Scientific Forecaster Discussion
Area forecast discussion...updated
National Weather Service Aberdeen South Dakota
653 PM CDT Tuesday Mar 11 2014
see below for an updated aviation forecast discussion.
short term...tonight through Thursday night
Main forecast challenges center around precipitation tonight...and
temperatures thereafter. Models remain somewhat consistent with a
fairly weak pv anomaly traveling south across the eastern Dakotas.
Time heights and model uvm not particularly impressive but given
model consistency and weak tropopause fold...will continue chance mention
of rain/snow across the region. Not expecting anything more than
an inch at best with this system. The rest of the period looks
As for temperatures...the next couple days should feature a warm
up...especially Thursday. On Wednesday a warm front will be edging
east across the County Warning Area...but may not make it all the way to the
eastern County Warning Area. However...on Thursday we should be solidly in the
westerly and southwesterly flow in the boundary layer with decent
mixing expected. Did bump up highs a bit both Wednesday and
Thursday from previous forecast.
Long term...Friday through Tuesday
There is a reasonable agreement among models with the evolution of
the upper level flow pattern across the Continental U.S. Through the period.
Persistent northwest flow aloft will dominate the weather pattern
for the northern plains. A series of clipper systems passing either
through or northeast of the region will bring a wide range of
weather conditions. Any clipper system passing through the
region will bring mixed precipitation based on thermal profiles. Any system
passing northeast of the region will likely bring above normal
temperatures. A lack of agreement among models with timing and
placement of clipper systems has led to a low forecaster
00z tafs for the kabr...Katy...kpir and kmbg terminals
At the moment...all four terminals are observed in VFR conditions.
Kpir and kmbg will likely spend the next 24 hours in VFR weather
conditions. However...Katy could see some 2500ft-3000ft above ground level ceilings
spread over terminal space within the next couple of hours and
stick around for several hours. Both the kabr and Katy terminals
are currently forecast to see ceilings developing and lowering into at
least MVFR range at or after 06z tonight when a weak low pressure
system moves south through the Dakotas. Confidence is high enough
to carry some light snow mention at these two
terminals...including a prevailing IFR visby in light snow for
several hours...mainly between 06z and 15z. On Wednesday...all
four terminals should come into a westerly surface wind /out west
first and then by afternoon out east/...which should keep
kpir/kmbg in VFR conditions...and which should signal the
improvement of flight category at kabr and Katy into VFR as well.
long term...South Dakota