Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Columbia SC
321 am EDT Tuesday Sep 23 2014
weak front will remain along the coast as it weakens through
Thursday with an upper level closed low sitting over the area.
With northeasterly flow across the area and weak upper level
troughing chances of showers will continue through the week.
Near term /until 6 am this morning/...
upper level closed low has developed over the area. Front remains
stretched from the central SC coast through southern Georgia. With the
upper level low circulating overhead...expect the showers to
continue with a slow trend of diminishing toward daybreak. Showers
remain and stratiform in nature which should not pose a flooding
threat. Have increased temperatures and probability of precipitation slightly overnight...mainly
for the central and eastern midlands. Overnight lows will range
from the upper 50s over the western midlands to the lower 60s in
the eastern midlands.
Short term /6 am this morning through 6 PM Wednesday/...
NAM...GFS and European model (ecmwf) all dig a vigorous shortwave over the
southeast tonight which cuts off and remains over the Carolinas
and Georgia through Tuesday night. At the surface...high pressure
builds to the north and brings a long fetch of easterly flow off
the Atlantic over the southeast. For now have a northwest/southeast gradient in
the probability of precipitation with highest values over the southeast County Warning Area in the 20-30 percent range.
Lower probability of precipitation to the northwest in the 10-20 percent range. Limiting factor for
precipitation is drier air aloft. A blend of the guidance looks good for
Long term /Wednesday night through Monday/...
surface high pressure generally remains parked to the north through
the long range. Aloft the westerlies lift well to the north and a
weakness in the upper flow remains over the southeast US. Low level flow
with an easterly component will continue. Result is probability of precipitation above
climatology through the period generally in the 20-30 percent
range. With increased clouds...maximum temperatures will be below climatology
and min temperatures slightly above.
Aviation /07z Tuesday through Saturday/...
an upper level cutoff low has developed over the area which is
promoting light stratiform rain showers. Ceilings have dropped to
MVFR at ags and are expected to remain MVFR or possibly IFR
throughout the morning. Have seen some fluctuations between MVFR
and VFR ceilings at other taf sites early this morning. Generally
expect this trend to continue through daybreak as the upper low
rotates overhead. Northeast flow at around 5 knots during the
overnight period should hinder fog development. Winds will remain
out of the northeast through the day at around 8 to 12 knots.
Extended aviation outlook...restrictions possible during the
period associated with increasing low level moisture.