sd discuss
Office: FSD
FXUS63 KFSD 040445
AFDFSD
Area Forecast Discussion
National Weather Service Sioux Falls SD
1045 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 /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1045 PM CST Wed Dec 3 2025
Current satellite imagery continues to show MVFR stratus sitting
along and west of the James River. Low level flow is turning
southerly/westerly, keeping the stratus from sinking south. With
southwest/west low level flow in place, the stratus has began a
crawl to the east. As such, have included MVFR ceilings for KHON for
the entire night. Will monitor the stratus's trends through the
night in case to see if any amendments will be needed. But
currently thinking has the stratus breaking up around daybreak. At
the surface, high pressure is passing through the area, turning
northwest winds ahead of it to out of the south in its wake. These
southerly winds will persist through the morning hours and even turn
a bit more to out of the southwest by the afternoon hours. Winds
will strengthen much more for the afternoon time frame as well with
gusts up to 20-35 knots expected. The strongest winds will reside
along the Buffalo Ridge in southwest Minnesota. Winds will slowly
wane through the rest of the period but some low level wind shear
(LLWS) is expected for the end of the period at KSUX.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&
$$
DISCUSSION...Samet
AVIATION...Meyers
Office: UNR
FXUS63 KUNR 040508
AFDUNR
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1008 PM MST Wed Dec 3 2025
.KEY MESSAGES...
- Light snow/flurries ending across the region.
- Gradual warming trend to end the week.
- Unsettled weather will continue into next week.
&&
.DISCUSSION...(This Evening Through Wednesday)
Issued at 1232 PM MST Wed Dec 3 2025
Light snow and flurries will come to end across the area as we
continue to progress into the late afternoon hours. Extensive
cloud cover will keep temperatures cold with very limited warming
occurring across the region today. A surface high pressure over
eastern South Dakota will allow for some clearing over the eastern
plains this evening and with the light winds forecast, overnight
lows will easily drop into the single digits. With this persistent
NW flow aloft expected to remain in place we can't rule out
pockets of light snow developing across the Black Hills,
especially tomorrow afternoon when another fast moving shortwave
is progged to move through the area. This will help initiate those
areas of snow over the Black Hills. Adjacent valley locations may
see low end snow chances tomorrow afternoon and into the evening
with as this shortwave moves through. Minimal accumulations are
expected across both areas.
Heading into Friday and into the weekend, we will remain in the NW
flow aloft, but some marginal warmer air will have worked its way
into the northern Plains so temperatures are progged to slowly
modify on Friday but this will only get temperatures into the 40s
across the plains. As we progress into Friday night, another
shortwave will move through and bring light snow into the
forecast. The best chances for accumulating snow will be again,
across the Black Hills that will fall between Friday and Saturday
night. The long range forecast continues to show chances for
precipitation as shortwaves continue to move through.
&&
.AVIATION...(For the 06Z TAFS Through 06Z Thursday Night)
Issued At 1006 PM MST Wed Dec 3 2025
MVFR/IFR conditions in low clouds will slowly erode overnight as
drier air filters into the region tonight with VFR conditions
expected area-wide after 08-10z.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&
$$
DISCUSSION/KEY MESSAGES...Woodward
AVIATION...SE
Office: ABR
FXUS63 KABR 040513
AFDABR
Area Forecast Discussion
National Weather Service Aberdeen SD
1113 PM CST Wed Dec 3 2025
.KEY MESSAGES...
- Patchy fog possible over portions of northeastern SD late this
evening into the early morning hours Thursday.
- Cold temperatures expected tonight with lows in the single
digits below and teens below zero. Wind chill values will range
in the teens and twenties below zero east of the Missouri River.
- Downslope winds expected in the Sisseton Hills region on
Thursday, with gusts potentially over 40 mph. This may create
areas of blowing/drifting snow.
- Snow chances (20-40%) return Friday and Saturday through early
next week as more weather systems have the potential to move
through the region.
&&
.UPDATE...
Issued at 539 PM CST Wed Dec 3 2025
Patchy fog has been added to portions of northeastern SD late this
evening into the early morning hours Tuesday, before winds
increase out of the south near/just prior to 12Z. Otherwise, the
ongoing forecast remains unchanged at this time.
