restrictions to the mtns Thu morning.
Winds will become W/NW and increase Thu morning, with very gusty
conditions possible, especially at  KAVL and KHKY. Dry high pressure
will return on Friday and linger thru Sunday.

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...High Wind Watch from this evening through Thursday afternoon
     for NCZ033.
SC...None.

&&

$$

SYNOPSIS...DEO
NEAR TERM...JDL/JPT
SHORT TERM...ARK
LONG TERM...ARK
AVIATION...JDL