sd discuss
Office: FSD
FXUS63 KFSD 050958
AFDFSD
Area Forecast Discussion
National Weather Service Sioux Falls SD
358 AM CST Fri Dec 5 2025
.KEY MESSAGES...
- Wintry mix continues to transition to light snow this morning
mainly along and north of I-90. While mostly light accumulations
are expected, a few patchy slick spots will be possible
especially on untreated surfaces.
- A quick-moving winter system will bring periods of light to
moderate snow to most areas between Saturday and Saturday
night. With between 2-5 inches of additional snowfall expected
and pockets of locally higher possible, confidence is high
(80+%) in minor to moderate travel impacts especially along
and east of I-29.
- Near to below normal temperatures will continue into the new
week with the next chances for precipitation possible on
Tuesday.
&&
.DISCUSSION...
Issued at 356 AM CST Fri Dec 5 2025
TODAY & TONIGHT: A slightly less cold day ahead! Taking a look
across the area, we're continuing to see a wintry mix of freezing
rain and/or sleet transition to light snow this morning mainly
across the highway-14 corridor via web-cameras. While mostly light
accumulations are expected, can't rule out a few slick spots across
the previously mentioned areas this morning especially on untreated
surfaces. With this mind, make sure to drive with care while making
those morning commutes. From here, should see most of this wintry
precipitation continue to gradually spread to the southeast with the
cold front for most of the day before things taper off this evening.
Otherwise, we'll be less cold today with highs in the low to upper
30s. However, with increasing westerly to northwesterly winds;
conditions will still be on the chillier side so make sure to have
those coats handy. Lastly, cooler air will continue to funnel in
overnight leading to lows in the single digits to 20s with the
coldest conditions across southwestern MN. With this the stage is
set for our next winter system
SATURDAY AND SUNDAY: Looking into the rest of the weekend, an active
pattern will continue aloft as a quick moving system ejecting out of
the Rockies into the northern and central plains by Saturday.
Starting in the morning, most of the CAMs have light snow developing
in the western portion of SoDak in the WAA regime ahead of the
surface trough. As the surface trough tracks to the east-southeast
into our area by late morning, most guidance continue to show an
enhanced area of snowfall developing across southeastern SD which
will be the primary driver of our accumulations with this system.
Underneath this developing band of snow, increasing snowfall rates
of 1" to 1.5" in/hr according to the HREF could lead to moderate to
heavy accumulations at times in the afternoon to early evening
timeframe. Nonetheless, should see things taper off by late evening
as everything progresses southeastwards into central IA.
Shifting over to overall amounts, most areas can expect between 2-5
inches of fluffy snow along and east of the James River with the
highest amounts east of Highway-81. While isolated pockets of higher
(6+") will be possible, deterministic guidance continues to struggle
with where the the band exactly sets up. Nonetheless, portions of
far southeastern SD and northwestern IA continue to look like the
favorites at the moment. With all this in mind and collaboration
with our neighbors, decided to pull the trigger on a Winter Weather
Advisory for most areas besides portions of southcentral SD
(Gregory, Brule, and Charles Mix Co.) start at 6 am on Saturday.
Lastly, minor to moderate travel impacts are expected across the
area mostly due to falling snow and accumulative amounts so make
sure to make adjustments to travel plans accordingly. Shifting gears
to Sunday, increases to our existing overall snowpack and northerly
surface winds will lead to more blustery conditions with highs
mainly in the single digits to upper teens. Colder conditions
overnight will lead to even colder wind chill Sunday night into
Monday morning with values as cold as 14 below possible.
NEXT WEEK: Looking into the new week, an active pattern persists
aloft as northwesterly flow continues to usher in the wave train.
The better of the chances continues to look like Tuesday night into
Wednesday. However, with guidance diverging in terms of the track of
the system uncertainty remain in overall amounts. With a stronger
push of WAA expected ahead of this system, we'll likely have to
monitor p-types too. Otherwise, near to just below seasonal
temperatures will continue across the area.
