sd discuss
Office: FSD
FXUS63 KFSD 080455
AFDFSD
Area Forecast Discussion
National Weather Service Sioux Falls SD
1055 PM CST Sun Dec 7 2025
.KEY MESSAGES...
- Narrow band of light snow will move from west to east through
the region into the early overnight hours. Amounts of snow
generally stay less than 0.5" with pockets near 1" in the
Buffalo Ridge.
- A busy week is ahead with a risk of precipitation nearly
every 1.5 days. Most of the precipitation events this will
remain light, but systems on Thursday and Saturday will bear
watching.
- Confidence is high that winds Tuesday night into Wednesday may
exceed advisory criteria with potential for 55+ mph winds in
a few areas. We'll need to monitor the snow pack and air temps
closely to monitor blowing snow potential.
- Confidence is also moderate that arctic air will bring near
advisory level wind chills to the region by next weekend.
&&
.DISCUSSION...
Issued at 204 PM CST Sun Dec 7 2025
THIS AFTERNOON: A minor shortwave continues to move across the
Dakotas early this afternoon, with the combination of dPVA and warm
advection leading to light snow. The greatest intensity of snow
thus far has been tied directly to the stronger lobe of vorticity,
with weaker echoes associated with the broad warm advection. This
activity will track steadily east into the evening, with snowfall
amounts less than 0.5" in many areas.
TONIGHT: The favored track of mid-lvl vorticity southeast along the
Buffalo ridge will keep a risk for snow through the higher
elevations into the overnight hours. It's possible a few areas could
see up to an inch of very fluffy snow by time the wave moves east
after midnight. Elsewhere, stratus will prevail under broad
warm advection AOA 850mb. Surface temperatures may begin to warm
through the night, with no strong drops expected.
MONDAY: Mid-lvl ridging builds on Monday with broad warm advection
spreading throughout the Upper Plains. While temperatures aloft may
warm well above freezing, we may struggle to realize these
temperatures given weaker southerly to southeasterly surface flow,
lingering stratus, and fresh snow cover. Have trended forecast
temperatures a bit lower over snow cover areas, with highs in the
upper 40s in south central SODAK. One thing to watch will be minor
blowing snow along the higher elevations of the ridge given
favorable surface wind fetch.
TUESDAY-TUESDAY NIGHT: An active pattern will continue to send
multiple shortwave through the Northern US for much of the upcoming
7 day forecast. One such wave crosses the Canadian Rockies and
moves into the Upper Plains late Monday night. Persistent warm
advection ahead of this wave, along with southwesterly breezy
surface winds, will advect near to above freezing temperatures into
the Tri-State area by Tuesday morning. Again, minor
blowing/drifting snow could be possible Tuesday morning. This wave,
given favorable jet dynamics is expected to rapidly intensify
as it crosses North Dakota and northern Minnesota Tuesday, with
widespread precipitation well north of the CWA. Closer to home,
breezy to gusty westerly winds surge temperatures over the snow
pack towards the 40 degree mark, which should help settle the
fresh snowpack. As the wave passes Tuesday afternoon and
evening, scattered rain showers in the warm advection regime
likely develop along and north of I-90.
The passing surface low near the Twin Cities at 00z Wednesday will
surge an initial front through the CWA early in the evening, marking
the arrival of very strong cold air advection aloft. The true
surface front may lag a few hours later, and will gradually lower
temperatures through the night. A BIG concern with this system is
the rapid deepening of the upper low and development of a channel of
50 to 60+ knot low level winds on the western side of the clipper.
These low-lvl winds, at their current projected intensity, fall
outside the 30 year, 3-week climatology for this time of the year.
Raw model guidance would support gust of 45 to 55 mph over a large
portion of the CWA, and have again significantly boosted winds over
the populated NBM. High wind watches may be needed in some areas,
but will subsequent shifts to reexamine. This strong but short-
lived burst of wind poses an uncertain risk to the existing snowpack
and the ability to loft it. It's uncertain just how long we'll stay
above freezing Tuesday, and if this will be long enough to stabilize
the very fluffy nature of the snow. Blowing snow tools suggest that
if temperatures remain above 34 degrees for an extended time
snow may struggle to sufficiently loft across a widespread area.
However the concern would be as temperatures fall back below
freezing into Wednesday morning and moisture is again pulled out
of the snow. Also, if we see even higher sustained wind gusts
breaking the 45 knot mark, snow pack temperature may matter even
less as lofting probabilities cross the 50% threshold no matter
the age of the snow. All that said, continue to stay weather
aware if traveling Tuesday night into Wednesday.
