Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Columbia SC
342 am EST sun Nov 29 2015
weakening high pressure will remain in the forecast area through
today. A diffuse cold front will move into the area tonight and
stall. Another cold front will move through the area Wednesday.
Near term /through tonight/...
surface high pressure in the forecast area will continue to weaken
ahead of the slowly approaching cold front. The models display
the front moving into the forecast area tonight from the north. An
increase in moisture ahead of a middle-level shortwave trough
affecting mainly the north part plus weak 850 mb warm advection
supports a small shower chance in the northwest part late this
afternoon. The shower chance will increase tonight mainly in the
north part associated with convergence along the front...increased
850 mb warm advection plus some possible continued weak upper-level
lift. An average of the GFS and NAM MOS indicated categorical or
likely probability of precipitation in the north and chance in the south tonight. Leaned
toward the warmer temperature guidance today based on recent
verification in the air mass south of the front. Used the guidance
consensus for the temperature tonight.
Short term /Monday through Monday night/...
the NAM surface-based Li pattern suggests the diffuse wedge front
will push just south of the forecast area Monday and stall. The
models have been consistent keeping the deepest moisture and
upper-level lift north of the forecast area. The NAM...GFS...and
European model (ecmwf) were close with rainfall totals Monday and Monday night of
less than one-quarter of an inch in the south part and one-
quarter to one-half of an inch in the north section. Lowered the
high temperature guidance especially in the north part of the
forecast area because of The Wedge pattern. Used the guidance
consensus for the low temperature.
Long term /Tuesday through Saturday/...
the weak wedge front will likely lift north of the forecast area
Tuesday ahead of the approaching cold front. The GFS and European model (ecmwf) display
the front moving through the area Wednesday. The pattern supports
a continued shower chance. It may be dry behind the front Thursday
through Saturday...but wave development along the front near the
southeast coast may occur. The models generally keep deep moisture
southeast of the forecast area...but a tight moisture gradient and
past model runs indicating more moisture in the forecast area
indicates low confidence late in the medium-range period.
Aviation /09z Sunday through Thursday/...
low to moderate confidence in possible MVFR restrictions in fog
early this morning. Otherwise VFR conditions for much of today
into this evening.
Mainly scattered/broken high clouds at the taf sites early this
morning and throughout much of today. Winds will generally be
calm before sunrise...then light and variable later today. Middle and
high level clouds may deter fog formation this morning but for now will
mention high-end MVFR restrictions at all taf sites until around
13z-14z. As for clouds...they are forecast to become more
broken...lowering to near 10-12kft through the day. No rain
Extended aviation outlook...increasing chances of rain Sunday
night into Monday associated with a backdoor front. Wedge
conditions may develop Monday which could also lead to