&&
.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1046 PM CST Thu Dec 4 2025
VFR conditions begin the TAF period. VFR stratus is currently
overspreading the area. This will set the stage for mixed
precipitation to return tonight. Any mixed precipitation that does
fall will reside largely along and north of I-90. Ceilings will drop
to MVFR levels in falling precipitation and further down to IFR/LIFR
levels. Visibilities will remain at MVFR thresholds in falling
precipitation. Chance for mixed precipitation will persist through
the morning hours tomorrow before dry conditions return for the
afternoon timeframe. However, ceilings will remain at LIFR/IFR/MVFR
levels through the afternoon and into the evening timeframe. Winds
will turn to out of the northwest by tomorrow afternoon with gusts
up to 15 to 30 knots before weakening heading into the evening.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...Winter Weather Advisory from 6 AM to 6 PM CST Saturday for
SDZ038>040-052>056-058>062-064>071.
MN...Winter Weather Advisory from noon to 9 PM CST Saturday for
MNZ071-072-080-081-089-090-097-098.
IA...Winter Weather Advisory from noon to 9 PM CST Saturday for
IAZ001>003-012>014-020>022-031-032.
NE...Winter Weather Advisory from 6 AM to 6 PM CST Saturday for
NEZ013-014.
&&
$$
DISCUSSION...05
AVIATION...Meyers
Office: UNR
FXUS63 KUNR 050940
AFDUNR
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
240 AM MST Fri Dec 5 2025
.KEY MESSAGES...
- Light snow returns tonight into Friday, then another chance on
Saturday and Sunday.
- Warmer and breezy conditions early next week.
- Unsettled weather may return for the middle of next week.
&&
.DISCUSSION...(Today Through Thursday)
Issued at 238 AM MST Fri Dec 5 2025
Upper air analysis shows northwest flow continuing from the Pac NW
all the way to the Upper Midwest, with a series of embedded waves.
The next disturbance to affect the area is crossing central/eastern
MT ATTM. Surface analysis shows a broad trough extending from the
Dakotas into central Canada, supporting W/NW winds of 10-20kt...and
gusts up to 30kt over the NW SD plains. KUDX radar shows light snow
moving into portions of NE WY and the northern Black Hills, which is
expected to bring an inch or two of snow by 12-14z this morning. The
wave will cross the area mid-morning...behind it weak mid-level
subsidence to the CWA, ending the best chance for accumulating
snowfall. However, steep low level lapse rates will persist through
the day, allowing for continued low clouds and flurries/light snow.
Any accumulations that does occur for the remainder of the day will
be less than an inch. Surface high pressure will move into the
Dakotas tonight, bringing a brief dry period before the next round
of unsettled weather moves in on Saturday. A surface low will
develop ahead of the next wave, along a stalled weak baroclinic
zone. Isentropic forcing will increase ahead of the low over south
central SD, then quickly move southeast of the CWA. Northerly flow
behind the low will reinforce the colder air and will be the focus
for precip Saturday and Saturday night. Snow is expected across much
of western SD and the northern Black Hills...with southwest SD as
the only exception. The highest snow amounts will be over NW SD (1-
3") and the northern Black Hills (1-4"). Lingering snow will be
possible on Sunday, especially as models suggest another wave
pushing through. Snow amounts will be minimal. Low amplitude dirty
ridge then builds over the western CONUS, supporting strong warm air
advection. In addition to dry weather, temps should reach into the
40s/low 50s on Monday...then about 5 degrees warmer on Tuesday,
along with breezy conditions. Unsettled weather could return toward
the middle of next week, but there remains much uncertainty at this
time.
