Area Forecast Discussion
Issued by NWS Columbia, SC
FXUS62 KCAE 222110
Area Forecast Discussion
National Weather Service Columbia SC
510 PM EDT THU SEP 22 2016
Upper level low will remain over the region tonight with a weak
surface low pressure along the coast. The upper low will weaken
and move away from the area late Friday into Saturday as an upper
level ridge builds over the region. A cold front will approach
from the north Sunday and stall over the region through much of
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
An upper level low over the eastern Carolinas will begin to weaken
overnight as surface low pressure lingers off the coast. This
combination will continue pushing moisture into the area with
showers expected through the day. Best chance of showers...and
isolated thunderstorms...will remain over the eastern Midlands
and Pee Dee areas where the coldest air aloft and deepest moisture
will reside. Majority of the showers will be diurnally driven.
Rain chances will diminish with sunset and be limited to the
eastern Midlands and Pee Dee region overnight. With extensive
cloudiness this afternoon...high temperatures will be in the
upper 70s to lower 80s. Overnight are once again expected to range
from the upper 60s to lower 70s.
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY NIGHT/...
The upper low that has been spinning across the eastern Carolinas
will continue to weaken and open during the day on Friday as an upper
ridge builds off to the west of the region. Should still be enough
moisture across the area through the day Friday to allow for some
isolated/scattered showers/storms to develop by the afternoon,
especially across the eastern counties. Models then indicating
that by Friday night, precip should begin getting pushed further
off to the east, closer to the coast and offshore, for the
remainder of the weekend. Have trended in that direction for the
weekend. A weak backdoor cold front will be nearing the region
from the north Sunday night, but limited moisture should keep
only isolated showers in the forecast Sunday night.
May still have some cloud cover around on Friday, which
would help keep temperatures in the middle 80s through the
afternoon. By Saturday and Sunday, expecting more sunshine through
the day, allowing temperatures to climb back above normal with
readings generally in the upper 80s to around 90 through the
weekend. Overnight lows generally in the middle 60s.
.LONG TERM /MONDAY THROUGH THURSDAY/...
Back door front will be stalling out south of the cwa on Monday.
Onshore flow pattern at low-levels will bring a chance of some
afternoon showers to the region through the period. There is some
uncertainty in the longer term forecast. Models diverge on the
upper pattern as we get into the middle of next week. The ECMWF
shows a flat pattern over the area as upper trough moves towards
the area from the Great Lakes. The GFS shows strong ridge with the
main axis off to the east of the area into Wednesday. GFS also
indicating a sharper upper trough off to the west moving towards
the region. Confidence in the longer term is rather low due to the
uncertainly. In general, slight chance/chance pops for each
afternoon looks reasonable. Near normal temperatures.
.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
Low pressure aloft will remain over the region through tonight before
weakening on Friday. This feature in addition to surface low
pressure along the coast will continue to promote scattered
showers through this evening. Expect coverage to diminish with
loss of heating this evening. Ceilings returned to VFR earlier
this afternoon, but model guidance suggests lowering again
overnight. Visibility restrictions will continue to be possible in
rain showers. Should see a diurnal trend with conditions improving
to VFR around the end of the TAF period.
EXTENDED AVIATION OUTLOOK...No significant impacts to aviation
expected Saturday/Sunday as drier air moves in, though late
night/early morning fog possible at the fog prone sites.