sd discuss
Office: FSD
FXUS63 KFSD 042338
AFDFSD
Area Forecast Discussion
National Weather Service Sioux Falls SD
538 PM CST Thu Dec 4 2025
.KEY MESSAGES...
- Light snow is likely mainly north of I-90 late tonight into
tomorrow morning, but accumulations are expected to be light.
Light freezing rain (along with some sleet) looks to mix in
when precipitation begins, with a light glaze possible along
the Highway-14 corridor in central South Dakota mainly on
elevated surfaces and untreated roads.
- Confidence is increasing in the potential for accumulating
snowfall Saturday into Saturday night. There is a medium-to-
high chance (40-70%) of at least 3 inches of snow, especially
over portions of southeast South Dakota, northwest Iowa, and
southwest Minnesota.
- Cold, below normal temperatures are expected to continue
through the weekend, with signs of temperatures moderating
closer to normal next week.
&&
.DISCUSSION...
Issued at 256 PM CST Thu Dec 4 2025
It was either a bitterly cold Thursday through and
through or a fairly decent December day depending on which side of
the stratus you ended up on. Where skies cleared early like in
central South Dakota, we've managed to make it to around 30 degrees
and even as mild as the low-40s! Where stratus lingered most of the
day like for areas east of the James River, we've only made it to
the teens for the most part. A milder night is ahead compared to
last night though, with temperatures dropping into the lower 10s
to middle 20s by sunrise Friday morning.
An active upper-level pattern will send a couple of waves through
the area this weekend. The first wave will bring a chance of mainly
light snow with some mixed precipitation, starting along the Highway-
14 corridor in central South Dakota and spreading eastward through
the morning, but mostly staying along and north of I-90 through the
day. Soundings indicate a warm nose around 900 mb during the onset
of precipitation, and with below freezing surface temperatures, we
will likely see some freezing rain mix in whenever precipitation
starts, along with some sleet as well. Not expecting much in the way
of ice accumulations, but can't rule out a light glaze mainly on
elevated surfaces and untreated roads along the Highway-14 corridor
in South Dakota. As the warm layer diminishes with time, snow
will become the dominant precipitation type, though snow is
expected to remain light. We'll see a dusting to a tenth or two
of an inch of snow, highest amounts over the Highway-14 corridor
in southwest Minnesota. Highs on Friday look to be in the 30s
across the area.
A stronger system will take shape on Saturday as another upper-level
wave moves in from the northern Rockies into the central Plains,
with a surface low developing over Wyoming in response. That surface
low looks to dive southeastward into central Nebraska, putting
us on the snowy side of the system. A band of snow looks to
develop in response to WAA at 850 mb, starting in central South
Dakota Saturday morning and spreading east-southeastward
throughout the day. Snow looks to exit off to our southeast into
central Iowa by the late evening. Snowfall rates could be
moderate to locally heavy at times, and this will likely lead
to a few inches of snow across much of the area, especially from
southeastern South Dakota into northwest Iowa and southwest
Minnesota. In those areas the NBM probabilities of at least 3
inches of snow ranges from 40-70%, while the probability of at
least 6 inches is around 10-30%. Winds don't look to be too
strong with this system, but another messy travel day is growing
increasingly likely for Saturday, so keep up to date with the
latest forecast!
Colder air will move in after Saturday's system, with lows dropping
to the single digits on either side of zero by Sunday morning.
Sunday will be cold with highs in the single digits to teens and
lows Sunday night once again in the single digits on either side of
zero. Our next best chance of precipitation looks to be around the
Tuesday-Wednesday time frame, though it is too far out to determine
specifics. At this point, temperatures look to be a little warmer
(or at least, closer to normal) by then, so the system may
bring us rain to start with a changeover to snow on the backside
of the system.