&&
.AVIATION...(For the 06Z TAFS Through 06Z Friday Night)
Issued At 946 PM MST Thu Dec 4 2025
MVFR/IFR conditions and areas of -SN will develop across
northeastern WY into northwestern SD and the northern Black Hills
through early this morning. Conditions should improve through the
day, though MVFR conditions may linger across northwestern SD
through late in the TAF period. Northwest winds will also pick up
through the overnight hours into the morning especially across
northwestern SD where gusts of up to 37 kt are possible.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&
$$
DISCUSSION/KEY MESSAGES...13
AVIATION...Wong
FXUS63 KUNR 050941
AFDUNR
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
240 AM MST Fri Dec 5 2025
.KEY MESSAGES...
- Light snow today, then another chance on Saturday and Sunday.
- Warmer and breezy conditions early next week.
- Unsettled weather may return for the middle of next week.
&&
.DISCUSSION...(Today Through Thursday)
Issued at 238 AM MST Fri Dec 5 2025
Upper air analysis shows northwest flow continuing from the Pac NW
all the way to the Upper Midwest, with a series of embedded waves.
The next disturbance to affect the area is crossing central/eastern
MT ATTM. Surface analysis shows a broad trough extending from the
Dakotas into central Canada, supporting W/NW winds of 10-20kt...and
gusts up to 30kt over the NW SD plains. KUDX radar shows light snow
moving into portions of NE WY and the northern Black Hills, which is
expected to bring an inch or two of snow by 12-14z this morning. The
wave will cross the area mid-morning...behind it weak mid-level
subsidence to the CWA, ending the best chance for accumulating
snowfall. However, steep low level lapse rates will persist through
the day, allowing for continued low clouds and flurries/light snow.
Any accumulations that does occur for the remainder of the day will
be less than an inch. Surface high pressure will move into the
Dakotas tonight, bringing a brief dry period before the next round
of unsettled weather moves in on Saturday. A surface low will
develop ahead of the next wave, along a stalled weak baroclinic
zone. Isentropic forcing will increase ahead of the low over south
central SD, then quickly move southeast of the CWA. Northerly flow
behind the low will reinforce the colder air and will be the focus
for precip Saturday and Saturday night. Snow is expected across much
of western SD and the northern Black Hills...with southwest SD as
the only exception. The highest snow amounts will be over NW SD (1-
3") and the northern Black Hills (1-4"). Lingering snow will be
possible on Sunday, especially as models suggest another wave
pushing through. Snow amounts will be minimal. Low amplitude dirty
ridge then builds over the western CONUS, supporting strong warm air
advection. In addition to dry weather, temps should reach into the
40s/low 50s on Monday...then about 5 degrees warmer on Tuesday,
along with breezy conditions. Unsettled weather could return toward
the middle of next week, but there remains much uncertainty at this
time.
&&
.AVIATION...(For the 06Z TAFS Through 06Z Friday Night)
Issued At 946 PM MST Thu Dec 4 2025
MVFR/IFR conditions and areas of -SN will develop across
northeastern WY into northwestern SD and the northern Black Hills
through early this morning. Conditions should improve through the
day, though MVFR conditions may linger across northwestern SD
through late in the TAF period. Northwest winds will also pick up
through the overnight hours into the morning especially across
northwestern SD where gusts of up to 37 kt are possible.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&
$$
DISCUSSION/KEY MESSAGES...13
AVIATION...Wong
Office: ABR
FXUS63 KABR 050914
AFDABR
Area Forecast Discussion
National Weather Service Aberdeen SD
314 AM CST Fri Dec 5 2025
.KEY MESSAGES...
- Precipitation lingers this morning, with a wintry mix of snow,
rain, and freezing rain possible. Precipitation rates will be light,
and less than half an inch of additional snowfall accumulation is
expected.
- Snow returns Saturday as a clipper system moves through. 1"-3" of
accumulation will be possible east of the Missouri River through
Saturday evening, with up to 2" possible along and west of the
Missouri River.
- There will be periodic lower chances for precipitation (20-40%)
through early next week, as more weak weather systems have the
potential to move through the region.
