sd discuss
Office: FSD
FXUS63 KFSD 090448
AFDFSD
Area Forecast Discussion
National Weather Service Sioux Falls SD
1048 PM CST Mon Dec 8 2025
.KEY MESSAGES...
- Confidence remains high in strong winds impacting the area for
Tuesday through Wednesday morning. A Winter Storm Watch for
Blizzard conditions has been issued for the vast majority of
the area. A High Wind Warning has been issued for Gregory,
Charles Mix, and Brule counties. Winds up to 50 to 60 mph is
expected in both headlines. Blowing snow will be the main
impact where visibilities down to a quarter of a mile is
possible.
- Chances for snow will persist throughout the week and into the
weekend. At this time, snowfall amounts look to be light with
each chance.
- Much colder temperatures are expected from the middle of the
week through the weekend. Cold Weather headlines may be
needed.
&&
.DISCUSSION...
Issued at 318 PM CST Mon Dec 8 2025
Low level stratus and fog persists across the area this afternoon.
The fog is being driven by weak southerly moisture advection,
keeping the boundary layer saturated. The stratus and fog have begun
to nudge eastwards as low level winds begin to take on a more
westerly component thanks to an advancing warm front. Thus, have
left the Dense Fog Advisory in effect through 10 pm for locations
along and east of I-29. Trends will be monitored through the rest of
today to see if any further reductions are needed in the Advisories
extent. Tonight will be quiet with low temperatures falling to the
20s to up to about 30F.
Things begin to change on Tuesday as a strong upper level shortwave
trough pushes through the Northern Plains. This will bring a round
of precipitation to the area beginning Tuesday morning. Precipitation
looks to begin as light freezing rain before transitioning to plain
rain as temperatures warm through the morning hours, thanks to
persistent warm air advection (WAA) aloft. A few places might see a
light glaze of ice for a brief period of time during the morning and
early afternoon hours before plain rain melts away the ice. The
afternoon will still see some cooler temperatures across the area
thanks to persistent cloud cover and current snowpack across the
majority of the area. Have highs only warming to the mid 30s east of
the James River up to the 40s and 50s west of the River. The bulk of
the rain will push east of the area by the late afternoon hours. The
other component to Tuesday will be strengthening winds during the
afternoon hours as a strong cold front will pushes through the area.
A strong shot of cold air advection (CAA) is expected with the
passing front, resulting in very strong winds across the entire
area. The strongest winds will come during the evening and overnight
hours where gusts up to 50 to 60 mph is likely (>=70% chance). These
strong winds will be capable of blowing the current snow pack around
which can result in blowing snow across most of the area. The main
uncertainty regarding the extent of the blowing snow is due to the
previously mentioned rain and temperatures warming above freezing.
The rain and warmer temperatures will likely melt some of the snow
pack. Even with the quickly falling temperatures behind the front,
questions remain how blowable the snowpack will be. As such, have
issued a Winter Storm Watch for Blizzard Conditions from noon on
Tuesday through noon Wednesday. A High Wind Warning has been issued
for Gregory, Charles Mix, and Brule counties due to these counties
having a much lower snowpack to non existent snowpack. The High Wind
Warning is in effect from noon Tuesday through 3 am Wednesday.
Winds will be weakening during the morning hours on Wednesday as
high pressure slides through the Northern Plains. Tuesday will be
the last "warm" day across the area before a much colder airmass
settles into place for the rest of the week. Highs will be below
average in the 20s to down to the teens and single digits come
Friday through the weekend. With such cold temperatures in place
along with light winds in place, Cold Weather headlines may be
needed. Highs may trend back towards seasonable come early next
week.
For precipitation chances, there looks to be persistent chances for
snow throughout the week. Currently, the highest chances (30-40%)
for snow looks to come on Thursday. Though additional chances will
persist through the weekend. Given how these are all clipper
systems, light snowfall is most probable with each passing clipper
at this time.
