sd discuss
Office: FSD
FXUS63 KFSD 011740
AFDFSD
Area Forecast Discussion
National Weather Service Sioux Falls SD
1140 AM CST Mon Dec 1 2025
.KEY MESSAGES...
- Wintry cold continues through the upcoming week. Morning low
temperatures fall into the single digits with nighttime wind
chills below zero.
- Scattered light snow may bring minor travel impacts south of
I-90 toward US Highway 20 this morning through afternoon. High
confidence that most locations will see under a half inch of
new snow.
- 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.
- Details remain uncertain, but additional snow chances continue
into the weekend. Regardless colder temperatures prevail.
&&
.DISCUSSION...
Issued at 304 AM CST Mon Dec 1 2025
TODAY-TONIGHT: Haven't seen much in the way of fog develop this
morning, although some of the hi-res guidance continues to show the
potential for some through the valleys and along the Buffalo Ridge.
Given trends, think that stratus and some patchy flurries prevail
through the morning over any fog development, but can't entirely
rule out some isolated fog. Snow chances later this morning and into
the afternoon have trended a bit further to the south, so did trend
closer to US Hwy 20. Amounts remain less than half an inch.
Think that we'll see stratus stick around much of the day especially
east of I-29 so remained a bit more pessimistic with highs, keeping
us in the teens and 20s. Southerly winds this afternoon may gust
around 20 mph. Winds become light tonight with surface high pressure
moving into the area. Stratus should clear out, or at least diminish
in coverage, with lows tonight in the single digits either side of
0F. We might see a few locations stay a bit warmer if stratus
redevelops or lingers later into tonight. HREF and some hi-res
guidance show the potential for fog to develop again tonight, but
confidence is low.
TUESDAY-WEDNESDAY: A relatively warmer day expected Tuesday with
southerly flow and increased WAA. Robust cold front moves through
the northern and central Plains later in the afternoon into the
evening. Flurries to light snow are possible as the front moves
through, with guidance trending up a smidge in QPF and a bit faster.
A handful of 01.00z CAMs show some light snow moving into the US Hwy
14 corridor by the mid/late afternoon hours, moving east into
Tuesday night. Depending on how quickly the front moves through and
if precipitation is slightly preceding it, can't rule out some
mixed precip during the afternoon and early evening, especially if
we warm into the 30s west of the James. Much colder air and stronger
winds move in behind the front. If we see new light snow
Tuesday/Tuesday night, strong winds may lead to some patchy blowing
snow for the Wednesday morning commute. Increased pops and QPF a bit
from the NBM. With the quick moving front, amounts should remain
light.
With the strongest push of CAA through the day on Wednesday, we'll
see much colder temperatures Wednesday night into Thursday as Arctic
high pressure slides in. Lows Wednesday night look to be the coldest
of the week, falling into the single digits and teens below zero.
Even with light winds, wind chills may plummet to around 20 to 25
below 0F.
LATE WEEK ONWARD: Ridging breaks down over the Pacific, taking us
from more northwesterly flow to zonal flow. We'll see a few
shortwaves move through the pattern with a stronger wave Saturday.
Guidance has trended into a bit more agreement, so started trending
pops up slightly for Saturday. A lot can and will still change, so
keep an eye on the forecast if you have travel plans across the
Plains and Upper Midwest. Regardless of snow chances, temperatures
remain near to below average late week and through the weekend.
&&
.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1139 AM CST Mon Dec 1 2025
Patchy MVFR conditions will remain possible into the afternoon,
with the better chances over parts of northwest IA. Otherwise
VFR conditions are expected.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&
$$
DISCUSSION...SG
AVIATION...08
Office: UNR
FXUS63 KUNR 011656
AFDUNR
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
956 AM MST Mon Dec 1 2025
.KEY MESSAGES...
