Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Columbia SC
826 PM EDT sun Jul 13 2014
weak high pressure will remain over the area through Monday with a
cold front approaching the area by Tuesday morning. The front will
increase chances of showers and thunderstorms Tuesday through
Wednesday afternoon. The front will stall to the south on Wednesday
and lift back northward into the area on Friday providing additional
showers and thunderstorms.
Near term /tonight through Monday night/...
a flat upper ridge extending from the Southern Plains into the
southeastern states will weaken overnight as a trough deepens
across the Great Lakes region and Ohio Valley. Surface high
pressure ridging across the area from the western Atlantic will
move east overnight. A drier air mass will remain over much of the
forecast area through Monday. The upper level low over the Great
Lakes Monday morning will begin diving southward along with cooler
air behind it. As the weak high pressure continues to move away
from the region...the upper low with associated trough will push
into the MS River Valley Monday night. At the surface the cold
front will move from the Great Lakes region Monday morning through
the Ohio and Tennessee valleys Monday night. For Monday across the
forecast area ahead of the approaching system winds will increase
out of the southwest to the region. Clouds will increase by Monday
afternoon. Low temperatures tonight should fall into the low 70s
with high temperatures on Monday in the middle 90s.
Short term /Tuesday through Tuesday night/...
by Tuesday morning the cold front will be moving into the upstate.
As the upper level trough deepens and pushes into the eastern US
Tuesday afternoon...the cold front will cross the forecast area.
Although the true colder air will struggle to reach the area
dynamics with the front will be strong enough to support
thunderstorms...with the main concern for possible strong
thunderstorms over the northern midlands Tuesday into Tuesday night.
The front will move toward the coast late Tuesday night with
slightly cooler and drier air trying to cross the mountains. Daytime
highs with more cloud cover will be in low 90s Tuesday. Overnight
lows will be in the lower 70s.
Long term /Wednesday through Sunday/...
models are in good agreement through the long term with the GFS
being stronger than the European model (ecmwf) late in the period. The front will
stall across northern Florida late Wednesday with a weak low pressure
developing over central Texas. This will leave slightly cooler and
drier air over the region Wednesday and Wednesday night with the
front beginning to return northward Thursday as the disorganized
low tracks across the Gulf states. This will bring increasing
chances of showers and thunderstorms to the area. The front will
again stall across the area late Friday through the weekend
continuing the chances of showers and thunderstorms. Temperatures
through the long term will be slightly below normal through Friday
then return to near normal for Saturday and Sunday.
Aviation /00z Monday through Friday/...
showers and thunderstorms have been confined to the coast. Expect
some middle and high level clouds through 06z. Fog threat appears
low due to strong...20kt low level jet development toward morning.
Some stratus or strato-cumulus may develop toward daybreak but
confidence low. Latest lamp guidance suggesting brief period of
MVFR at ogb and ags otherwise VFR. Scattered to broken cumulus
during the day Monday...rain threat appears low with instability
remaining weak and trigger lacking.
Extended aviation outlook....a cold front will cross the area in
the Tuesday-Wednesday time-frame bringing widespread thunderstorms.