&&
.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1047 PM CST Mon Dec 8 2025
VFR ceilings will begin this period, but last only a short while as
the next storm system moves in this morning. By mid-to-late morning
we'll begin to see ceilings decrease to MVFR and lower along Highway
14. Lower ceilings will progress south with the system.
After sunrise a storm system will move into the area from the
northwest. Areas along and north of Highway 14 will likely see a
wintry mix including freezing rain/drizzle. Ice accumulations are
expected to remain low, a light glaze to a hundredth of an inch. As
the storm drifts southeast through the late morning, precipitation
will transition over to light rain and expand in geographic
coverage. Rain slowly tapers off from west to east in the early
evening. Rain will linger over southwest Minnesota and northwest
Iowa this evening, eventually transitioning back to snow. This will
then taper off after midnight.
Light and variable winds overnight will begin to increase after
sunrise Tuesday morning. Winds will then become westerly, then
northwesterly behind a strong cold front (associated with the
previously mentioned storm) that passes through the region beginning
in the late morning. Winds will increase drastically over a short
period of time. Widespread gusts of 25-40 kts are expected by
09.21Z. Winds continue to increase and by 10.00Z gusts of 40-45 kts
will be common region wide with a few 50+ kt gusts possible. Gusts
of this magnitude are expected to continue through the end of the
period. Some reductions in visibility due to blowing and drifting
snow are likely. In addition, LLWS is expected at all three TAF
sites beginning after noon. Speed shear up to 50 to 55 kts are
expected and will continue past the end of the period.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...Winter Storm Watch from Tuesday evening through Wednesday
morning for SDZ067-070-071.
Winter Storm Watch from Tuesday afternoon through Wednesday
morning for SDZ038>040-052>056-058>062-064>066-068-069.
High Wind Warning from noon Tuesday to 3 AM CST Wednesday for
SDZ050-057-063.
MN...Winter Storm Watch from Tuesday evening through Wednesday
morning for MNZ080-081-089-090-098.
Winter Storm Watch from Tuesday afternoon through Wednesday
morning for MNZ071-072-097.
IA...Winter Storm Watch from Tuesday evening through Wednesday
morning for IAZ001>003-012>014-020>022-031-032.
NE...Winter Storm Watch from Tuesday evening through Wednesday
morning for NEZ013-014.
&&
$$
DISCUSSION...Meyers
AVIATION...AJP
Office: UNR
FXUS63 KUNR 090505
AFDUNR
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1005 PM MST Mon Dec 8 2025
.KEY MESSAGES...
- Mild, dry and breezy this afternoon. Wind gusts occasionally up
to 45 mph possible
- Strong winds likely Tuesday. A High Wind Warning is now in
effect for most of western SD
- Turning colder with chances for light snow across the region
Wednesday through Friday
&&
.UPDATE...
Issued at 803 PM MST Mon Dec 8 2025
Have upped wind speeds over northeastern WY per latest
deterministic guidance in combination with earlier probabilistic
guidance. 00z NAM Bufkit soundings/HRRR suggest high wind warning
winds over northeastern WY Tuesday, but MOS not as excited with
best isallobaric forcing (4-5mb/3hr pressure rises) over western
SD. NBM depicts <20% chance of >=58mph gusts for northeastern WY.
Western SD plains have the expected high probabilities. Thus, the
current wind headlines look good. Midnight shift can take one
more look before strong cold front arrives.
&&
.DISCUSSION...(This Evening Through Monday)
Issued at 1247 PM MST Mon Dec 8 2025
Rest of today...Not much going on across the region this
afternoon. A weak wave is passing through which has kicked up the
winds a bit over the last hour. These breezy conditions will
continue for several more hours before they diminish. Winds could
occasionally gust up to 45 mph with mild temperatures.
