sc discuss
Office: CHS
FXUS62 KCHS 091319
AFDCHS
Area Forecast Discussion
National Weather Service Charleston SC
819 AM EST Tue Dec 9 2025
.SYNOPSIS...
High pressure will extend across the region for much of the
week. A cold front will push offshore Thursday morning with
another cold front possibly moving through late in the weekend.
&&
.NEAR TERM /THROUGH TONIGHT/...
Today: Aloft, the pattern will be broadly cyclonic as low
amplitude troughing covers the southeast and south-central
CONUS. At the surface, high pressure will start the day
stretching from New England, across the Southeast, and into the
lower MS Valley. This high pressure will then persist across the
Southeast and settle nearly right on top of the forecast area
by the end of the day. With plentiful dry air (precipitable
water values ~0.25") and no forcing, the forecast is dry. The
main change today will be the long awaited scattering any
lingering low stratus this morning followed by full sun in the
afternoon. While the return of the sun will certainly be
welcomed, it does not mean it will be a warm day. Instead low-
level thickness values support another very chilly day. Forecast
highs are for upper 40s across southeast SC and upper 40s and
low 50s for southeast GA. Such values would be on the order of
15 degrees below normal.
Tonight: With high pressure on top of the forecast area and
clear skies, we should see good radiational cooling conditions
tonight. This will yield lows solidly in the upper 20s inland,
with a transition zone from low to mid to upper 30s as you get
closer to the immediate coastline.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
Dry high pressure will prevail through the period.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
Guidance has continued to delay the passage of the strong cold
front, now showing it moving through late Sunday and maintaining
relatively warm temps over the weekend.
&&
.AVIATION /13Z TUESDAY THROUGH SATURDAY/...
The 12z TAF period begins with widespread MVFR stratus across
the forecast area including KCHS, KJZI, and KSAV. The main
forecast challenge will be timing when the stratus will finally
scatter out and conditions return to VFR. Based on the solid
appearance of the stratus on satellite imagery it will likely
take some time. Current thinking is it will first occur at KSAV
by the late morning, followed by KCHS and KJZI in the early
afternoon.
Extended Aviation Outlook: VFR.
&&
.MARINE...
Winds and seas have subsided enough to cancel the Small Craft
Advisory for the South Santee-Edisto Beach nearshore and Georgia
offshore legs.
Through Tonight: Winds will steadily diminish through the day,
becoming 5-10 knots by sunset for much of the local waters.
Overnight, winds will be around 5 knots out of the northwest and
becoming more westerly with time. Seas will start off the
morning in the 3-5 ft range and lower slowly through tonight.
Wednesday through Saturday: Brief Small Craft Advisory
conditions expected for most waters late Wednesday afternoon
through Wednesday night.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...None.
&&
$$
Office: CAE
FXUS62 KCAE 091126
AFDCAE
Area Forecast Discussion
National Weather Service Columbia SC
626 AM EST Tue Dec 9 2025
.SYNOPSIS...
Cool and cloudy conditions with chilly temperatures expected
tonight, into the 20s for most. Dry conditions are then
anticipated for the mid to late week period with near to
slightly below normal temperatures. A colder air mass may move
in behind a dry cold front early next week.
&&
.NEAR TERM /THROUGH TONIGHT/...
Key message(s):
- Continued cool with below normal temperatures
A drier air mass continues to build into the forecast area with
northwesterly flow aloft. PWATs will be around 0.25 inches through
the day today while low level cool and dry advection continues as
surface high pressure builds into the southeastern states. There
will be a passing shortwave during the afternoon but with such
limited moisture available no precipitation is expected. Widespread
low clouds in stratus expected to linger over the region through
late morning before breaking up in the afternoon. Northerly flow and
the cloud cover will keep high temperatures below normal with highs
expected in the 40s. Clearing skies should provide strong
radiational cooling conditions tonight and expect lows to fall into
the 20s to lower 30s, although the HRRR is showing some stratus
redevelopment and if this happens it could limit cooling.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
Key message(s):
- Breezy and warmer on Wednesday.
- Sunny and slightly cooler on Thursday.
