sd discuss
Office: FSD
FXUS63 KFSD 010446
AFDFSD
Area Forecast Discussion
National Weather Service Sioux Falls SD
1046 PM CST Sun Nov 30 2025
.KEY MESSAGES...
- Wintry cold continues through the upcoming week. Morning low
temperatures will fall into the single digits with nighttime
wind chills below zero.
- Scattered light snow may bring minor travel impacts near and
south of the I-90 corridor Monday morning through early
afternoon. High confidence that most locations will see under
a half inch of new snow.
- Low chances for light snow develop again Tuesday night into
Wednesday with a passing cold front. Behind the front, wind
chills of -10 to -25F look increasingly likely for Wednesday
night into early Thursday.
&&
.DISCUSSION...
Issued at 243 PM CST Sun Nov 30 2025
TONIGHT AND MONDAY: 20z satellite images show dry air filtering
in from the north has eroded much of the morning's stratus east
of I- 29, but stubborn stratus continues to produce flurries
across much of southeast SD and northeast NE this afternoon.
Models have underestimated lingering stratus and flurries today
but favor a quickly saturated near-surface layer after sunset.
Given high confidence in this, have added patchy fog across much
of the region tonight. Could certainly see areas of or
widespread fog, but confidence was too low to add given poor
model performance. Temperatures should bottom out in the single
digits above zero Monday morning.
Besides potential for fog, the main focus tonight is on increasing
chances for light snow with a progressive mid level wave and
associated upper trough axis. Despite hesitancy from the NBM and
given today's dry bias from models, opted to increase snow chances
and QPF toward WPC/HRRR/RAP for late tonight into Monday afternoon
near and south of the I-90 corridor. 12z HREF guidance continues to
suggest potential for light snow accumulations in this area,
generally under a half inch and highest near the Hwy 20 corridor.
Expect this to only bring minor impacts to already wintry road
conditions. Furthermore, cloudy skies, a south breeze and highs in
the 20s on Monday will make for a chilly start to the week.
MONDAY NIGHT AND TUESDAY: Temperatures drop near to below zero
Monday night as the upper trough passes. Broad 925-850mb warm air
advection develops across the central U.S., ahead of a rapidly
approaching northern stream clipper. Model forecast soundings
suggest higher potential for fog Monday night into early Tuesday
with a stout nocturnal inversion developed atop a saturated sfc
layer.
Tuesday should be notably warmer than Monday if nighttime fog and/or
stratus can mix out. Highs are expected to moderate back into the
20s, and even 30s west of the James River where the snowpack is
lesser.
MID WEEK: Tuesday night into Wednesday sees the passage of a stout
cold front, plunging us back into even colder air. Light snow or
flurries are looking increasingly likely to accompany the front
early Wednesday, along with gusty northwest winds. Depending on the
timing the front moves through, this could bring some minor
impacts to the Wednesday morning commute.
Confidence is increasing that a strong Arctic high pressure system
will bring a major temperature drop Wednesday night if skies can
clear. Temperatures may reach the single digits to teens below zero,
with a wind chill nearing -10 to -25F. Thursday morning has
certainly become a period to watch for unusually cold temperatures.
LATE WEEK: For Thursday and Friday, strong upper ridging in the
Pacific begins to break down, planting the Central U.S. into a more
active zonal flow regime for late week and next weekend. Low
confidence in the track of any significant weather systems impacting
the region but temperatures remain favored to be more wintry/below
normal.
&&
.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1045 PM CST Sun Nov 30 2025
An uncertain short-term forecast is currently ongoing across the
area. MVFR stratus has parked itself generally along and west of I-
29 and is stationary. This is because of a low level surface ridge
that is beginning to slide off to the east. As this ridge pushes
eastwards, low level winds will turn to out of the south/southwest.
This could result in the stratus pushing off to the north/northeast
and advecting drier air into the area. However, the uncertainty
comes with the next potential for light snow. This incoming wave
could saturate low level thermal profiles and result in additional
stratus formation, keeping low level stratus locked in place. Have
gone with the locked in place option as of now but trends will be
closely monitored through the night.
