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000
FXUS62 KCAE 201642
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
1242 PM EDT Sat Apr 20 2024

.SYNOPSIS...
Moisture increases into Saturday as a cold front moves toward
the area. With strong heating each afternoon, diurnally driven
isolated showers and thunderstorms are anticipated to develop.
The front becomes stationary near or slightly south of the area
Sunday. Deep moisture and lift across the area will result in
numerous showers Sunday and Sunday night. Temperatures Sunday
and Monday are expected to be well below normal.

&&

.NEAR TERM /THROUGH TONIGHT/...
A weak surface trough and slow moving moisture-thermal boundary
continue to linger across the Southeast with westerly flow
aloft nearly parallel to the boundary. Only some scattered
strato- cu is pushing across the area as relatively dry air at
low levels is keeping any deeper convection from developing
early this afternoon. HREF members have trended slightly more
aggressive with potential convection later this evening as some
surface convergence and pressure falls occur along the surface
boundary in NC and SC. Forecast soundings generally develop
between 1000-1500 ML CAPE between 21z and 00z, generally along
I-20 and southeast; however, the HRRR and other HREF members are
extremely consistent showing a cluster of stronger storms near
the NC-SC border during this time, thanks to enhanced moisture
pooling due to stronger pressure falls and low development which
is line with current obs. Organized severe potential remains
fairly low in any convection that does develop as shear is
relatively weak and pulse severe is also limited as theta-e
depressions aloft are minimal thanks to relatively moist mid-
levels. Some an isolated severe storms remains possible later
this evening and SPC slightly expanded their marginal risk
accordingly.

The boundary will finally push south and east later tonight with
strengthening northerly, dry low level flow and corresponding
increasing 850-700mb moisture advection and isentropic lift. So
shower activity will increase as the boundary sags south
overnight into Sunday morning with wedge conditions beginning to
develop.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
An approaching shortwave trough over the MS Valley will promote
continued moisture advection and increasing isentropic lift as
the surface boundary sinks south of the area. Expect periods of
rain to overspread the forecast area through the day which
should strengthen in situ wedge conditions and result in
possible falling or near steady temperatures, which will be much
cooler than previous days with max temperatures ranging from
the upper 50s north to mid 60s south. Overall rain amounts
expected to be somewhat light ranging from around a quarter to
half an inch. Chances of rain decrease Sunday night as
isentropic lift weakens and shifts east of the forecast area and
deeper moisture shifts eastward with PWATs falling below an
inch. Any convection is expected to remain south of the forecast
area closer to the frontal boundary.

Drier air works into the region on Monday as the upper trough
axis moves over the region. There is a chance for afternoon
showers to develop in response to steep mid level lapse rates
from cold 500mb temps moving over the region but limited
moisture available will be a limiting factor and the best
chances should be closer to the Coastal Plain. Expect widespread
clouds to linger on Monday which will limit max temperatures
and keep them well below normal in the 60s. Clearing skies and
some cool advection should support cool temperatures Monday
night in the lower 40s.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
The extended forecast period generally remains unchanged with
dry weather expected during this period. 500mb ensemble means
show some weak height rises in the wake of the departing trough
off the east coast with somewhat zonal westerly flow.
Temperatures should be a bit warmer than Monday but still remain
below normal with highs in the lower to mid 70s.

A shortwave trough will move from the Great Lakes region to New
England and the Mid-Atlantic coast Wednesday and Wednesday
night. This will push a frontal boundary through the forecast
area by Thursday morning. Ensemble mean PWATs are forecast to be
near normal but with the Gulf of Mexico moisture cut off, most
of the moisture should be above 700mb and expect the front to
come through dry. Max temperatures will return to the upper 70s
to lower 80s on Wednesday ahead of the front with some
compressional heating and plenty of sunshine but highs on
Thursday will be slightly cooler again behind the front.
Ensembles show 500mb ridging on Friday although the GFS ensemble
is a bit flatter than the ECMWF ensemble.

&&

.AVIATION /16Z SATURDAY THROUGH WEDNESDAY/...
VFR conditions are expected through this afternoon. Evening
showers-storms possible, with deteriorating conditions Sunday
morning.

Some mid-level strato-cu likely this afternoon with light west
winds less than 10 knots. Showers and storms are possible later
this evening, after 21z, primarily at CAE-CUB-OGB but confidence
is too low for direct TAF mention for now; included VCSH from
this evening onward. Low VFR ceilings will push in behind the
boundary overnight into Sunday morning, but should remain VFR
through 09z Sunday at AGS-DNL and 12z at CAE-CUB-OGB before
dropping to MVFR. Widespread showers and some isolated
thunderstorms are also expected overnight starting after 06z at
all sites through the end of the TAF period. IFR cigs will then
likely develop by late Sunday morning for all sites and remain
down through the end of the period.


EXTENDED AVIATION OUTLOOK...High confidence in ceiling and
visibility restrictions Sunday night into Monday with wedge
conditions expected.

&&

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

&&

$$

SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...