Area Forecast Discussion
Issued by NWS Columbia, SC
FXUS62 KCAE 200804
Area Forecast Discussion
National Weather Service Columbia SC
304 AM EST Fri Jan 20 2017
A warm front in the forecast area this morning will lift north of
the area this afternoon. Another warm front will develop and move
into the region Saturday ahead of strong low pressure. The low will
be near the forecast area Sunday and Monday. The system will bring a
possibility of strong thunderstorms to the region Saturday and
.NEAR TERM /THROUGH TONIGHT/...
Scattered showers in the forecast area early this morning were
associated with isentropic lift just north of a warm front and a mid-
level shortwave trough. The models show the warm front lifting north
of the forecast area this afternoon with significant isentropic
upglide north of the forecast area today. Water vapor imagery
trends support the upper feature lifting northeast of the
forecast area early this morning and moisture should be shallow
in its wake. This trends support a diminished shower chance late
this morning and afternoon as supported by the high-resolution
models. There may be areas of fog near the warm front this
morning. It should be warm behind the front this afternoon. The
temperature guidance was consistent. Moisture should remain
shallow through early tonight with mid-level shortwave ridging.
The shallow moisture and nocturnal cooling may lead to area of
fog. Expect deeper moisture developing toward morning ahead of
another mid-level shortwave trough and warm front well south of
the region. The NAM and GFS MOS support chance pops in the
southwest section of the forecast area. The temperature guidance
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
There is a possibility of severe thunderstorms over the weekend.
The models display high moisture in the forecast area Saturday
through Sunday night. A warm front should be in area Saturday
and Saturday night. The front may lift north of the area Sunday
followed by a cold front and associated strong low pressure.
The models show strong shear. The NAM is more progressive with
the low and develops greater shear and instability Saturday
compared to the GFS and ECWMF. The slower timing is likely
better because of the cut-off nature of the system but there
still may be enough shear and instability for severe
thunderstorms mainly in the CSRA as early as Saturday. The
severe thunderstorm chance may be greatest late Saturday night
through Sunday evening. The GFS and ECMWF depict a strengthening
low-level jet Saturday night. The GFS depicts the greatest
instability Sunday closer to the approaching upper low. There
may also be a mid-level dry slot moving into the area Sunday.
The main limiting factor for severe thunderstorms may be
widespread showers helping to diminish instability or convection
south of the forecast area limited the transport of moisture
and instability northward. Followed the WPC rainfall forecast
with the heaviest amounts Saturday night and Sunday. Forecasted
weekend totals of 2 to 3 inches.
.LONG TERM /MONDAY THROUGH THURSDAY/...
The GFS and ECMWF display the upper low beginning to lift
northeast of the region Monday. Wrap-around moisture and
instability associated with the low supports a continued chance
of showers. Dry ridging should dominate Tuesday with an
approaching cold front Wednesday. The models show the front in
the area Thursday. The GFS depicts greater moisture along the
front compared to the ECMWF.
.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
Latest composite radar indicating some light showers moving into
the area from the west early this morning. IFR/MVFR cigs
possible until 16Z-17Z today although the showers should shortly
after sunrise. Should see conditions improving to VFR early
afternoon as the warm front lifts north of the area and
southwest winds increase to around 10 knots.
EXTENDED AVIATION OUTLOOK...Showers...and associated restrictions...
are likely Saturday through Monday as a low pressure system
crosses the region.