Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Aberdeen South Dakota
321 am CST Friday Dec 13 2013
Short term...today through Sunday
Cold front continues to push south through South Dakota early this
morning with breezy northeast winds and falling temperatures in its wake.
Stratus deck is along the ND/South Dakota border and models suggest this
will slowly work its way south today. Temperatures will not rise much at
all today with the continued low level cold air advection and
cloud cover. Still expecting some light snow to develop/move into
northern portions of the County Warning Area later today...but models having a
tough time determining areal coverage and intensity. Soundings
show that the cloud layer today is pretty much entirely within the
snow growth region...but with only weak lift. There is currently
some light snow upstream across northern/eastern ND...so expecting
some of this activity to push south later today. Did not stray too
far from the probability of precipitation that were in the previous forecast given the
uncertainty of how this light snow will evolve later today.
Accumulations will be rather light.
Focus will then shift to Sunday as a rather impressive warm front
begins its trek eastward across the Dakotas. There are some model
differences in just how far east the warm front penetrates the County Warning Area
through the day Sunday...but tended to be a bit more pessimistic
on its travels. For sure it appears central and western South Dakota will
enjoy a rather mild day on Sunday with highs in the 30s and 40s.
The eastern County Warning Area will not experience the mild temperatures quite yet on
Sunday and will have to wait until Monday until the warm front
finally clears the County Warning Area. Models also showing some light snow out
ahead of this warm front so have some chances in the forecast for
the eastern County Warning Area on Sunday.
Long term...Sunday night through Friday
Models are in good agreement at the start of the period bringing a
clipper system across the far northeast County Warning Area. By Monday a ridge
building along the Pacific coast will help shift the upper trough
just slightly east...enough to squeeze in some warm air advection into the
plains even with continued northwest flow aloft. Surface temperatures will
warm nicely on Monday and may even pop above freezing for much of
A surface low moves into the plains toward the end of the week. Models
diverge on quantitative precipitation forecast and timing solutions with this system so for now
stuck with allblend for probability of precipitation. Temperatures will cool off again with and
behind this low with overnight low temperatures expected to be well below
zero by Thursday and Friday.
06z tafs for the kabr...Katy...kpir and kmbg terminals
VFR conditions will slowly be replaced by IFR/MVFR stratus clouds as
an Arctic boundary drops into the region. Light winds will come
around to the northeast and increase some through the overnight
and Friday as the boundary moves through. Since the stratus will
be in the snow growth region...periods of light snow will be
possible for all terminals except kpir by late morning. Kpir should
begin seeing light snow by late afternoon.