Mc Cormick, South Carolina Weather Forecast Discussion

073
FXUS62 KCAE 130024
AFDCAE
Area Forecast Discussion
National Weather Service Columbia SC
824 PM EDT Fri Sep 12 2025
.SYNOPSIS...
High pressure will dominate the weather pattern through the
next few days. Our next chance of rain might be early next week
but is dependent on the location and development of an upper
level low.
&&
.NEAR TERM /UNTIL 7 AM SATURDAY MORNING/...
Key message(s):
- None.
Upper trough axis over the area with surface high pressure
hanging on along and east of the Appalachians. PWATs remain
around an inch, although the highest dew points are closer to
the coast today compared to yesterday evening. With little
change in the synoptic pattern, expect similar low temperatures
to last night, possibly a degree or two lower with less of a
chance for stratus to develop over the area, although some low
clouds in the east will be possible.
&&
.SHORT TERM /7 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
Key message(s):
- Continued dry with seasonal temperatures.
Upper level trough is forecast to continue to dig into the
southeastern US, with prevailing northeasterly flow throughout
the atmosphere. The upper low is part of an Omega block present
across the CONUS, with anomalous ridging stretching into Great
Lakes and southern Canada, fostered by a strong shortwave trough
ejecting from the central Rockies and into the northern Plains
by Sunday night. ECE/GEFS 500 hPa mean heights indicate heights
over southern Canada at +2.5 SD for this time of year, which
should help dive our trough a bit deeper into the southeastern
US by Sunday night. Persistently tight pressure gradients are
the surface are expected over the coming days, with breezy
northeasterly winds 10-15 mph each afternoon. The airmass is
forecast to be very dry compared to normal, with PWs around
40-60% of normal. So while afternoon highs will likely be in the
mid 80s this weekend, the dry airmass should continue to foster
large diurnal ranges with lows in the upper 50s and lower 60s.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
Key message(s):
- Quiet weather expected through the period as troughing
  continues through the period.
- Rain chances may rise early next week depending on how the
  trough evolves
Omega block is expected to continue working itself to its
natural end point as we head into next week. This weekend`s
shortwave trough over the northern Plains should continue to
propagate into far southern Canada by early next week, forcing
continued amplification of the overall pattern. Canadian/ECMWF
guidance continues to point towards our deep trough cutting off
to the south of the anomalously strong ridging, forecast to be
centered over the eastern Great Lakes by early next week. The
GFS was more progressive with the trough, taking it out to sea
gradually, but the 12z run is falling in line with other global
models (FWIW the experimental, hi-res MPAS run by UCAR also
cuts off the trough). Based on pattern recognition and model
trends, thinking it is reasonable to expect that the low will
cut off and then meander westward through the middle of next
week before slowly working its way of the area. This has some
potential implications for sensible weather. If the low cuts off
and works as far west as the ECMWF suggests, we could see a
couple of days of rain next week as southeasterly, onshore flow
will become likely. However, thinking right now this is an
outlier and that we will stay mostly dry. Temperatures are
likely to be slightly below normal as the cut off low passes
overhead through the middle of next week. Anything beyond this
point is uncertain, as the progression and eventual placement of
the trough (or lack thereof!) will dictate the forecast beyond
Mon/Tues/Wed so confidence is fairly low in that period and
beyond.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
Prevailing VFR conditions expected through 00Z Sunday
Tonight, variable winds from 3 to 5 kts expected with clear
skies. A 20 kt LLJ will allow for decent mixing and hinder fog
development. Model guidance also suggests continued VFR
conditions, increasing confidence.
Persistent NE flow continues through the 24 hour TAF period.
Winds will pick up Saturday morning as a 20 kt LLJ mixed down
around 15Z leading to gusts up to 18 kts through the afternoon.
The air mass remains too dry for showers.
EXTENDED AVIATION OUTLOOK...A dry air mass will be over the
region this weekend with significant aviation restrictions
unlikely. The chance for restrictions increases early next week
as moisture deepens.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...None.
GA...None.
&&
$$

NWS CAE Office Area Forecast Discussion