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Area forecast discussion 
National Weather Service Sioux Falls South Dakota
1049 PM CST Thursday Feb 26 2015

Short term...(this evening through friday)
issued at 335 PM CST Thursday Feb 26 2015

Stratocu has developed with afternoon mixing...resulting in at least
partly cloudy skies across the area. Just enough low level
instability to even get scattered flurries...mainly across northwest
Iowa and southwest Minnesota. Expect clouds and flurries to begin
dissipating towards way to a clear night. High
pressure will move overhead as well...resulting in light winds and
thus pretty ideal radiational cooling conditions. Got colder than
forecast last winds slacked off enough to allow for some
decoupling. Tricky low forecast lighter winds will
allow for a bit better radiating...but slightly warmer temperatures
aloft will offset that to a degree. Thus went colder than consensus
by several degrees...but not quite as low as the coldest guidance.
This results in readings mainly between -10 and -15 in our snow
covered areas...and -5 to -10 towards the Missouri River where snow
cover is less. Probably will see a few of the normally colder spots
in southwest Minnesota and northwest Iowa drop even a bit lower than
-15. Given the light winds will hold off on a Wind Chill
Advisory...although any light breeze at all will push readings to
around -25.

Another well below normal temperature day on Friday. The snow cover
and southerly flow on the backside of the high do not support good
mixing. Thus thinking we only see low to middle teens in our east. Our
western areas will see slightly better warming aloft...and have less
or no snow thinking low to middle 20s from Yankton to
Mitchell and points west. Signal for stratocu seems less kept skies sunny...although an not rule out a few
afternoon clouds.

Long term...(friday night through thursday)
issued at 335 PM CST Thursday Feb 26 2015

Friday night into Saturday morning will see high pressure shift east
with return flow trying to set up. Somewhat of an inversion could
play a role in just how much the southerly winds can stir things up
so for now will not go too crazy with the non diurnal temperatures.
Lows should be near zero in the east and near 10 above in central
South Dakota.

A weak inverted trough and weak wave pass through the area on mainly
on Saturday afternoon and evening with a slightly better threat for
light snow over the eastern part of the County Warning Area. Will keep probability of precipitation low as
system not overly organized but will not be surprised to see a
little light snow...especially in northwest Iowa.

The threat for snow will slip south of the area on Saturday night
leaving a marginally chilly air mass in place on Sunday. Northwest
winds generally 10 to 20 miles per hour with highs mainly in the 20s.

In the outer periods (monday through thursday)...still some strong
hints of a potential winter system Monday into Tuesday. Will aim the
highest probability of precipitation in for Monday night and Tuesday and especially over the
southeastern half of the County Warning Area. Will continue to keep temperatures
below normal...pretty close to normal on Monday and Tuesday...then
another surge of cold air and well below normal Wednesday and
Thursday. Could be well below normal if we end up getting a swath of
3 to 6 inches of snow. Right now confidence is marginal with this
system as hints are the main effects will be south of the County Warning Area and
there are also some decent differences in the low level thermal
field. Not even out of the question to see some mixed precipitation
in mainly northwest Iowa if something closer to the GFS verifies. So
overall a lot of open ended potential for now and difficult to lean
in any one direction.


Aviation...(for the 06z tafs through 06z Friday night)
issued at 1048 PM CST Thursday Feb 26 2015

Surface high pressure will remain across the area through the
overnight producing clear and cold conditions. Reutrn flow will
gradually increase through the day Friday into Friday night.


Fsd watches/warnings/advisories...
South Dakota...none.


Short term...chenard
long term...08

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