Scientific Forecaster Discussion
fxus62 kcae 121526
Area forecast discussion
National Weather Service Columbia SC
1026 am EST Tue Nov 12 2019
a strong cold front will push through the forecast area today.
Showers will accompany the front. The coldest air so far this
season will follow the front for Wednesday and Thursday with
temperatures well below normal. Rain may again develop Thursday
afternoon associated with low pressure developing just off the
Near term /through tonight/...
analysis at 10am revealed the cold front extended from near
Raleigh southwestward to Columbia to Augusta to near Macon.
Temperatures drop off significantly behind the front, already
falling into the lower 40s in Greenville with 30s in the
foothills of NC. Regional radar shows widespread rain extending
from central Virginia/NC into the forecast area but showers are more
scattered and lighter in intensity over our area. Total rainfall
expected is likely to be less than a quarter of an inch for most
High temperatures will likely occur before noon with falling
temperatures through the afternoon. Rain and clouds should begin
to clear from west to east during the afternoon hours as the
front pushes off the coast by this evening. Winds will pick up
behind the front, especially when clouds start to break up and
deeper mixing takes place with north winds 15 to 20 mph and
higher gusts. The Warm Lake temperatures will allow
strong winds to continue over the water through the night.
Therefore a lake Wind Advisory is in effect for this afternoon
Temperatures will continue to drop sharply overnight with
strong cold advection as Arctic high pressure builds over the
region. Winds will stay up limiting radiational cooling, but the
strength of this Arctic air will be enough to push low
temperatures well into the 20s, approaching daily records.
Short term /Wednesday through Thursday/...
Canadian high pressure will ridge into the forecast area from
the north through Wednesday night. It will remain dry with flat
The surface ridge will shift farther offshore Thursday. The
models show increased moisture in a more onshore flow along with
isentropic lift. The models have been consistent indicating a
trough developing near the coast as a mid-level shortwave trough
moves into the region. The GFS and European model (ecmwf) MOS pops have trended
upward and moisture may become deep enough for rain development
Thursday afternoon. We have increased pops. Rain amounts should
be light because of the initial dryness and weak lift.
Leaned toward the lower temperature guidance Wednesday because
of the cold air mass. Used the guidance consensus Wednesday
night and went a little lower than the model blend Thursday
because of a cold start and expected cloudiness during the day.
Long term /Thursday night through Monday/...
forecast confidence remains low because the models depict a
tight moisture gradient in the region and there has been
inconsistency with the placement and moisture associated with
low pressure forecast off the southeast coast Thursday night and
Friday. The GFS and European model (ecmwf) have trended higher with pops so we
have also increased the rain chance.
The GFS and European model (ecmwf) are in a little better agreement with the
bulk of moisture associated with the offshore low just east of
the area Saturday, but a tight moisture gradient diminishes
forecast confidence. We have maintained chance pops, highest in
the East Part.
The GFS and European model (ecmwf) are in agreement with dry conditions Sunday.
Low pressure is depicted farther northeast of the area along
with upper ridging in the region.
The models depict increased moisture with sharp upper troughing
and associated coastal low pressure returning Monday. Deepest
moisture may remain east of the area. A model blend supports
Model forecast soundings have been consistent indicating all-
liquid precipitation through the medium-range period.
Aviation /15z Tuesday through Saturday/...
deteriorating conditions into early afternoon with Arctic
frontal passage then improvement by this evening.
Cold front currently just east of all terminals except ogb and
should reach there by 16z. Cigs/vis lowering to MVFR/IFR behind
the front with some light rain showers. This will persist
through 20-21z then improve back to VFR by this evening as dry
and cold Arctic high pressure builds into the region. Winds
shift to the northwest behind the front and will increase in
speed to 10 to 15 knots with some gusts over 20 knots expected
After the frontal passages, skies will clear, but winds will
remain breezy through the night into Wednesday morning.
Extended aviation outlook...VFR Wednesday. Rain and associated
restrictions possible Thursday through Saturday.
Georgia...Lake Wind Advisory until 7 am EST Wednesday for gaz040-063>065-
SC...lake Wind Advisory until 7 am EST Wednesday for scz016-018-