&&
.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 538 PM CST Thu Dec 4 2025
Latest satellite imagery shows two areas of stratus. One is along
and east of I-29 with ceilings down to MVFR/IFR levels and the other
is just beginning to push into the area from the northwest as it
sitting at VFR thresholds. The MVFR/IFR stratus will continue to
push eastwards through the evening hours while winds turn
southwesterly. Some low level wind shear (LLWS) is expected at KSUX
for a few hours this evening as well. A warm front will push through
the area tonight, turning winds to out of the west in its wake. This
front will also bring mixed precipitation chances tonight through
tomorrow morning for locations along and north of highway-18. Mainly
dry conditions and weakening northwest winds will finish out the
afternoon hours tomorrow.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&
$$
DISCUSSION...Samet
AVIATION...Meyers
Office: UNR
FXUS63 KUNR 042234
AFDUNR
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
334 PM MST Thu Dec 4 2025
.KEY MESSAGES...
- Light snow returns tonight into Friday, with another chance on
Saturday into Sunday.
- Warmer and breezy conditions early next week.
&&
.DISCUSSION...(This Evening Through Thursday)
Issued at 127 PM MST Thu Dec 4 2025
An upper air analysis shows northwest flow continues over the
northern plains today, with a weak disturbance over eastern MT.
Surface chart depicts low pressure over western SD, with warm
frontal boundary now through the forecast area, towards central
SD. Temperatures currently sit in the mid 30s to low 40s, with
light to breezy westerly winds.
Clouds will increase this evening ahead of the next wave as it
drops down from eastern MT. Light precipitation arrives tonight,
late enough that it should remain as snow. Expect little to no
accumulations with this wave, however upslope over the northern
Black Hills will bring minor accumulations of 1-3 inches. Light
precipitation will taper off Friday morning, with dry conditions
expected the latter half of the day, and similar temperatures to
today. Another disturbance moves in late Friday and associated
cold front will drop down from MT/SD. Expect a slight decrease in
temperatures for Saturday, and another chance for light
precipitation during the day into Sunday morning. Some areas in
the western SD plains could see 1-2 inches, with the higher
elevation Black Hills perhaps seeing slightly higher amounts.
Unsettled pattern will bring more chances for light precipitation
early next week, however low-level warmer air moving in will bring
mild (but breezy) days for Monday and Tuesday, with highs for some
areas climbing into the 50s.
&&
.AVIATION...(For the 00Z TAFS Through 00Z Friday Evening)
Issued At 332 PM MST Thu Dec 4 2025
An incoming system will bring light snow to northern and western
portions of the area around 03Z tonight. Increasing MVFR/IFR
conditions are expected, especially across northeast Wyoming, the
Black Hills, and through northwest South Dakota overnight into
Friday morning.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&
$$
DISCUSSION/KEY MESSAGES...Dye
AVIATION...Wong
Office: ABR
FXUS63 KABR 042353
AFDABR
Area Forecast Discussion
National Weather Service Aberdeen SD
553 PM CST Thu Dec 4 2025
.KEY MESSAGES...
- Downslope winds expected from Sisseton south to Brandt this
afternoon, with gusts from 40-50 mph. This will create areas of
blowing/drifting snow with localized areas of reduced visibilities
down to a mile at times.
- System late tonight into Friday bringing generally around an inch
or less of light snow. Areas in south central SD could see freezing
rain to a wintry mix of precipitation tonight, which could cause a
light glaze on surfaces Friday morning.
- Snow chances (50-70%) return Saturday as a clipper system moves
through, producing a dusting of snow to the north and an inch or two
of snow south of US-212. There will be periodic lower chances for
snow (20-40%) through early next week, as more weak weather systems
have the potential to move through the region.
&&
.SHORT TERM /THIS EVENING THROUGH FRIDAY NIGHT/...
Issued at 212 PM CST Thu Dec 4 2025
As of 20z, strong downsloping winds are gusting along the eastern
side of the Prairie Coteau. This is leading to wind gust
observations of 40-50 mph in areas, as well as drifting and patchy
blowing snow locally reducing visibilities down to a mile or less at
times. These strong winds will continue to stay strong into the
evening before weakening again.
