542
FXUS62 KCAE 151035
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
635 AM EDT Sun Sep 15 2024

.SYNOPSIS...
There will be a chance of showers and thunderstorms each day
through early next week with deep moisture over the region.
Drier air may move into the region mid-week lowering rain
chances.

&&

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

- Mostly cloudy conditions.
- Periodic light showers are possible this evening.

Surface high pressure remains centered across New England, while
a developing area of sub-tropical low pressure will be off the
southeastern U.S. coast through tonight. This will keep a tight
pressure gradient and somewhat gusty winds across the region.
The developing surface low is forecast to track towards the
coastline of SC late tonight, but should remain offshore. The
surface high should prevail through the day, allowing only a few
isolated showers to move into the eastern cwa through the day.
Better moisture increase should occur overnight into early
Monday morning as the low moves closer to the coast. So, mainly
slight chance pops today and early tonight, then increase to
chance pops towards Monday morning across the east and
northeastern cwa. As for temperatures, below normal readings
will continue again this afternoon with highs mainly in the
lower 80s. Lows tonight fall back into the mid to upper 60s.

&&

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

- Periods of heavy rain possible Monday and Monday night

Low pressure is expected to move onshore between early Monday
morning to Monday night. Models continue to differ on the
strength and trajectory of this surface low. Ultimately this low
will be the main influence on the sensible weather for The
Midlands and CSRA in the short term. However, the uncertainty in
the exact strength and track lowers confidence in the amount
and location of any potential heavy rainfall. The most likely
area for rainfall will be across the Pee Dee region with lower
rain chances to the southwest. An isolated thunderstorm will be
possible but the steeper lapse rates should remain east of the
forecast area. Mostly cloudy or overcast skies and potential
rainfall should keep temperatures well below normal, in the mid
70s, for much of the area and upper 70s in the CSRA.

Moisture could linger across the region for Tuesday as the low
pulls away from the forecast area. A few showers will be
possible but overall rain chances are lower as the deepest
moisture shifts north.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
Key Message(s):

- Drier weather expected for mid-week
- Forecast uncertainty increases for late week

As a surface low moves north of the forecast area by mid-week,
relatively dry air is expected to wrap around the system and
move into the forecast area. Mean PWAT values from the GEFS and
ECMWF ensemble generally decrease through the week but remain
within 1.25 to 1.5 inches. With no strong forcing mechanism
expected through Thursday this should limit rainfall chances.
The pattern becomes more uncertain toward the end of the week
with ensemble members showing a larger spread in temps and
atmospheric moisture as mean 500 mb heights lower over the
region. So there will be at least a slight chance of showers and
thunderstorms through the extended. With drier air over the
region mid-week, we may see temperatures rise to near normal
with less cloud cover, otherwise below normal temperatures are
expected for daytime highs.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
MVFR ceilings will continue through the morning hours, then a
return to vfr expected by this afternoon. Potential again for
mvfr late tonight into Monday morning.

Developing surface low remains off the southeastern coast the
next 24 hours. Meanwhile, strong northeasterly wind flow
associated with an area of high pressure centered across the
Mid-Atlantic will continue. This will keep a tight pressure
gradient across the forecast area, and thus strong winds and
wind gusts will continue through the period at all sites.

Scattered showers remain closer to the coast, with a few
isolated light showers near the Midlands terminals this morning,
so can not rule out a brief passing shower through the period
at any site. Will include initial vcsh at cae/cub due to
regional radar showing light showers near those terminals. At
remaining sites, confidence not high enough to mention timing
at this time. Increasing rain chances possible near the end of
the 24 hour taf period as moisture from offshore surface low
moves further inland.

As for ceilings, mvfr conditions will prevail through about
noon. Guidance then shows improvement back to vfr after noon,
similar to the past several days. After sunset, mvfr ceilings
will then return towards 03z Monday.

EXTENDED AVIATION OUTLOOK...Scattered showers with possible
restrictions at times through Monday as moisture pools over the
area along a front and low pressure near the southeast coast.

&&

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

&&

$$