Area Forecast Discussion
Issued by NWS Columbia, SC
FXUS62 KCAE 230238
Area Forecast Discussion
National Weather Service Columbia SC
938 PM EST Sun Jan 22 2017
Numerous showers are expected overnight associated with strong
area of low pressure. The low will begin to lift north of the
region Monday. Dry ridging will move into the area Tuesday.
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
The severe thunderstorm threat has diminished as the instability
has weakened due to previous rainfall and loss of heating. The occluded
front will shift north of the forecast area overnight Wrap-around
moisture and cold air aloft associated with the upper low
supports a continued chance of showers. The deeper moisture
will push northeast of the area with precipitable water values
dropping below an inch.
Mixing associated with strong instability plus the pressure
gradient tonight supports a lake wind advisory.
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
The deep low will be lifting to the northeast and slowly filling
during the day Monday. Wrap-around moisture and cold
temperatures aloft will support scattered showers mainly during
the afternoon although showers may linger in the North Midlands
late in the day. Graupel will be possible because of the cold
air aloft...-20C to -25C at 500 mb. The models were not
consistent with the wind speed forecast Monday into Monday night
with the NAM MOS showing the higher values. Based on the
pressure gradient associated with the strong low north of the
area and forecast consistency we believe a lake wind advisory is
needed. It should be dry with less wind Tuesday as ridging
moves into the area. The temperature guidance is likely too high
Monday because of the cold upper low close to the
area/considerable cloudiness. Followed the consensus for the
temperature Monday night and Tuesday.
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
A cold front is forecast to push through the forecast area
Wednesday night or early Thursday supporting a chance of
showers. Much cooler yet seasonable temperatures will follow
this front for Friday and Saturday.
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
Strong low pressure system crossing the region through Monday
afternoon. Will see periods of widespread restrictions this
evening then again Monday morning.
Convection affecting all TAF sites should lift northeast of AGS/DNL
by 03Z and northeast of CAE/CUB/OGB by 05Z. Widespread cig/vsby
restrictions in convection. Moderate confidence in VFR/MVFR for
the overnight hours. The chance for showers and MVFR conditions
return by 12Z Monday as surface and upper level low crosses the
Surface winds will pick up area tonight to around 10 to 15 knots.
Wind gust 20 to 25 knots possible. Wind direction east to
southeast this evening becoming southwest overnight then veering
northwest Monday afternoon as the center of low pressure moves
east of the TAF sites. The chance for showers will end Monday
afternoon with clearing skies around the end of the TAF period.
EXTENDED AVIATION OUTLOOK...There will be chance of showers with
associated restrictions Thursday as a weak cold front crosses the
GA...Lake Wind Advisory until 7 PM EST Monday for GAZ040-063>065-
SC...Lake Wind Advisory until 7 PM EST Monday for SCZ015-016-018-