821
FXUS63 KFSD 070000
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
600 PM CST Sat Dec 6 2025

.KEY MESSAGES...

- Snow has ended or become light flurries for most areas to the
  west of I-29. Light snow continues to the east through this
  evening before becoming flurries through about midnight.
  Though snow is ending, accumulations on roadways may still
  impact travel through Sunday morning.

- Wind chills fall as low as -20 by Sunday morning, coldest
  over Southwest Minnesota.

- A parade of waves will move through the region during the
  week ahead, bringing snow risks Sunday afternoon, Tuesday, and
  again Thursday. The most impactful snow system to watch may
  be Thursday.

- Confidence is growing that winds Tuesday night into Wednesday
  may break or exceed the 40 mph mark. We`ll need to monitor
  the snow pack and air temps closely to monitor blowing snow
  potential.

&&

.DISCUSSION...
Issued at 152 PM CST Sat Dec 6 2025

THIS AFTERNOON: A corridor of moderate to heavy snow continues to
develop and pivot over the Tri-State area early this afternoon.
We have yet to see any instability release in the form of
lightning, but short term guidance is still hinting at very low
probabilities near Highway 20 over the upcoming 1-2 hours. Snow
rates have increased considerably since noon, with 1" per hour
totals now expected through 4-5pm, along a line from Sioux Falls
to Spencer and Storm Lake. Snow forecast totals remain in line,
with an average of 4 to 7" likely by time snow dissipates early
this evening.

TONIGHT: Light snow to flurries may linger behind the departing wave
through 9-10pm this evening, but accumulation will be minimal.
Further northwest, WV imagery showing a secondary impulse drifting
southeast.  A bit of light snow may accompany this wave into
southeastern South Dakota overnight, likely dissipating to flurries
by daybreak.  Clouds may hold on in most areas outside of SW
Minnesota tonight, which will hold temperatures upwards.  Wind
chills however in central to southwest Minnesota may fall as low as
-20F. No advisories are planned at this time.

SUNDAY: Good model agreement in the next shortwave moving through
the Plains Sunday afternoon and evening.  While lift is not nearly
as strong as the system moving through Saturday, a narrow corridor
of warm advection light snow will pass from west to east in the
afternoon and evening.  Amounts will stay less than 1" in most
areas.  Temperatures will be quite a bit colder on Sunday, with
highs only in the single digits to teens. Winds though remain light,
preventing any significant blowing snow.

MONDAY-TUESDAY:  A parade of waves can be expected during the
upcoming week, with a piece of mid-lvl vorticity tracking through
the Plains nearly every day.  Behind Sunday`s shortwave, a brief
period of warming may take place overnight into Monday as mid-lvl
heights rise. Temperatures may rise into the upper 20s to
30s, but some questions remain on the impacts of fresh snow cover.
Shortwave energy moving along the Canadian border Monday night will
set the stage for a warmer Tuesday as westerly downslope flow
develops ahead of yet another wave poised to deepen in the upper
Midwest Tuesday.  Temperatures Tuesday rise into the middle 30s to
40s in many areas, pushed upwards by breezy westerly to
southwesterly surface winds.

TUESDAY NIGHT-FRIDAY:  The deepening clipper moving into northern
Minnesota Tuesday night will need to be monitored closely. At
this time, most guidance keeps the wave (and associated
moderate snow) well northwest of the CWA. However, this track is
favorable for one thing...the rapid rush of strong
northwesterly winds around the deepening trough Tuesday night
into Wednesday. The first frontal passage during the night will
first bring a burst of 30 to 40 mph winds, and then second
boundary will bring crashing temperatures and another surge of
40+ winds. All three ensembles are bullish on this concept with
70%+ probabilities of at least 40 mph winds. We`ll have to
monitor the snow pack condition and temperatures closely
Tuesday. 24 hours of temperatures above freezing should compact
the snow and make it less likely to blow around. This seems
supported by the various blowing snow tools, which would suggest
the blowing snow risk could develop only early Wednesday with
crashing temperatures. Have manually boosted winds over the NBM.

A great deal of uncertainty builds for the end of next week, as yet
another wave will track southeast into the Plains by Thursday.  The
depth and track of the next wave remains in doubt, with some models
suggesting rapid deepening over the Dakotas, with others keeping the
vorticity more muted in the strong NW flow.

SATURDAY-SUNDAY:  Confidence in a drop of temperatures for next
week is rising, as upper troughing deepens over the Great Lakes.
This would allow an arctic high to filter southward into the Central
US.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 557 PM CST Sat Dec 6 2025

Snow has tapered off or has become light flurries for most of
southeastern South Dakota and northeastern Nebraska. The exception
is along the I-29 corridor and east where light snow is expected to
continue for a few more hours. This too will then taper off becoming
light flurries later this evening. Flurries may continue through
midnight.

A secondary area of light snow is expected to move from north
central into southeastern South Dakota. This is expected to be
very light with light winds, with only minor impacts to KHON.

Mostly IFR to MVFR ceilings will gradually improve through the
overnight to MVFR to VFR. However, the break will be short as
another fast moving snow shower moves in from the southwest Sunday
afternoon. This will move quickly northeast through the region,
producing light snow through the end of the period. Light northerly
winds will gradually become southeasterly through the day Sunday.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...Winter Weather Advisory until 9 PM CST this evening for SDZ040-
     056-071.
     Winter Storm Warning until 9 PM CST this evening for SDZ062-
     067.
MN...Winter Storm Warning until midnight CST tonight for MNZ089-090-
     098.
     Winter Weather Advisory until midnight CST tonight for MNZ071-
     072-080-081-097.
IA...Winter Storm Warning until midnight CST tonight for IAZ001>003-
     012>014-021-022.
     Winter Weather Advisory until midnight CST tonight for IAZ020-
     031-032.
NE...Winter Weather Advisory until 9 PM CST this evening for NEZ014.

&&

$$

DISCUSSION...Dux
AVIATION...AJP