Scientific Forecaster Discussion
Area forecast discussion...updated
National Weather Service Aberdeen South Dakota
959 am CST Thursday Jan 29 2015
current forecast is in fine shape. Added in a little bit of patchy
freezing drizzle/occl flurries mention to the east to cover
anything that spills over from fgf's forecast area /upstream observation
and radar indicating flurries are working southward toward the
cwa/. Kept the clearing trend going out west...but opted to hold
onto clouds across the eastern County Warning Area basically to the end of the
today period...before dissipating them. Will let the current
forecast high temperatures play out and see how much of a Dent
late January sun with no snow on the ground can warm things up
with clouds in place and low level cold air advection ongoing.
See below for an updated aviation forecast discussion.
short term...today through Saturday
the main forecast challenge today will be how long the stratus
deck sticks around. There is a pretty defined edge to stratus and
it does appear to be very slowly moving eastward. So did take an
optimistic approach...and started to clear clouds out later this
afternoon and evening. Gusty northwest winds are expected to
gradually decrease through the day as high pressure slides over
the region. Cold air advection will keep temperatures relatively
cooler...but will still be above normal for this time of the year.
Tonight...the surface ridge pushes east and a return flow/warm
air advection pattern again sets up across the west. Winds will go
light across the eastern County Warning Area and temperatures will drop into the
teens...however temperatures will remain in the 20s where the
southwesterly flow sets up across the western County Warning Area. A trough will
move across the region Friday...but not before temperatures rise
into the 40s and 50s Friday afternoon. The trough will pass
dry...but another shot of cold air advection and gusty northerly
winds will follow Friday night.
Yet another shortwave will approach the region Saturday. This
system may bring a shot of light snow to the region...however best
chances look to be later in the day or Saturday night.
Long term...Saturday night through Wednesday
northwest flow aloft will be dominant throughout the extended
period...with a couple of shortwaves tracking across the northern
plains. The first will move through late Saturday night and
Sunday...with the second tracking through Monday night into early
Tuesday. A couple of surface clipper systems will be associated
with the upper level shortwaves...bringing chances of light snow
with them. High pressure will dominate in between the clipper
Sunday will be the coolest day of the period as fairly strong high
pressure drops in behind the first clipper system...with highs
likely only in the single digits and teens. Will then see
temperatures back around normal for the remainder of the
period...generally in the upper teens to lower 30s for highs.
12z tafs for the kabr...Katy...kpir and kmbg terminals
MVFR ceilings will remain over the area through much of the day. These
ceilings will move out late this afternoon or early this
evening...then VFR conditions will prevail through the end of the
taf period. Northwest winds of 15 to 30 knots currently occurring
will begin to diminish during the middle to late afternoon hours.