Heading into Tuesday morning a stronger area of low pressure will
bring a surface front through the region during the early morning
hours and ahead of the main wind event. This will provide a window
for some light snow or a rain/snow mix to occur across the
northwestern portions of the area. Expecting a quick transition to
all rain as the strong downsloping winds develop which will
quickly warm temperatures. This area of low pressure will slide to
the SE across central ND and SD Tuesday. A belt of 55-60 not winds
will overspread the region quickly and winds are expected to turn
gusty rather quickly during the morning hours on Tuesday. a suite
of HI-RES models have come in a bit stronger with these winds
aloft around the 850mb level showing a concentrated area of 70+
knot winds across the eastern plains. While these winds aloft are
impressive the strong CAA advection we were expecting has not been
pushed off to the north and east and this will limit some mixing
down of these winds. But precipitation post frontal boundary will
linger across the region in the form of banded lines of rain
showers. These will be a concern as locations under these areas of
precipitation may see sudden bursts of rain/snow, snow or, graupel
as well as strong wind gusts as those strong winds aloft will mix
down with the precipitation. Outside of that, much of western SD
and the eastern Plains will experience strong winds throughout
much of the day on Tuesday with wind gusts commonly exceeding 60
mph with a few locations seeing wind gusts at or over 65 mph.
Given this a High Wind Warning is now in affect for Tuesday
morning through late Tuesday night.
Another system is on the heels with the exiting system with
unsettled weather expected to persist Wednesday through the rest
of the week. Models are beginning to settle in on the overall long
wave pattern but the mesoscale parameters that will determine how
quickly we transition to all snow, how strong the CAA will be and
surface flow still need to be ironed out to pinpoint just how much
snow will fall and where the heaviest snow will occur. The
overall consensus at this time is for widespread snow looks
likely with light accumulations possible. With this pattern shift
temperatures are also expected to turn colder as CAA eventually
advects into the region. This will drop highs into the upper teens
to lower 20s with overnight lows in the single digits.
&&
.AVIATION...(For the 06Z TAFS Through 06Z Tuesday Night)
Issued At 1005 PM MST Mon Dec 8 2025
VFR conditions are expected through 09/12z. A strong cold front
will move through Tuesday bringing strong, gusty northwest winds
behind it, reaching 50-55kts on the western SD plains at times
after 09/15z. Areas of MVFR/IFR conditions due to lower
clouds/ra/sn will affect northeastern WY/northwest SD behind the
front. Mainly VFR conditions expected over southwest into south-
central SD.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...High Wind Warning from 8 AM MST /9 AM CST/ Tuesday to 2 AM MST
/3 AM CST/ Wednesday for SDZ001-002-012>014-025>027-030>032-
041>044-046-047-049-072>078.
WY...High Wind Warning from 8 AM Tuesday to 2 AM MST Wednesday for
WYZ060.
&&
$$
UPDATE...Helgeson
DISCUSSION/KEY MESSAGES...Woodward
AVIATION...Wong
Office: ABR
FXUS63 KABR 090516 AAB
AFDABR
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1116 PM CST Mon Dec 8 2025
.KEY MESSAGES...
- Next clipper will most likely (60-90% chance of occurrence) be
preceded by a period of light freezing rain Tuesday morning before
temperatures warm above freezing Tuesday afternoon across northeast
SD/western MN.
- Northwest winds Tuesday afternoon and evening could gust in excess
of 50 to 60 mph across central and north central South Dakota. 45 to
55 mph gusts for the northeast Tuesday evening/overnight.
- By the end of the week, colder air is expected to move in. High
temperatures will be near to just above 0 degrees, with overnight
lows as low as the teens below zero. Wind chill values Friday and
Saturday morning could be as low as -20 to -30 degrees.
&&
.UPDATE...
Issued at 520 PM CST Mon Dec 8 2025
Forecast remains on track this evening. No major changes planned.
&&
.SHORT TERM /THIS EVENING THROUGH TUESDAY NIGHT/...
Issued at 244 PM CST Mon Dec 8 2025
Cleared out in central/north central South Dakota, and winds have
shifted to the southwest. Focus for the afternoon remains on the
downslope potential for the Sisseton hills region. Peever has
shifted around to the southwest now as well, though winds remain
weak. HRRR still shows in the 2 to 4 pm timeframe winds will
increase to about 40 mph, lasting through about 8 pm before
weakening. Reissued the SPS for these downslope conditions later
this afternoon.
Focus shift to tonight/Tuesday morning. CAMS and NBM are fairly
confident in regards to moisture moving in, and profiles/NBM
continue to support freezing rain as the predominant p-type before
temperatures warm above freezing. NBM/HREF also showing confidence
in this warming, with just a 1-3 degree range between the 25th/75th
percentiles.
