Area Forecast Discussion
Issued by NWS Columbia, SC
FXUS62 KCAE 242044
Area Forecast Discussion
National Weather Service Columbia SC
444 PM EDT SAT SEP 24 2016
An upper level ridge will continue to build east into the area
through Sunday. A cold front will approach from the north Sunday
and stall across the area Monday providing a focus for scattered
showers and thunderstorms. Another cold front will approach from
the west Tuesday and move east of the area mid week. The air mass
behind this system will be drier and more seasonable.
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
A high amplitude upper level ridge over the Mississippi Valley
will gradually build east through tonight as an upper level cut-
off low over southern Georgia retrogrades westward. At the
surface, weak high pressure will remain over the region while a
backdoor cold front remains well to our north. Diurnal clouds
this afternoon expected to dissipate this evening. Dry air aloft
and near calm wind overnight will aid the development of patchy
fog late tonight. MOS consensus and persistence indicated
overnight lows in the mid to upper 60s.
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY/...
Amplified upper level trough over New England with surface ridge
building south. This will result in a back door cold front from
the northeast late in the day Sunday or early evening. Moisture
increasing through the day...although mainly low-level. Air mass
becoming weakly to moderately unstable ahead of the front. Strong
insolation again so temperatures around 90 in the afternoon.
Better chance showers in the north late into the evening...more
isolated south with frontal boundary convergence in the north.
With weak dynamics rainfall amounts late Sunday/Sunday night are
expected to be light with less than one tenth of an inch expected.
East low level flow on Monday...resulting deeper moisture. Frontal
boundary stalled across the area should support mainly diurnal scattered
showers and thunderstorms in a weakly to moderately unstable air
mass. Temperatures a little cooler Monday. MOS overnight minimum
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
Deep upper level trough over the Great Lakes Tuesday...amplifying
along the eastern seaboard Thursday. This system will drive
another stronger cold front through the area Tuesday into early
Wednesday as per latest GFS solution. Chance pops Tuesday into
early Wednesday, drying out from the west by late Wednesday
afternoon. Dry high pressure will build in from the north Thursday
through Saturday with near seasonable temperatures.
.AVIATION /21Z SATURDAY THROUGH THURSDAY/...
High confidence for VFR conditions through this evening.
Diurnal cumulus this afternoon with cloud bases at or above 4000
feet. Weak high pressure over the region this afternoon. Dry air
aloft combined with increasing low level moisture and near calm
wind will allow at least patchy fog to develop overnight. Have
indicated IFR at fog-proned AGS/OGB between 06Z and 13Z.
Confidence for fog development at other TAF sites too low to
include attm. A cold front will approach the TAF sites from the
north Sunday afternoon. Should see increasing clouds with bases at
or above 4000 ft ahead of the front. Winds generally northeast to
east less than 10 knots.
EXTENDED AVIATION OUTLOOK...Late night/early morning fog/stratus,
plus chance of showers/thunderstorms Monday through Tuesday Night.