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660
FXUS62 KCAE 201519
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
1119 AM EDT Fri Sep 20 2024

.SYNOPSIS...
High pressure and ridging build into the area today, bringing
warmer temps and limiting rain chances to mainly the northern
Midlands. Dry and warm conditions continue through Sunday, then
become more seasonable early to mid week.

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

- Warming trend begins today with just isolated showers across
  parts of the northern/central Midlands.

The axis of an upper trough has shifted just to our east as
ridge builds in from the southwest, putting us into a northwest
flow regime. At the surface, high pressure continues to filter
in from the north. The upper ridge and trough are expected to
drift eastward through the day as the surface high pushes
southward. As a result, a generally dry and warm day can be
expected for much of the area. The one fly in the ointment is
that a weak shortwave within the northwest flow could be just
strong enough to bring a slight chance (~15%) of few showers or
an isolated thunderstorm to the northern and central Midlands
this afternoon. After daytime heating wanes, the chance for any
precipitation diminishes. Afternoon highs are expected to be a
few degrees warmer than Thursday, while overnight lows should be
similar to Thursday night.
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&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
Key Message(s):

- Upper ridge builds over the area this weekend with warming temps

Upper ridging centered over the OH/TN Valleys will build over
the Carolinas this weekend as an upper trough over the four
corners region lifts northeastward toward the Central Plains.
Surface high pressure centered over New England and the Mid-
Atlantic will continue to ridge into the Carolinas through the
weekend. There is the possibility of isolated showers developing
in the northwesterly flow aloft late Saturday but moisture is
limited with PWATs around 1.2-1.5 inches.

Most guidance keeps any showers north of the forecast area, so
will continue to carry a dry forecast. Forecast soundings show a
strong subsidence inversion which should further limit
instability and rain potential. 850mb temperatures rise a few
degrees over the weekend and expect highs to be near to above
normal Saturday and above normal on Sunday. NBM probabilities of
max temps greater than 90 degrees on Sunday are over 50 percent
across much of the southern half of the area.

&&

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

- Generally benign weather with near to above normal temperatures
- Chances of rain increase on Wednesday with limited confidence

Ensemble guidance shows positive 500mb height anomalies with an
upper ridge remaining over the Carolinas into midweek with high
pressure in control at the surface but shifting offshore by
Tuesday. This should lead to continued warm temperatures with
highs in the mid 80s to low 90s. More uncertainty arrives in the
forecast by midweek as ensembles and deterministic models
handle a potential tropical system moving into the Gulf of
Mexico near the end of the forecast period.

The GFS and its ensembles are a bit deeper with the next upper
trough moving through the Ohio Valley on Wednesday which picks
up a system moving into the Gulf, while the EC and its ensembles
are less amplified and do not have that system in the Gulf of
Mexico until later in the week beyond the forecast period.
Regardless, moisture increases over the region and low chances
of rain return to the forecast on Wednesday. Temperatures
expected to remain above normal but cool a bit by mid week with
the approaching upper trough.

&&

.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
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VFR conditions expected for much of the period.

VFR conditions are expected to prevail through most of the
forecast period. Light northeast winds expected today, then
diminish and shift more easterly after about 00z.

EXTENDED AVIATION OUTLOOK...No significant impacts to aviation
expected through Tuesday.
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&&

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

$$