Wednesday and Wednesday Night: A potent upper trough moves from
the Great Lakes region southeast into the Mid-Atlantic, passing
mostly north of the FA. Winds will be out of the southwest
resulting in warmer, albeit still below normal, daytime
temperatures with highs in the mid to upper 50s. There will
likely be a few clouds around, especially across the Northern
Midlands which will be closer to the upper support but a dry day
is forecast for the entire region. The big story on Wednesday
will be the winds which could gust into the 20-25 mph range,
higher on area lakes. If trends continue, a Lake Wind Advisory
may be required with a future forecast package. Surface winds
shift from southwest to northwest by daybreak in response to
approaching high pressure. Temperatures should radiate
effectively at night with lows in the mid to upper 30s.
Thursday and Thursday Night: The shortwave departs the region
early in the day with broad longwave troughing setting up. At
the surface, winds will be generally light and variable as high
pressure moves overhead. Temperatures should be slightly cooler
than Wednesday due to Cold Air Advection with forecast highs in
the lower to mid 50s. Clear skies and light winds will result in
temperatures falling into the upper 20s to lower 30s by daybreak
Friday.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
Key message(s):
- Temperatures warm to near normal values this weekend.
- The passage of a dry cold front on Sunday may usher in much
colder air early next week.
An upper trough will remain the dominant upper feature over the
Eastern CONUS during the extended. At the surface, high pressure
shifts offshore early Friday but should keep the region dry
through at least Saturday. The latest guidance now shows a dry cold
front crossing the FA on Sunday with much colder air moving in
early next week. This is a significant shift from the previous
forecast which showed the frontal passage on Friday. The new
forecast calls for slightly below normal daytime temperatures
on Friday and near normal temperatures Saturday and Sunday,
though the latter will depend on the timing of the dry cold
front. Bottom line is much uncertainty remains during the latter
portion of the long term but it appears the weekend will be
warmer than previously anticipated.
&&
.AVIATION /11Z TUESDAY THROUGH SATURDAY/...
Widespread low clouds expected through late morning with high
confidence in MVFR restrictions.
Stratus clouds continue to build southward through the Midlands with
cold advection as high pressure builds in. Expect MVFR cigs to
persist and remain in place through late morning before mixing
out early afternoon with cigs returning to VFR after 20z. Winds
will be from the northeast but generally remain light around 5
to 6 knots or less this morning before becoming light and
variable this afternoon as the surface high settles overhead.
The HRRR is an outlier showing a return of stratus tonight but
with all other guidance not showing this decided to keep an
optimistic forecast.
EXTENDED AVIATION OUTLOOK...No significant aviation restrictions
expected. Breezy conditions are possible on Wednesday.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...None.
GA...None.
&&
$$
Office: GSP
FXUS62 KGSP 091131
AFDGSP
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
631 AM EST Tue Dec 9 2025
.SYNOPSIS...
Dry high pressure will move in from the west through the middle
part of the week. A series of two cold fronts will move across the
region during the latter half of the week and weekend, ultimately
bringing much cooler temperatures into early next week.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 1:15 AM EST Tuesday...
Key Message 1: Drier conditions return overnight, however slippery
roads will be a concern thru the morning for areas that received
accumulating snowfall.
With low temperatures in the upper teens to low 20s this morning,
any melted snow or lingering snow cover could result in slippery
roads. A Special Weather Statement (SPS) will likely be issued for
lingering black ice thru this morning. Low temperatures are expected
to bottom-out below 30 degrees for the majority of our fcst area
this morning.
Key Message 2: Sfc high pressure gradually builds in from the north
today, bringing dry and cool conditions and gradually diminishing
cloud cover.
Temperatures should rise above freezing by mid to late morning for
most locations allowing the concern for slippery roads to diminish.
Although cloud cover will gradually thin/sct out thru the day, the
latest model guidance continues to suggest that it may take longer
than previously expected, and we may not see much sunshine until the
late afternoon at many locations. As such, high temperatures will
likely remain 10 to 15 degrees below normal across most of our CWA.
Highs will probably recover more over the southern and central NC
mtn valleys, however the northern NC mtns will likely struggle to
warm much above the mid 30s today. Outside the mtns, highs in the
upper 30s to low/mid 40s are expected.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
Key Messages:
1) Strong wind gusts Wednesday, especially over the mountains.