WEDNESDAY-SATURDAY: This stagnant pattern continues through the
upcoming weekend, keeping a persistent risk for snow moving into the
region about every 1.5 days. After temperatures fall back into the
teens Wednesday, we'll watch another wave arrive by Thursday. Model
trends have swayed back towards more of a lighter nuisance event
moving through the Tri-State area Thursday. A deeper and more
meridional tracking wave them moves through the Plains and
Great Lakes at the end of the week increasing confidence of a
fairly strong and gusty arctic air intrusion into the upcoming
weekend. Friday morning and Saturday morning would be potential
targets of concern for wind chill values near advisory levels.
Confidence starts to go out the window by next weekend as this
persistent northwesterly flow pattern may or may not send another
shortwave into the region. As typical in this pattern, medium
range guidance and ensembles are wildly variable in their solutions.
Best word of advice through this week is to continue to monitor the
forecast if traveling.
&&
.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1055 PM CST Sun Dec 7 2025
A band of light snow showers east of I-29 will continue to push east
through the early morning hours of Monday. Stratus will linger
through the first half of the period, with MVFR to IFR ceilings
prevailing. Around sunrise, low stratus to patchy dense fog will
result in a period of IFR to LIFR ceilings through late morning.
Ceilings begin to improve as the stratus begins to lift Monday
after noon. Southeasterly winds will be lightly breezy with
gusts of 15-20 kts for areas along and east of I-29. These taper
off briefly in the morning and become westerly by the late
afternoon. Winds east of I- 29 once again increase in the
afternoon, gusting 15-20 kts. For areas along and east of the
Buffalo Ridge gusts to 25 kts are possible. In addition to the
wind shift will come a brief window of LLWS, mostly impacting
KHON and KSUX.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&
$$
DISCUSSION...Dux
AVIATION...AJP
Office: UNR
FXUS63 KUNR 080444
AFDUNR
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
944 PM MST Sun Dec 7 2025
.KEY MESSAGES...
- Drying out today and tomorrow
- Turning breezy Monday. A High Wind Watch has been issued for
Tuesday. Wind gusts up to 65 mph expected
- Turning colder and unsettled from Wednesday through the end of
week. Periods of light snow likely
&&
.DISCUSSION...(This Evening Through Sunday)
Issued at 1241 PM MST Sun Dec 7 2025
Rest of today... After a cold and foggy morning, dry air has
advected into the region and has quickly eroded the low clouds
and fog allowing for ample sunshine to begin climbing this
afternoon. Expect mostly clear skies to prevail for the rest of
the day. Dry conditions will continue into Monday with breezy
conditions developing during the afternoons. These winds may
approach advisory level criteria at times, but not expecting to
issue any highlights given the High Wind Watch is currently in
affect for the stronger event on Tuesday.
Confidence has increased enough that a High Wind Watch has been
issued for much of western SD and the central SD Plains. Minor
changes with the evolution of the deepening low pressure system
progged to move SE across the northern Plains on Tuesday. Latest
models now have this low getting caught up with another area of
low pressure across the north central portions of Canada and
developing a double barrel low pattern, with the southern closed
low being what impacts western SD. This has elongated the belt of
850mb winds and has slowed down the speed of this system. This
means that while the 850mb winds have decreased slightly, the
duration of the winds across the area has increased. Event with
the slight weakening of the winds models still depict winds around
50 knots right off the surface and with strong CAA still expected
in rapidly increasing heights, we are still expecting the
development of widespread wind gusts exceeding 58 mph, thus the
High Wind Watch has been issued for Tuesday afternoon through
Tuesday evening.
Wednesday through the rest of week, models begin to diverge
regarding the overall pattern setup across the region. While both
solutions favor keeping daily chances for precipitation across the
area, how impactful and how much snow will fall remains the big
question going forward.
&&
.AVIATION...(For the 06Z TAFS Through 06Z Monday Night)
Issued At 944 PM MST Sun Dec 7 2025
VFR conditions expected through the forecast period.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...High Wind Watch from Tuesday morning through Tuesday evening for
SDZ001-002-012>014-025-026-030>032-042-043-046-049-072>074-
077-078.
WY...None.
&&
$$
DISCUSSION/KEY MESSAGES...Woodward
AVIATION...Wong
Office: ABR
FXUS63 KABR 080514 AAB
AFDABR
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1114 PM CST Sun Dec 7 2025
.KEY MESSAGES...
- Light snow moves from the James valley to the Sisseton Hills
region this afternoon/evening. Inch or less type snowfalls today.
- Potential for Sisseton hills downslope winds (30 to 40 mph) with
blowing snow issues Monday afternoon.
