Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Columbia SC
215 am EDT Monday Jul 14 2014
weak high pressure will remain over the area today 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 /through tonight/...
a flat upper ridge extending from the Southern Plains into the
southeastern states will weaken early this morning 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. Expect early morning lows to be in the lower 70s.
A drier air mass will remain over much of the forecast area
through today. The upper level low over the Great Lakes 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 tonight. At the surface the cold front will move from
the Great Lakes region through the Ohio and Tennessee valleys tonight.
Across the forecast area ahead of the approaching system winds
will increase out of the southwest. There is a slight chance of
showers and thunderstorms across the area this afternoon into the
early evening. High temperatures today mainly 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/...
very few changes in the extended forecast. 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 /06z Monday through Friday/...
surface winds have remained up across the area early this morning
with a 20-25 knot low level jet in place. Satellite imagery also
showing continued high clouds moving over the terminals and this
combination of wind and clouds should limit and preclude predawn
fog development. There is a low chance of some possible stratus
developing before 12z but confidence is low.
The upper ridge will begin to weaken over the area today as an
upper trough dives into the upper Midwest and Great Lakes region.
Atmospheric moisture is increasing and there is a possibility of
isolated afternoon convection...but rain threat appears low with
instability remaining weak and trigger lacking. Chances are too
low to include in the forecast. Will include broken VFR ceilings
this afternoon. Winds will pick up from the southwest around 10
knots ahead of an approaching front.
Extended aviation outlook....a cold front will cross the area in
the Tuesday-Wednesday time-frame bringing widespread thunderstorms.