Latest guidance still continue to show the potential for fog to
develop. However, no fog is present across the area. Think that any
fog potential will come east of I-29 where skies are mainly clear.
Have taken out any mention of mist (BR) in KFSD and KSUX's TAFs
since the MVFR stratus continues to sit over all TAF terminals.
Chances for light snow will arrive a bit before daybreak, generally
along highway-20. That said, latest guidance has backed off a bit on
the snow. Still could see some light snow so have kept a PROB30
group in KSUX's TAF. Still think that ceilings and visibilities will
remain at MVFR levels in the snow.
Given the uncertainty in the stratus's progression, have kept MVFR
stratus in all TAFs through the night. Think the stratus will begin
to lift tomorrow morning but again, will need to keep a close eye on
its trends. Southerly winds will pick up by tomorrow afternoon
before going light and variable to end the TAF period.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&
$$
DISCUSSION...BP
AVIATION...Meyers
Office: UNR
FXUS63 KUNR 302318
AFDUNR
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
418 PM MST Sun Nov 30 2025
.KEY MESSAGES...
- Minor chances for light snow this evening/overnight along Neb
border
- Potential upslope snow event northern Black Hills Tuesday
afternoon through Wednesday afternoon
- Northwest flow will keep temps below seasonal norms through the
week
&&
.DISCUSSION...(This Evening Through Sunday)
Issued at 125 PM MST Sun Nov 30 2025
Latest analysis shows upper level split flow regime across much of
the CONUS, with weak shortwave ridging taking place in the
northern stream across southern Sask/Manitoba dropping into ND,
with a 500hpa shortwave trof/impulse in the southern stream
dropping into western WY with expansive cloud shield across
eastern WY into southwest SD. At the surface, the arctic high
pressure responsible for the chilly/record setting cold of this
morning was located across central SD. Low pressure was located in
northern UT with a surface trough nosing to the northeast into
south central WY. Weak radar returns are showing up across far
southwest SD, but scanning local webcams doesn’t show much, so if
anything is reaching the ground, its flurries at best.
As the southern stream 500hpa wave conts to drop south through the
next 24 hours, weak 700hpa theta-e forcing remains along the SD/NE
border through 12z Monday. Moisture still remains pretty meager
with this system, but anticipating that the air will be cold
enough to wring anything out with minor forcing and ascent due to
wave passing to the south. With returns already being seen on
radar, will continue to minor pops along the border with little in
the way of accums/QPF.
Monday should be a quiet day with warmer...albeit still below
normal...temps. Tuesday is where the next forecast challenge
lies. Models are trending a bit cooler than previous runs, and
next upper trough drops through the region. LREF mean 2 meter
temps on Tuesday are now around a category cooler than current
forecast has going. Deterministic 850hpa temps are also a bit
cooler than when compared to 24 hours ago. Additionally, surface
cold front comes through a bit stronger and earlier than
previously thought, lending itself to a potential upslope snow
event for the northern Black Hills. LREF is showing total snow
accums probabilities of > 2” through 00z Thursday from 30-50% for
parts of the northern Black Hills. Minor accums are possible on
the plains...as probabilities of > 0.5” snow on the plains vary
from 20-30%. It will also become breezy/windy on backside of cold
front Tuesday afternoon through Wednesday with temps again
dropping on Wednesday.
Temperatures try to rebound a bit for Thursday and Friday, but
will fall again for the weekend as another impulse slides south
dragging a cold front with it. This will bring another shot of
light snow, especially to the northern Black Hills.
