Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Columbia SC
508 am EDT Fri Oct 21 2016
a cold front will cross the area this morning. An upper-level ridge
over the southeastern states will weaken allowing an upper-level
trough to cross the region today through Saturday. Much cooler and
drier air will move in behind the front for the weekend.
Near term /until 6 PM this evening/...
early this morning...a cold front extending southwestward
through eastern Tennessee and Alabama will continue to approach
the forecast area from the west. Surface high pressure remains
over the area currently with generally clear skies. Clouds will
increase from the west toward daybreak ahead of the front. Patchy
fog has developed in the eastern portion of the forecast area but
should improve as winds pick up and clouds increase. Low
temperatures are on track, in the lower to mid 60s.
Today...an upper trough over the Mississippi Valley region will
continue to amplify and push a cold front through the forecast
area this morning. Moisture along the front appears to decrease
as it moves into the area given downslope northwest flow. Have
indicated slight chance pops across the north midlands this
morning with dry conditions further south. This is consistent with
hi-resolution models. By the afternoon, any showers will be
pushing off to the east with cold air advection and dry air
filtering into the area. Winds just ahead of and behind the cold
front will increase, becoming rather gusty through the afternoon
hours. Wind gusts between 20 and 25 mph will be possible with
higher gusts over area lakes. A lake Wind Advisory will be in
effect beginning at 21z this afternoon. Temperatures expected to
be at or slightly above normal as downslope flow offsets cold air
advection. Kept daytime highs a couple of degrees lower than
guidance, ranging from the lower 70s north and west to around 80
Short term /6 PM this evening through Monday night/...
tonight, cooler and drier air will be pushing into the region
behind the cold front. Winds will remain gusty in most areas.
Strong cold advection over warmer lake waters should keep the air
over the lakes well mixed overnight. Model soundings indicating a
strong low-level jet tonight, with winds between 30 and 40 knots
possible. Some of those stronger winds will have the potential to
be mixing down over area lakes, and a lake Wind Advisory will be
in effect through the overnight hours for the entire area.
Temperatures tonight will fall into the middle 40s, which will be
some of the coldest air so far this autumnal season.
Saturday through Monday night, cool and dry Saturday through
Sunday night. A noticeable change in temperatures will be felt
throughout the weekend. Even with plenty of sunshine, highs on
Saturday will not get out of the 60s. Lower 60s will be seen
across the Pee Dee and Catawba regions, with middle 60s in the
midlands, and possibly the upper 60s in the csra. Temperatures for
Saturday night will be even colder than the previous night.
Readings in the lower 40s, to possible the upper 30s, will be
felt. Winds will turn more out of the southwest on Sunday, which
will allow a little bit of a warmup. With good amount of sunshine,
readings will be back into the lower 70s for all areas. Better
return flow for Sunday night through Monday night ahead of another
approaching cold front will help moderate temperatures to start
off the work week.
Long term /Tuesday through Thursday/...
another cold front will be pushing east of the area by Tuesday
morning. With limited moisture once again, the front will come
through the area dry. Expect highs in the low to mid 70s and lows
in the mid 40s to lower 50s.
Aviation /09z Friday through Tuesday/...
a cold front approaching the region from the west will cross the
forecast area between 12z and 16z and will push east and off the
coast this afternoon. Ahead of the front early this morning, do
not expect a widespread fog threat due to increasing clouds and
light winds. However, fog has developed at fog-prone ogb, but
expect conditions to improve toward daybreak as clouds and winds
increase. Moisture appears limited so do not expect any rainfall
at the taf sites with the frontal passage. Winds will rotate from
southwesterly early this morning to northwesterly behind the front
by late morning. Winds just ahead of and behind the cold front
will increase with sustained winds around 15 knots and gusts
around 20 to 25 knots. Winds will remain elevated through the
overnight period and moisture will be limited, so do not expect a
fog threat early Saturday morning.
Extended aviation outlook...no significant impacts expected.
Georgia...Lake Wind Advisory from 5 PM this afternoon to 8 am EDT
Saturday for gaz040-063>065-077.
SC...lake Wind Advisory from 5 PM this afternoon to 8 am EDT
Saturday for scz015-016-018-020>022-025>031-035>038-041.