- Next clipper will most likely (60-80% chance of occurrence) be
preceded by a brief period of light freezing rain Tuesday morning
before temperatures thaw 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.
- Some of the coldest air of this winter season could be settling
over the area by the end of the week, including high temperatures
around or slightly above 0F and low temperatures down into the
single digits below to teens below zero and wind chill values Friday
morning as low as -20F to -35F.
&&
.UPDATE...
Issued at 516 PM CST Sun Dec 7 2025
Added pops west to the Missouri river to account for ongoing snow
that the radar is overshooting.
&&
.DISCUSSION...
Issued at 247 PM CST Sun Dec 7 2025
North to south band of snow continues to migrate east and is just
now into Aberdeen. Some light snow continues within the stratus to
the west below the radar beam as well. Accumulations on webcams
appear to be light, and there has also been some blowing/drifting
noted with winds west of here in the 15 to 25 mph range. Still
sticking with the "around an inch" messaging with this feature.
As we go through Monday, southerly flow develops out ahead of a weak
surface low that moves through North Dakota. A weak gradient for us
will limit the ability to mix out the coldest air in the northeast
until late, when the low moves into the Red River valley. It should
be noted that while flow is mostly unidirectional aloft, there is a
weak signal for Sisseton hills downslope winds across the northeast
in the afternoon. Despite warming temperatures, there is quite a bit
of blowable light/fresh snow up in the northeast, so bumped up the
wording for blowing snow in the downslope area as BUFKIT shows about
35kts in the critical layer.
The weak clipper moves on, with a weak ridge in place Monday
night/Tuesday morning ahead of a stronger clipper system building in
Alberta/Saskatchewan. Between 12Z and 00Z it will have zipped from
Canada into the far northeast of South Dakota with a surface
pressure of between 992 and 985mb. Each deterministic model has come
up with a slight variation with this central pressure over the last
few runs, and also with slight variations in placement/track. This
plays into confidence in regards to wrap around precipitation (that
we will address later).
Firstly, out ahead of this system there is already warm air in
place, having previously arrived with the first system and left over
from Monday. 21Z Tuesday, 850mb temperatures are mostly in positive
territory, though models vary on the strength of the warm air.
Generally speaking, its about a standard deviation above climo.
BUFKIT profiles suggest there may be enough of a shallow cold layer
below the warm nose to present a freezing rain threat with any
moisture across the northeast. How much rainfall? NBM 25th/75th
range is a tenth to a quarter inch, with a mean of about a tenth or
two meaning a large range for just a light amount of moisture.
Almost 20 percent of ensemble members fail to generate QPF for
Sisseton for that matter. And with warm advection and a shift to
westerly flow enhancing mixing, temperatures will continue warm as
perception is ongoing. Thus, while freezing rain is a real threat,
the duration is limited to mainly during the onset of rainfall with
a thaw through the day.
Moisture falling on snowpack and the warming temperatures (on top of
what may have been experienced Monday) will severely limit the
blowability of any snow on the ground moving forward.
With the onset of cold advection, winds will see a substantial
upward trend. A 20 to 24mb gradient, with pressure rises of
upwards of 16mb/6 hours will likewise enhance winds. GEFS 850mb
winds are 3 standard deviations above climo, and EC EFI/shift of
tails continues to highlight South Dakota for potential high
winds. As such, issued a high wind watch for most likely areas
impacted by high winds. East of this headline, additional
headlines will need to be evaluated. Will it require a wind
headline or some sort of winter weather related headline with wrap
around moisture possibly moving into the CWA? BUFKIT profiles
aren't overly supportive for snow (lack of ice in the dendritic
growth zone) in the wrap around Tuesday night. Deterministic NBM
is only a few hundredths of QPF. There is still time between now
and when this system gets going so any slight southward shift in
the track would result in high potential for snow falling in a
core of 40 to 50 mph winds across the northeast.
That cold air that follows for late in the work week. 850mb
temperatures are a standard deviation below climo. While much of the
snowpack will have been modified at this point, there may be another
round of light snow on Thursday/Friday.
&&
.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1112 PM CST Sun Dec 7 2025
Terminals KABR,KATY,KPIR,KMBG
IFR stratus will prevail tonight with improvement expected between
15z and 18z Monday. Westerly winds increase in the afternoon with
gusts to 25 kts.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...High Wind Watch from Tuesday afternoon through late Tuesday
night for SDZ003>005-009-010-015>017-033>037-045-048-051.
MN...None.
&&
$$
UPDATE...20
DISCUSSION...07
AVIATION...20