&&
.AVIATION...(For the 00Z TAFS Through 00Z Monday Evening)
Issued At 415 PM MST Sun Nov 30 2025
Local MVFR/IFR conditions near KICR will slowly improve this
evening. A few light snow showers possible across the SD/NE border
after 00z, with transient MVFR conditions possible. Otherwise, VFR
conditions will prevail across the forecast area.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&
$$
DISCUSSION/KEY MESSAGES...Hintz
AVIATION...SE
Office: ABR
FXUS63 KABR 302339
AFDABR
Area Forecast Discussion
National Weather Service Aberdeen SD
539 PM CST Sun Nov 30 2025
.KEY MESSAGES...
- Below normal temperatures continue through the 7 day forecast,
interrupted a couple of times by brief warm-ups Tuesday and
again Thursday. Coldest timeframes appear to be Monday,
Wednesday and next Sunday with temps 10 to 20 degrees below
normal. Wind chills as cold as 15 to 25 degrees below zero are
forecast for Thursday morning and next Sunday morning.
&&
.UPDATE...
Issued at 532 PM CST Sun Nov 30 2025
Stratus continues to expand north and east. Under this layer we're
seeing some flurries as this moisture is in the DGZ. No other
changes of note.
See below for an updated aviation discussion.
&&
.DISCUSSION...
Issued at 119 PM CST Sun Nov 30 2025
At 1pm CST, skies are partly to mostly sunny. Skies have cleared
off across northeast South Dakota/west central Minnesota and a
portion of north central South Dakota. Surface high pressure is
centered over the CWA, so mixing winds to eradicate the low clouds
are rather limited. Temperatures are clinging to single digits to
mid teens across the region on light north to northwest winds
generally less than 10 mph.
Surface high pressure will gradually slide southeast out of the area
tonight, with surface winds responding by becoming south/southwest.
Low clouds across southern/western South Dakota should begin to
advect north-northeastward overnight in response to the changing
pressure/wind direction. The low pressure system lifting out of
Wyoming/Colorado in the morning could end up bringing enough
synoptic-scale lift through the southern half of South Dakota to
deepen the stratus (or saturate enough of the column for a couple of
hours) layer (top of stratus forecast to be in the DGZ around -12C
to -14C) and generate more flurries/very light snow for a couple
of hours from early morning (Pierre area) through mid-day Monday
(Watertown area). Ensemble-based PoPs do not "see" this brief
light snow potential. Will leave it as a game-time decision for
the next mid-shift whether to introduce a small/brief snow PoP.
From Monday afternoon through the end of Monday night, a surface
warm front will be moving into the Dakotas, and low level thermal
progs do show some WAA happening (a non-diurnal temperature trend
perhaps for Monday night?).
The extended forecast is dominated by northwest flow in a positive
PNA pattern (upper ridge western CONUS/upper trof eastern CONUS).
Doubtless, there are occasions when an upper level wave is sweeping
through the region in said upper flow. But, other than Tuesday night
(20-30 percent chance of precipitation), the forecast does not
contain any precipitation mention until day 6 (Friday
night/Saturday). For the most part, the ensemble qpf clusters are
dry and ensemble 500hpa clusters and deterministic GSM's suggest
limited opportunity for measurable precipitation in the out periods.
Deterministic GSM's low level thermal advection progs highlight
Tuesday and Thursday/Friday as being potential periods of low level
WAA, while the rest of the period is dominated by neutral air or low
level CAA. Ensemble 850hpa temperature anomalies suggest most of the
period is running near to below normal for temperature. The high
amount of spread in the 25th to 75th temperature percentiles (any
where from 5 degrees to, in many instances, more than 10 degrees of
spread) continues, making it difficult right now to put any
semblance of confidence in the potential for a warm up this
Tuesday and Thursday. Currently, wind chill temperatures are
forecast to dip below -15F Thursday morning and Sunday morning.
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 532 PM CST Sun Nov 30 2025
Terminals KABR,KATY,KPIR,KMBG
An MVFR cloud deck has moved into KMBG/KPIR/KABR, and eventually
into KATY. This will persist through the night, moving off during
the day Monday. Winds will gradually increase and remain
predominantly out of the south southwest.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...07
DISCUSSION...10
AVIATION...07