&&
.DISCUSSION...
Issued at 216 PM CST Wed Dec 3 2025
As of 2pm, satellite indicates clear skies James Valley and eastward
with stratus clouds continuing over central South Dakota and
upstream through western ND. Current temperatures range in the
single digits to the mid teens, warmest over south central SD. A
1035mb arctic high will be directly overhead by this evening,
tracking southeast through the overnight with the center of the high
over IA by 12Z Thursday. Winds will diminish west to east across the
CWA through this evening becoming light through about 06Z. Models
indicate the coldest temperatures will be around the 06Z timeframe
before winds shift out of the south/southwest and WAA moves in as
the CWA will be on the downstream side of a surface trough that will
be positioned south of a low in Canada. HREF grand ensemble 925mb
temps look to range between -9 to -17C at 06Z, coldest James Valley
and eastward and 850mb temps of -10 to -15C. Kept the trend of
dropping the surface temps below mean NBM guidance, closer to the
25th percentile. Forecast lows range from the single digits above
zero to around 11 degrees west of the Mo River to the single digits
to the teens below zero east of here, coldest over the James Valley.
Minimum wind chill values east of the Mo River are forecast to range
in the teens to twenties below zero. With the WAA after midnight, we
will see temps rise from west to east across the CWA, with temps by
12Z Thursday ranging from the single digits below zero to the lower
teens, highest over south central SD. As the surface trough/warm
front track east across the CWA through the day Thursday, highs will
be warmer ranging in the 20s and 30s!
Our next concern will be the gusty winds over and downslope of the
Coteau for Thursday as we see an area of higher winds on the
downstream side of this 925/sfc trough over the eastern Dakotas into
western MN. HREF 925mb winds indicate speeds between 30-40mph out of
the southwest at the top of the inversion layer. HREF is showing
surface gusts of 30-45mph with NBM max gusts around the same.
Comparing NBM/NBM5.0 is pretty close, about 5kts higher in any one
location. The highest winds at 925mb, therefore, the highest gusts
at the surface will be in the morning through the late afternoon
with winds diminishing towards the evening. EC EFI does highlight
this potential well with pockets of 0.6 to 0.7 with EFI of zero for
the downsloping wind gusts. Drifting to patchy blowing snow is
expected, luckily with the warming temps expected and snow age this
should prevent any lofting/widespread blowing snow.
Through at at least early next week we continue in a persistent
northwest flow pattern with a near stationary mid level low over the
Hudson Bay and a ridge to our west. Models indicate several embedded
shortwaves/lows tracking southeast and over the Northern Plains
through the extended. With the low mentioned above tracking across
Canada Thursday/Friday and its shortwave, HRRR along with ENS/GEFS
indicate the chance of flurries/light snow ahead of a cold front
late Thursday night through Friday within this surface trough. NBM
did not show anything so with collab from the offices, we increased
pops and used WPC for QPF to show for this. Pops range from 15-30%
Friday with a couple tenths of snow accumulation possible over north
central through northeastern SD. Our more notable wave/Clipper low
looks to possibly affect the region Saturday, however low confidence
exists due to model disagreement at this time on track and intensity
of low and where the "highest snowfall" may occur. GEPS has a track
more over central SD and ENS more across the northern CWA. NBM
probability of 24hr snow ending 12Z Sunday>0.10" is 45-70% with 25%
or less for an inch of snow. The good news for now is that we are
not expecting heavy snow for any one period during the extended.
&&
.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1113 PM CST Wed Dec 3 2025
Terminals KABR,KATY,KPIR,KMBG
It's a difficult TAF forecast starting out, as limited model
guidance shows the MVFR cloud deck over central SD, or if they do
the coverage is not as extensive as it has been. It will likely be
a battle between fog or the MVFR deck nearing from the west at
ABR. At the current time the clouds are forecast to move over ABR
around 08Z, with the lower visibilities down to around 2SM staying
in a TEMPO group due to the lower probability of occurrence.
Farther east at ATY the clouds at their current pace would get
there around 13Z. If fog develops, increasing winds out of the
south may limit fog to prior to 11Z at both ABR and ATY.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...06
DISCUSSION...MMM
AVIATION...06