- Northwest flow aloft will push disturbances through the region
through next weekend
- Best chance of accumulating snow will be over the northern
Black Hills courtesy of northwesterly upslope flow
&&
.DISCUSSION...(Today Through Sunday)
Issued at 216 AM MST Mon Dec 1 2025
09z surface analysis had chilly high over the Midwest with return
flow for the CWA ahead of a developing warm front laid out from
eastern MT into CO. Water vapour loop showed upper trough moving
southeast of the CWA with northwest flow behind it. Regional radar
loop/webcams suggest a few flurries over south-central SD, which
should end by sunrise.
Today/tonight, warm front moves through as winds develop a
westerly component behind it. Temperatures will be near guidance
given downslope flow, even for folks with deeper snow cover.
Tuesday/Wednesday, upper trough races from Canada through the
plains. Energy will split with one shortwave passing to our
northeast with weak QG-forcing and another passing well to our
southwest. Cold front with modest moisture/frontogenesis moves
through, which will be the main forcing mechanism for QPF on the
plains. Precipitation east of the Black Hills will mix with rain
Tuesday afternoon, but mostly snow elsewhere and then all snow
behind the cold front. For the northern Black Hills, Froude
numbers >1 by Tuesday evening with 0-2km RH reaching 90%. A good
setup for upslope-enhanced snowfall. Latest LREF guidance
suggests several at least a couple inches of snow (>70% chance
>0.10" QPF). <30% chance of >0.10" QPF on the plains. Not thinking
Winter Weather Advisory headlines at this point with total QPF
chances >0.25" <30%. High resolution deterministic guidance more
bullish, however, so will take a close look at the latest guidance
today. Relatively mild temperatures Tuesday are squashed behind
the cold front Tuesday night leading to highs 10-20F below normal
for Wednesday.
Additional disturbances move through Thursday night to the
weekend with the northern Black Hills favored for the best QPF.
The plains best chance will be Friday night/Saturday when synoptic
forcing perks up. Didn't stray from guidance for temperatures,
but spreads do expand quite a bit at the end of the period giving
low confidence for "mild" vs "cold".
&&
.AVIATION...(For the 18Z TAFS Through 18Z Tuesday)
Issued At 955 AM MST Mon Dec 1 2025
VFR conditions will prevail through the period.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&
$$
DISCUSSION/KEY MESSAGES...Helgeson
AVIATION...Smith
Office: ABR
FXUS63 KABR 011703 AAC
AFDABR
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1103 AM CST Mon Dec 1 2025
.KEY MESSAGES...
- Breezy southerly winds will lead to subzero wind chills through
midday. An area of enhanced southwest winds across the Sisseton
Hills today could lead to some patchy blowing snow.
- A quick moving disturbance will push through the region the latter
half of Tuesday into early Wednesday and kick off some light
precipitation in the form of snow and a wintry mix.
- Very cold air across the region Wednesday night, with lows in
the single digits below and teens below zero. Wind chills may
reach 25 below to 30 below zero in the James River valley.
- Show chances (20-30%) return Friday night/Saturday as another
clipper system potentially moves through.
&&
.UPDATE...
Issued at 1100 AM CST Mon Dec 1 2025
See below for an aviation forecast discussion for the 18Z TAFs.
UPDATE Issued at 901 AM CST Mon Dec 1 2025
No appreciable updates planned to the today period forecast.
UPDATE Issued at 539 AM CST Mon Dec 1 2025
The aviation discussion has been updated for the 12Z TAFS.
&&
.SHORT TERM /TODAY THROUGH TUESDAY AFTERNOON/...
Issued at 443 AM CST Mon Dec 1 2025
A mixture of clear skies and low stratus early this morning across
the forecast area. Southerly low level flow has led to low stratus
streaming northward and downwind of Lake Oahe and nearby sections of
central SD. There could perhaps be a few flurries associated with
this but haven't seen any evidence yet from sfc obs and SDDOT
webcams. Seems as if winds remain stirred enough to prevent any fog
development, but something to watch the next few hours. Other low
stratus is shifting northeast across northeast SD and west central
MN.
