Scientific Forecaster Discussion
Area forecast discussion...updated
National Weather Service Aberdeen South Dakota
746 am CDT Wednesday Mar 12 2014
12z aviation discussion updated below.
Short term...through Friday
A few light snow showers pushing across northeast counties this
morning...a mix of dendrites and snow pellets. Coverage is
limited...so will continue to advertise only 20 to 40 percent
chance. After this system moves through...upper ridge takes
charge and will be the dominant feature. H925 temperatures warm
past +8c today with a favorable mixing direction...though there
will be a drop off east of the Sisseton hills as cold air
retreats. Mild air continues into Thursday...with 850 mb
temperatures peaking about a Standard deviation above climatology.
Northwest flow and cold advection develops for Thursday
night...but favorable mixing will keep temperatures mild
overnight. 850 mb temperatures drop to around 0 to -5c
Friday...however favorable mixing conditions will continue which
will keep temperatures at or above average for Friday.
Long term...Friday night through Tuesday
the long term models show good agreement early on with divergence
in their solutions later on. The models show surface high
pressure centered in Canada with ridging nosing into the eastern
County Warning Area. The high pressure system in Canada and ridging into our County Warning Area
will build east and southeast into Sunday. Thus...Saturday and
for Sunday in the east look to be the only below normal
temperature days in the long term with mainly above normal
temperatures for Monday through Tuesday. A surface low pressure
area will slide down the east slopes of The Rockies for Saturday
and Saturday night. This looks like it will spread in some light
rain/snow into the County Warning Area. With the surface high pressure area
building east on Sunday...warm air advection clouds and some precipitation are
expected to affect the eastern part of the County Warning Area. Then the models
diverge on Monday and Tuesday with a short wave trough dropping in
from the northwest and its associated surface low pressure area.
By Tuesday...the ec showed a surface low pressure area in Kansas
while the GFS had the main low pressure area in the Great Lakes
region. At this time...have in more chances of rain/snow for
Monday into Tuesday as trending more towards the ec. Highs will be
mostly in the 40s and lower 50s for both Monday and Tuesday.
12z tafs for the kabr...Katy...kpir and kmbg terminals
Light snow flurries will end and the IFR/MVFR ceilings will move
out of the abr/aty area this morning. Otherwise...VFR conditions
are expected at all locations through today and tonight. West to
northwest winds are expected to become breezy/windy at 15 to 20
knots with gusts to 25 to 30 knots at pir and mbg as the mixing
layer deepens this morning.