764
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