The focus then shifts towards high wind potential. 1/2km winds are
about 50kts, and in BUFKIT low level profiles cool in the cold
advection regime quickly after 21-03Z timeframe, with 60kts at the
top of that mixed layer (about 1km). High wind warning has been
issued in regards to these winds.
But when it comes to wrap around, still not very confident we will
see enough to present a blowing snow hazard. NBM QPF is only a few
hundreds, after midnight post peak wind speeds. In regards to the
blizzard possibility, according to the blowing snow model, we'll
need to see snowfall rates exceeding 1/2" per hour to get visibility
to 1/4 mile at temperatures at about 30F, which is not a rate we are
seeing from guidance. Additionally, from NAM BUFKIT soundings, cold
advection low level profiles with moisture at the top of the mixed
layer is still warmer than the dendritic growth zone, meaning low
moisture/clouds may be too warm still to generate snow. GFS BUFKIT
profiles do have the snow, but by the time we get wrap around 03-07Z
mixed winds are dropping off rapidly.
The other question is will the snow on the ground be blowable? Rain
and mild temperatures are expected to cap the snow with a crust,
though there is some discussion as to whether 60 mph gusts will be
capable of breaking up this crust. Unfortunately, it remains to be
seen and this is something we will have to watch for tomorrow
evening.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Issued at 244 PM CST Mon Dec 8 2025
Wednesday morning starts a rather busy long term period with some
much colder air moving into the region. Along with the colder air,
we have several opportunities for snow this week and potentially
into the weekend. And, along with the colder air and snow, we have
some good strong winds. Quite the combination of weather phenomena
in store.
To start, we have several shots of upper level energy move through
the region this week. The first will be Wednesday morning. This is
behind the Tuesday low. Winds will be diminishing through the early
morning hours and we are left with just much colder air.
Temperatures at 6 PM Tuesday at 850mb are between -1 and 2 degrees
C. By 6 AM Wednesday, 850mb temps have dropped to -12 to -13
degrees along and east of the James River. The second shot of
energy moves in early Thursday morning as another clipper system.
This will bring in some slightly warmer air and also another chance
for some snow. At the moment, we aren't expecting a lot of snow,
chances for more than an inch are highest over northeastern SD at
between 40 and 60% and chances for more than 2 inches is around 40%.
Some light snow could linger into Friday morning. Friday and
Saturday are expected to be the coldest of the period behind the
Thursday clipper with 850mb temps forecast to be in the upper teens
to 20s below zero C. This translates to surface temps in the single
digits, potentially single digits below zero for far northeastern
SD. Another shortwave moves across on Saturday bringing potential
for another inch or so of snow. High pressure moves through early
Sunday morning ahead of yet another trough reaching down from
Canada. This will bring winds from the south and a shot of WAA to
bring us back up into the teens across most of central and
northeastern SD.
&&
.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1116 PM CST Mon Dec 8 2025
Terminals KABR,KATY,KPIR,KMBG
Conditions will deteriorate late tonight through Tues morning as
MVFR/IFR cigs spread over the region with the next winter storm.
Frza will be a concern east of the Missouri in the morning before
temps rise. Then westerly winds increase with gusts of 40 to 50
kts at KMBG and KPIR.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...High Wind Warning from 3 PM Tuesday to 6 AM CST Wednesday for
SDZ006>008-011-018.
High Wind Warning from 11 AM Tuesday to 2 AM MST Wednesday for
SDZ003-015.
High Wind Warning from 3 PM CST /2 PM MST/ Tuesday to 3 AM CST
/2 AM MST/ Wednesday for SDZ004-005-009-010-016-017-033>037-
045-048-051.
Winter Weather Advisory from 6 AM to noon CST Tuesday for
SDZ005>008-010-011-018>023.
High Wind Warning from 6 PM Tuesday to 6 AM CST Wednesday for
SDZ019>023.
MN...Winter Weather Advisory from 9 AM to 3 PM CST Tuesday for MNZ039-
046.
High Wind Warning from 3 PM Tuesday to 6 AM CST Wednesday for
MNZ039-046.
&&
$$
UPDATE...20
SHORT TERM...07
LONG TERM...13
AVIATION...20