2) Better chances of precipitation on the TN border late
Wednesday/Wednesday night behind an initial cold front.
As of 1239 AM EST Tuesday: The greatest concern through the
middle part of the week continues to be the wind gust potential
on Wednesday. The synoptic situation hasn't changed much over the
past day, and the model guidance continues to show a strong low
level jet translating east across the region during peak heating
ahead of a short wave digging down into the mid/upper trof to our
west. Probably the biggest difference in the model guidance has to
do with how deep the mixing will be. The GFS and HREF would suggest
mixing deep enough to really tap into the low level jet and have
enough potential momentum transfer to bring down wind gusts that
would be close to Advisory level, especially above 3500 ft. However,
the NAM is not nearly as deep and has gust potential much more
in line with the model blend and below criteria. Fortunately,
we have another model cycle or two to evaluate the potential
and to see if the NAM and some of the other CAMs have the better
mixing/gust potential.
The other development in the new guidance is a trend toward better
precip chances late Wednesday through Thursday morning along the
TN border. Most of the guidance shows a more coherent sfc boundary
driven through by the short wave late in the day, with an area of
low level moisture moving in behind the front on a developing WNW
low level flow. We end up with a chance of precip in the upslope
areas near the TN border as a result, probably mostly a light
snow chance because of the cold advection on the west side of
the mtns. It should be a quick shot of precip though, limiting
any accumulations to maybe an inch in some spots, so well short
of Advisory level. The guidance brings slightly cooler air east
of the mtns with this development, so the high temps Thursday
have trended down a category or so, into the realm of five below
normal or thereabouts. Fair but cooler weather should continue
thru Thursday night with high pressure moving overhead.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
1) Arctic cold front delayed until Sunday, with a better chance
of precip over the mtns.
2) The cold air mass will finally arrive late Sunday into Monday,
with temperatures about 15 degrees below normal for Monday into
Tuesday.
As of 1252 AM EST Tuesday: The latest model guidance is doing that
moving target thing for the upcoming weekend, as it continues
to back away from any precip chances Friday and early Saturday
as the flow aloft flattens and any moisture/short wave energy
is directed more toward the central Appalachians. So, the fcst
precip probs have fallen off to a short period of slight chance
Friday night, and that might still be overdone. Not much change
is noted with temps for Friday with a flatter/stronger flow aloft
persisting longer into the weekend, however, a stronger wave moving
in from the west on Saturday results in a big upward bump in the
temps owing to some warm advection east of the mtns, to the point
where we have a decent shot to get a category or so above normal
for Saturday afternoon with some decent sun. Quite a change from
what the Saturday forecast looked like a few days ago. The latest
guidance has more of a moisture return from the western Gulf ahead
of the approaching wave, meaning there is more support for a band
of precip preceding what would be the Arctic cold front running
up the west side of the mtns Saturday night. Confidence is still
modest at this point and the QPF reflects that. Sunday no longer
looks quite as chilly as areas east of the mtns will still be in
the strong WNW downslope, so we might still be around normal, and
it will take until the overnight for the cold advection to work
its way across the mtns. But, it should eventually, and Monday
still looks fifteen below average. The air mass modifies quickly
and temps begin to rebound already Tuesday.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
At KCLT and elsewhere: Low-end MVFR cigs are expected to persist
thru the morning across the area, despite observing some holes in
the cloud cover over the past few hrs. Confidence remains fairly
low wrt how quickly these cigs will sct out today, but I still
expect VFR conditions to return to most terminals by mid to late
afternoon with few to sct mid and high clouds expected later this
evening and early Wednesday. Winds will remain light this morning
and generally favor a NE to ENE direction outside the mtns. They
will toggle around to S to SW this afternoon with speeds of 4 to
8 kts. They will eventually strengthen Wednesday morning as the
pressure gradient tightens over the region with low-end gusts
expected.
Outlook: Generally VFR conditions expected thru the end of the
week. Gusty SW winds are likely across the area on Wednesday.
NW flow precip may develop along the NC/TN border Wednesday
night and again Thursday night into Friday, however dry con-
ditions should continue elsewhere.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.
&&
$$
SYNOPSIS...PM
NEAR TERM...JPT
SHORT TERM...PM
LONG TERM...PM
AVIATION...JPT
