Columbia, South Carolina Weather Forecast Discussion

115
FXUS62 KCAE 282345
AFDCAE
Area Forecast Discussion
National Weather Service Columbia SC
745 PM EDT Sun Sep 28 2025
.SYNOPSIS...
Increasing moisture will allow shower chances to return late
tonight. Locally heavy rainfall remains possible to start the
week as moisture remains over the region through Tuesday. Later
in the week, high pressure moves into the region, bringing cool
and dry conditions to the area.
&&
.NEAR TERM /THROUGH TONIGHT/...
Key message(s):
- Cloudy conditions with isolated showers overnight.
- Increasing rain chances from the east later tonight.
Although Tropical Storm Imelda is now forecast to remain well
southeast of the region as it moves northward off the FL east
coast and through the Bahamas tonight, it will still have a
minor impact on our forecast area overnight. This will be in the
form of plenty of mid and upper level cloud cover that will be
streaming northward from the Tropical Storm, along with some
moisture moving inland late tonight from the Atlantic bringing
an increase in rain chances towards morning across the eastern
counties. At the surface, a northeasterly wind pattern will
continue through the night, keeping a slight wedge flow in
place. As the moisture moves inland from the east overnight and
rides over the northeasterly low-level flow, expect more
widespread low clouds to develop towards sunrise. Temperatures
should fall into the mid to upper 60s by daybreak.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
Key message(s):
- Cloudy, cool, and rainy conditions expected as moisture
  increases northward from TS Imelda.
- Increasing confidence in less impacts associated with TS
  Imelda including less rainfall with totals expected between
  0.5-1.5 inches.
Guidance continues to trend more to a solution that results in
decreased chances of impacts in our area associated with TS
Imelda. The cyclone remains weak at this time but is still
forecast to drift northward through The Bahamas and become a
hurricane as it encounters more favorable conditions by Monday.
A significant plume of moisture with PWATs 150-175 percent of
normal is expected to move over the forecast area on Monday. The
combination of this anomalous moisture and increased low level
convergence should result in periods of moderate to heavy
showers moving through the area on Monday. Instability will be
limited but cannot totally rule out thunderstorms, though they
are expected to be isolated. Rainfall amounts have decreased a
bit but any rainfall will be beneficial at this point and the
highest amounts should favor the eastern portion of the forecast
area with amounts ranging from a tenth to half inch in the west
to around 1-1.5 inches in the east. The best rain chances
appear to be Monday through Monday night. Widespread clouds and
precipitation will also significantly limit daytime heating and
high temperatures are expected to be 5 to 10 degrees below
normal with highs in the 70s, although some locations may
struggle to get out of the 60s due to rainfall.
Latest ensemble guidance has trended stronger towards TS Imelda
lifting northward off the east coast of Florida and then taking
a right turn due to the influence of the much stronger Hurricane Humberto
approaching from the east and a strong surface high that builds
into New England and the Mid-Atlantic and ridges into the
Carolinas. Isolated to scattered showers will remain possible on
Tuesday but with cooler high pressure building in from the
north thunderstorms appear less likely and the highest rainfall
is generally expected to remain closer to the coast east of our
area. Temperatures will again be below normal with highs in the
70s. An increased pressure gradient should support breezy
conditions but no significant winds are expected with gusts
generally topping out around 25 to 30 mph.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Key message(s):
- Increasingly dry and cool conditions are expected through the
  end of the week.
The extended forecast period should feature generally fair
weather with below normal temperatures and a taste of Fall.
Guidance continues to be in agreement showing TS Imelda
shifting further to the east on Wednesday away from the region
as a reinforcing cold front pushes southward through the
forecast area Wednesday night. Decreasing moisture begins on
Wednesday as the deeper moisture shifts offshore in the wake of
Imelda and PWATs are forecast to fall back below normal (less
than an inch) Thursday through the end of the week with deep
northeasterly to northerly flow in place. Ensembles are showing
below normal temperatures at 850mb associated with the anomalous
high pressure riding down the east coast and below normal
temperatures are expected to continue through Saturday with
highs in the 70s and lows dropping into the 50s and 60s.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
High level clouds from Tropical Storm Imelda being slung
northward into eastern GA and SC at this hour which will
continue into the overnight. Also continue to deal with SCT-BKN
deck FL035-050 thanks to a stationary front along the Atlantic
Coast. Two main factors to the aviation forecast this evening.
The first is timing the waves for potential -SHRA beginning
around 10Z or so, a break in the late morning through mid
afternoon, and then more convective activity into the late
afternoon towards 00Z Tuesday. Use TEMPO to cover the morning
3-4 hour windows for this activity at terminals and then PROB30
for the potential after 20Z. TSRA possible through the forecast,
but only giving it a mention for the latter time frame when it
has a higher chance of occurring. The second aspect of the
forecast is the expectation for ceilings to drop in stratus down
to IFR, generally after 09Z Monday morning. Low ceilings will
then persist through the duration of the TAF period. Northeast
winds less than 10kts expected at the surface.
EXTENDED AVIATION OUTLOOK...Plenty of low-level moisture through
Wednesday will keep potential for restrictions in the forecast
into Wednesday, then drier air will begin to impact the region
through the end of the week.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...None.
GA...None.
&&
$$

NWS CAE Office Area Forecast Discussion