394
FXUS62 KCAE 250845
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
345 AM EST Mon Nov 25 2024

.SYNOPSIS...
The air mass across the region will continue to moderate today
with temperatures rising to above normal. A cold front with
limited moisture will move through the area Tuesday with a
scattered light showers. A stronger cold front will move
through the area Thursday to Thursday night with scattered to
numerous showers and isolated storms. Below normal temperatures
expected next weekend as the coldest air mass of the season
moves into the region.

&&

.NEAR TERM /THROUGH TONIGHT/...
Key Message(s):

- A cool morning with some patchy fog along area rivers.
- Mild day ahead of an approaching cold front.

Early this morning: Light low-level west/southwesterly winds
will keep some mixing going through sunrise. This will keep
morning lows in the low to mid 40s. May see some patchy fog
form once again along area rivers and lakes, but nothing
widespread.

Today and Tonight: Upper ridge axis moves through the region,
then offshore tonight ahead of an approaching upper trough. This
trough will be pushing a weak cold front towards the region
tonight. Ahead of it though, warm advection and plenty of
sunshine through the day will bring temperatures back above
normal once again. Highs expected to reach into the lower 70s
this afternoon. Into tonight, moisture will be on the increase
ahead of the cold front, but a mostly dry forecast expected for
much of the overnight hours. Best chance tonight for any
rainfall will not occur until after 06z towards 12z just ahead
of the cold front, and mainly over the very western counties.
Qpf amounts remain on the light side with the initial rain
chances. Lows tonight milder, with readings in the low to mid
50s.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
Key Message(s):

- Warmer weather Tuesday ahead of a cold front.
- Scattered light showers Tuesday associated with the front.

Cold front will be near the western portion of the forecast area
Tuesday morning with good agreement among global and hires
guidance in pushing through the area through the morning,
although it will likely slow as it approaches the Coastal
Plain. While upper level forcing will be weak, HREF mean
indicates PWATs increase to above 1.2 inches which combined with
surface convergence along the front, will support scattered
showers. Increased pops to chance (around 30 percent in the
western half of the area) with hires guidance consistent in a
broken line of showers moving through the area in the morning.
Rainfall amounts still limited with WPC ensemble blend
indicating a low probability (generally 25% or less) of total
rainfall exceeding a tenth of an inch. Warm advection ahead of
the front will lead to highs well above average, especially in
the southeastern portion of the area. Highs generally in the low
to mid-70s. Not a particular cold airmass expected behind the
front as high pressure pushes in from the west, where the
airmass had a couple days to moderate over the central CONUS.
Lows will be in the low to mid 40s.

Wednesday starts with zonal flow aloft with high pressure
centered to the north of the forecast area. As an upper trough
deepens to the west of the area, deep southwest flow is expected
to strengthen which will lead to moderate to strong warm, moist
advection across the area. Blended guidance favors a fairly
strong high temperature gradient as a result, with highs in the
low 70s in the south to low 60s in the north. Increasing clouds
through the day with the deep moisture increase. Precip chances
remain low until after midnight, with a more impactful
disturbance approaching the area towards the early morning hours
of Thanksgiving. Mild overnight lows in the low to mid 50s.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
Key Message(s):

- Scattered to numerous showers and isolated embedded
  thunderstorms for Thanksgiving with breezy winds.
- Significantly colder weather late week into next weekend.

The next more impactful system will approach the forecast area
early Thanksgiving. While there has been a pretty significant
split among GEFS and EC ensemble members, more GEFS members seem
to be converging on the EC ensemble solution. This favors a
strong cold front moving through the area the morning of
Thanksgiving. Numerous showers with embedded thunderstorms
likely associated with this front. A strong 850mb jet will be
associated with this system with NAEFS mean indicating 850mb
winds will exceed the 90th percentile and LREF mean between 45
to 50 knots. While uncertainty as to the degree of
destabilization, owing to the exact timing of the frontal
passage, EFI values for CAPE above 0.7 indicate unusually high
instability potential for this time of year. CSU machine
learning severe probs also have introduced severe storm potential
associated with the front as the potential for severe
thunderstorms continues to trend upwards. Outside of any
storms, winds will be breezy with blended probabilities of gusts
greater than 25 mph moderately high (40 to 50 percent).

Behind the front, a significantly colder airmass will settle
over the forecast area with a highly amplified trough over the
eastern US. Deterministic blended guidance remains well above
the 75th percentile of the distribution so likely not capturing
the extent of the cold for much of the area with NAEFS mean
850mb temperatures below the tenth percentile. Although notably
GEPS members are significantly colder than both GEFS and EC
ensemble members.

&&

.AVIATION /07Z MONDAY THROUGH FRIDAY/...
Mainly vfr through the period.

Airmass remains dry early this morning and through much of the
daytime hours. Enough moisture will exist near the warmer rivers
and lakes, so with the cooler overnight temperatures, some fog
formation will remain possible at kags this morning. Remaining
sites should remain fog free. Winds will be out of the
southwest less than 5 knots during the overnight hours, then
between 5 and 10 knots through the day. Moisture will be on the
increase late Monday night ahead of the front, but lower clouds
remain just west of taf locations through 06z, so vfr will
continue.

EXTENDED AVIATION OUTLOOK...LLWS conditions will be possible
Monday night ahead of the approaching cold front. The front will
move through the area Tuesday with light showers possible. A
stronger front will move through the area Thursday to Thursday
night with thunderstorms and gusty winds possible.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
SC...None.
GA...None.

&&

$$