Sfc high pressure ridge will continue drifting farther away from our
forecast area early this morning which will promote an increase in
southerly breezes through midday. As a result, subzero wind chills
will still remain present. Hi-res guidance does point to gusty
southwest winds developing across the Sisseton Hills and downslope
area by mid morning through late afternoon or early evening. Did
increase winds speeds and gusts in that area but not enough to kick
off much for blowing snow. It'll be something the incoming day shift
will have to keep an eye on for further adjustments to the forecast
if needed. An upper trough axis will swing southeastward across the
region today. A few flurries may be possible as far north as the I-
90 corridor in our far southern zones in south central SD through
the early morning hours and perhaps beyond daybreak but mostly dry
conditions will be the rule across most of the CWA today.
Temperatures will remain rather chilly, especially across areas that
have a deeper snowpack. Teens for highs will be prevalent from
portions of central and north central SD into northeast SD and west
central MN. Some low level WAA will aid in afternoon readings
reaching the low to mid 20s south and west of the Pierre area.
A warm front approaches the region tonight into Tuesday morning.
Clear to partly cloudy skies early on through the evening will allow
temperature readings to fall quickly into the single digits above
and below zero. HREF probs for temperatures colder than 0F range
from 40-80 percent across north central and northeast SD into west
central MN. Clouds increase from west to east tonight into early
Tuesday. Depending on how quickly they increase will play a factor
in how quickly temperatures fall tonight. We might see readings
stabilize or increase a bit closer to daybreak Tuesday. That warm
front is all part of the next disturbance that will shift east into
the Dakotas during the day. There will be enough moisture for this
clipper like system to work with to produce a round of light snow
and perhaps a rain/snow/sleet mixture closer to midday and afternoon
hours. At this point, QPF values remain light, so not anticipating
anything too heavy, but a light coating of snow will be possible for
some areas by late in the afternoon. How quickly that warm front
moves through our area will dictate how warm temperatures get.
Central SD has a shot at readings in the low to mid 30s. Some
question remains though farther east and in areas that have the
deepest snowpack. Nonetheless, at least highs in the 20s look
probable.
&&
.LONG TERM /TUESDAY EVENING THROUGH SUNDAY/...
Issued at 443 AM CST Mon Dec 1 2025
Tuesday night will still be dealing with the passing low pressure
and associated warm front/cold front passages and resultant
snow/mixed precip chances. Continued the trend from the short term
with increasing PoPs across the region. Grand Ensemble shows a large
area of 40-70% chances for measurable precipitation in a 6-hr period
ending at 06Z Wednesday. Highest chances show up on the Coteau
region. Did raise PoPs slightly more into the 30-50% range across
much of the CWA for Tuesday evening before chances decrease quite a
bit beyond 06Z Wednesday. Cannot rule out light snow accumulations
continuing into Tuesday evening, but Grand Ensemble showing only
<20% chance of seeing anything more than a half inch. Thermal
profiles/surface temperatures would support mixed precip across
central SD, although rather light QPF generally less than a tenth
(90th percentile) likely.
Cold front will also be moving through the region Tuesday night,
with a surface high building into the day Wednesday. Much colder air
with 925mb temps likely from -15C to -17C across the area during the
day Wednesday. Current forecast highs are only in the teens. But
it's Wednesday night when the heart of the cold air settles in as
lows drop into the single digits below and teens below zero.
Interesting to note current apparent T forecast is in the 25 below
to 30 below range in the James River valley 06Z to 12Z Thursday.
GEFS/ENS/GEPS 6-hr mean MSLP and mean 6-hr precip shows another
clipper system potentially sliding southeast across the High
Plains/Northern Plains Friday night into Saturday, with inherited
chances generally in the 20-30% range.
&&
.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1100 AM CST Mon Dec 1 2025
Terminals KABR,KATY,KPIR,KMBG
VFR conditions look to persist for the most part during this TAF
cycle. Breezy conditions at times will be possible with strongest
gusts of 20-25 knots at KATY. This afternoon, once winds become
a bit more westerly at KMBG and KPIR, there could be some gusts up
to 20 knots.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...10
SHORT TERM...Vipond
LONG TERM...TMT
AVIATION...10