Tonight, a small clipper will move into central and northeastern SD
from ND. This clipper will mostly bring light snow flurries for
north central SD tonight and for northeastern SD late tonight
through Friday morning. There is a bit of warmer air aloft, and this
should cool below freezing for most areas before precipitation
starts to fall. However, south central SD could stay warmer aloft
for longer causing the snow to melt as it falls before it reaches
the surface. Since surface temperatures will be around/below
freezing, this melted snow could freeze as it reaches the ground
leading to freezing rain or a wintry mix of precipitation. It is
possible for a light glaze of ice to form in a line from the Pierre
and Redfield areas and to the south. Snowfall amounts look to be an
inch or less, higher amounts in northeastern SD.
Temperatures will continue be warmer than previous days with
tomorrow forecast to have highs in the upper 20s to mid 30s. At the
same time, wind chills will stay above 0, with most areas getting
into the teens to lower 20s tonight and tomorrow.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
Issued at 212 PM CST Thu Dec 4 2025
General theme for the long term part of the forecast is
northwesterly flow aloft leading to clipper systems moving through
the region every 18-24hrs. This will bring periods of light snow
with the clippers and variable temperatures (warming in front of and
colder behind). All in all, the lighter snow should only lead to
minor impacts as accumulations will generally be a light dusting to
an inch or two at the most (primarily on Fri night into Saturday in
central SD).
The greatest uncertainty with these clipper systems comes with the
amounts and location of the greatest snowfall for the Friday night
into Saturday system. The uncertainty has been there for the last
several days, largely with the track of the surface low and the
intensity of the Canadian high to the north. It does seem like we're
seeing more consistency now with the low tracking from central MT on
Friday night to central NE by Saturday afternoon. This will lead to
snow occurring on the north-northeast side of the low and tied to
the 850-700mb warm air advection and FGen forcing. The swath of snow
is expected to stretch southeast across central SD and into
southeast SD, but the exact track is still a little uncertain. The
latest in the ensemble snowfall amounts highlight a dusting (10-25th
percentile) to over 3" (90-95th percentile) for the
Mobridge/Pierre/Faulkton area and then lesser amounts as you head
farther to the northeast. The trend does continue to point towards
the greatest amounts being to the south of our forecast area on
Saturday, as the forcing intensifies in southeast SD. Will need to
continue to fine-tune this forecast over the next day.
Behind that clipper, high pressure builds in for Saturday night into
Sunday morning before the next clipper, but this looks to be drier
and struggles as it runs into the high over central SD. The next
potential clipper for Sunday night into Monday looks to be farther
north (more of a eastern ND and northern MN snow), before the next
one on Tues night into Wed (this one is a little farther south and
does bring some snow potential to northeast SD and rain/snow to
central SD). As mentioned above, these clippers appear to be lighter
on snow than Saturday and only expect a light dusting. Fortunately,
with the snow on the ground, no significant winds expected at this
time (limiting blowing snow), although probabilities of 34kt or
greater do increase to above 50% for Tues/Wed next week with that
clipper.
&&
.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 553 PM CST Thu Dec 4 2025
Terminals KABR,KATY,KPIR,KMBG
VFR conditions start the period, as ATY just went to SCT instead
of BKN008. These lower clouds may only temporarily return through
02Z. A surface trough pushing through the Dakotas will bring
light precipitation with it. 3-5 hours of light snow will be
possible at most locations overnight into Friday morning with IFR
to LIFR ceilings. Given the slightly warmer conditions and the
cold ground at PIR, 3 hours of -FZRA is possible. Confidence is
lower at PIR, so the -FZRA has only been included at a TEMPO basis
for now. IFR to LIFR ceilings look to stick around longest at
ATY, from 11Z Friday until 00Z Saturday.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
SHORT TERM...Vipond
LONG TERM...SRF
AVIATION...06
