339
FXUS63 KFSD 061957
AFDFSD

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

.KEY MESSAGES...

- Quick hitting snowstorm continues to move east through the
  Tri-State area, producing average snowfall of 2 to 7" by time
  it ends. Travel will be difficult this afternoon, with slow
  improvement this evening.

- 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 /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1121 AM CST Sat Dec 6 2025

Moderate to heavy snow continues to move east of I-29 at mid-
day. Expecting more linear band of snow to begin to pivot and
lift north and east this afternoon, focusing in areas from Huron
to Sioux Falls and Spencer. LIFR or lower visibility expected
with ceilings dropping as low as 500 ft at times. Occasional 20
knot gusts may be possible, which could lead to brief blowing
snow by late afternoon and early evening.

Snow will slide southeast this evening, leaving MVFR ceilings. A
secondary area of light snow may drift southward out of North
Dakota into central and east central South Dakota overnight.
Visibilities may be slightly impacted in areas along Highway 14
into Sunday morning, with flurries elsewhere.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...Winter Weather Advisory until 9 PM CST this evening for SDZ040-
     055-056-069>071.
     Winter Weather Advisory until 6 PM CST this evening for SDZ038-
     039-053-054-059-060-065-068.
     Winter Storm Warning until 9 PM CST this evening for SDZ061-
     062-066-067.
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 NEZ013-
     014.

&&

$$

DISCUSSION...Dux
AVIATION...Dux