909
FXUS63 KFSD 032340
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
540 PM CST Wed Dec 3 2025

.KEY MESSAGES...

- A very cold night is ahead with wind chills falling to the -15
  to -25 degree range especially along and east of the James
  River.

-  Wind gusts nearing 40 mph tomorrow afternoon over southwest Minnesota
   and nearby parts of eastern South Dakota and northwest Iowa
   will lead to patchy blowing snow in those areas. Please use
   extra caution on the roads.

- An active pattern will bring a couple of waves of light snow
  this weekend. The first one on Friday will bring light amounts
  mainly north of I-90, with a dusting to a couple tenths of an
  inch of snow possible. Amounts with the second system on
  Saturday are a bit more uncertain due to questions regarding
  the track of the system, so keep up to date with the latest
  forecast.

- Cold, below normal temperatures are expected to continue
  through the weekend, with signs of temperatures moderating
  closer to normal next week.

&&

.DISCUSSION...
Issued at 250 PM CST Wed Dec 3 2025

It`s a cold December day out there with temperatures
ranging from the single digits to the teens and wind chills below
zero this afternoon. Heading into tonight, we`ll see mostly clear
skies as a high pressure system moves across the area from northwest
to southeast. This will cause winds to decrease overnight, but
temperatures will drop quickly due to the clear skies. We`re looking
to see lows drop between 0 and -15 degrees along and east of
the James River, coldest over parts of northwest Iowa and
southwest Minnesota. So even with the light winds we are
expecting into those locations, we will see the wind chills
drop to the -15 to -25 range by daybreak Thursday. These wind
chills reach marginal Cold Weather Advisory levels, but due to
the only occasional drops to -25 or below degree wind chills
expected over a period lasting 2-4 hours, along with the fact
winds will be light overall, opted to forgo cold weather
headlines at this time. It will be a little "warmer" west of the
James River tonight due to increasing warm air advection at 850
mb, but winds will also be increasing in these areas through
early tomorrow morning as high pressure moves off to the east,
leading to wind chills still as low as around -10 degrees.

Winds will pick up area-wide through the day tomorrow as a surface
low deepens over southern Canada. Wind gusts up to and just over 40
mph appear possible to be mixed down especially over the higher
elevations of the Buffalo Ridge tomorrow afternoon and evening, with
HREF probabilities showing a 20-50% of wind gusts exceeding 45 mph
in these areas. At this point, the potential for patchy blowing snow
looks to be the main concern with these winds, especially over
southwest Minnesota into adjacent parts of northwest Iowa and
eastern South Dakota. Highs on Thursday will be mainly in the
teens and 20s, though parts of south-central South Dakota will
see highs into the 30s.

We look to be stuck in a northwest flow pattern aloft through the
weekend, and this will mean a series of waves will move through the
area. The first one looks to move through on Friday, with the GFS
and NAM having snow mainly north of I-90, while the EC and Canadian
have snow a bit farther south. Looking at ensembles, mean 24-hour
QPF looks to be only a couple hundredths on Friday, with the EC
ensemble showing the highest amounts, up to about six hundredths
for the Highway-14 corridor in southwest Minnesota. This is an
outlier, so at this point, look for light accumulations up to a
dusting to a tenth or two of an inch of snow for mainly north of
I-90 with this system. Temperature-wise on Friday, look for a
milder day despite the snow chances, with highs in the 20s and
low-30s where snow falls, and mid-to-upper-30s where we are dry.

Another wave is set to move through on Saturday, but there is
still little agreement as to how snow will unfold amongst the
guidance. The NAM keeps all the snow south of the area, while
the GFS has it just clipping the Missouri River Valley in
southern South Dakota. The EC and Canadian are both further
north and thus more impactful to our area. Looking at the
ensembles, the EC has the highest mean QPF out of the rest,
with up to three tenths of an inch on Saturday into Saturday
night mainly over northwest Iowa. The GEFS/GEPS/LREF generally
show a broad 0.05 to 0.15" mean QPF, with the higher amounts
favored for areas along and south of I-90. The NBM jives with
these lower amounts, but is similar to the EC in that it shows
the highest QPF over northwest Iowa (still only up to around a
tenth verses the three tenths shown by the EC Ensemble). Bottom
line is that uncertainty remains and it will all depend on the
track of the system. If the NAM and GFS track comes true, then
it would be less snow for us. If the EC and Canadian track comes
true, then it would favor higher snowfall totals. Keep up to
date with the latest forecast! Temperatures are set to turn
colder once again on Saturday with highs back down into the
teens and 20s and lows Saturday night dropping below zero
degrees for many of us.

After another unseasonably cold Sunday and Sunday night, look for
temperatures to begin to moderate once again heading into the next
work week. Another storm system is set to move through the area on
Tuesday or Wednesday depending on the model (though most favor a
late Tuesday into Wednesday time frame). There are signals that we
could be within the warm sector of this system at least at the
start, which would favor liquid precipitation and then a changeover
to frozen precipitation as cold air moves in on the backside of the
system. This is still several days out, so uncertainty is high at
this point in time with this system.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 539 PM CST Wed Dec 3 2025

Latest satellite imagery shows MVFR stratus generally west of the
James River sinking southwards this evening. Could see the stratus
wobble westwards so will keep an eve on trends through the evening.
A small portion of the stratus resides just west of KSUX. Given its
southerly motion, expected the stratus to stay west of the terminal.
The stratus will continue to sink southwards through the rest of the
evening and overnight hours.

Winds will turn to out of the south come tomorrow morning and
strengthen into the afternoon hours. Gusts up to 20-35 knots is
expected with the strongest gusts occurring along the Buffalo Ridge
in southwest Minnesota. Winds will be on a weakening trend to end
the TAF period.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.

&&

$$

DISCUSSION...Samet
AVIATION...Meyers