- Strong northwest winds of 20 to 35 mph with gusts in excess of 45
mph are a concern from late Tuesday afternoon through Wednesday
morning.
&&
.SHORT TERM /TODAY THROUGH SATURDAY AFTERNOON/...
Issued at 242 AM CST Fri Dec 5 2025
Currently (~08Z) watching light precipitation traverse across the
Aberdeen forecast area. Surface observations of both snow and rain
have been reported this evening, with the rain mainly due to some
areas staying above freezing to this point. Overnight lows across
the area are expected to be near to just below freezing, so it is
possible that if temperatures overachieve this morning some areas
could see light rain over light snow through the night. Ice
production is generally expected aloft, which is supported by radar
observations showing no signs of a melting layer present. With
surface temperatures dropping near freezing. it will also be
possible to see pockets of freezing rain this morning. Regardless of
what precip type is falling, rates will continue to be light and
accumulation of a few hundredths of liquid equivalent (less than
half an inch of snow) is expected. Precipitation will linger through
late morning into the early afternoon at the latest, giving way to
dry conditions and weakening winds overnight tonight.
The next clipper system moves through on Saturday, supporting snow
across the forecast area. The low pressure center is expected to
track over the WY/SD/NE state borders Saturday morning continuing
southeasterly through the afternoon, putting the Aberdeen CWA on the
northeastern side of the low. There is some slight disagreement in
model soundings when looking at where the lift will be in relation
to the DGZ. The current expectation is for SLRs to sit somewhere
within the 10-15:1 range, although parts of central South Dakota
could fall lower depending on the exact track of the low and how far
north warmer air is able to penetrate (which would remove some of
the snow growth out of the DGZ the more warm air pushes north).
Ultimately regardless of snow ratio, ensemble mean QPF through
Saturday evening is around 0.05"-0.10" over central and north
central South Dakota, increasing to around 0.10"-0.20" moving into
eastern South Dakota. This translates to an expectation of around 1"-
2" across most of the CWA, with some higher totals over the east. It
is worth noting that this is a slight increase from the past
forecast cycle, particularly over eastern South Dakota. Looking at
90th percentile values in the NBM as a proxy for a reasonable "worst-
case scenario", snowfall values in the east remain at 4" or below
for the duration of the event. With all that in mind, there are no
plans to issue any headlines for this event at this time.
Wind may also cause some minor issues with this snowfall in the form
of drifting snow. As snow is falling over central South Dakota,
northeasterly winds around 15-20 miles per hour will be present,
with gusts up to 25-30 miles per hour. With snowfall rates expected
to be fairly low and wind speeds falling somewhat short of a typical
Blowing Snow event, widespread impacts are not anticipated. However
the wind and fresh snowpack will likely be enough to cause some
isolated drifting snow. While not high-impact, drifting snow may
make driving a bit more dangerous at times.
&&
.LONG TERM /SATURDAY EVENING THROUGH THURSDAY/...
Issued at 242 AM CST Fri Dec 5 2025
From Saturday evening through the end of the period, the over-
arching flow pattern theme remains "positive PNA". Northwest flow is
still lining up transient clipper-like shortwaves over the region,
each one separated from the next by roughly 24 hours.
With the active pattern of low pressure systems working through, the
low level thermal advection pattern will be pretty busy. Weak low
level CAA is happening Saturday night into Sunday morning, but low
level WAA is expected to kick in by late in the day Sunday and
persist into Monday. Warm air is forecast to stick around Monday
night into Tuesday before the next system's strong cold frontal
passage knocks temperatures back down to near to below normal for
the middle of next week.
The probabilities of seeing a 0.10in or more of water equivalent in
any given 24 hour period in the out periods is low (less than 10
percent). Likewise, the chances of seeing 0.01in or more of freezing
rain/ice accumulation or 3 inches or more of snow are low. That
being said, the clipper system moving through North Dakota into
Minnesota Tuesday/Wednesday will need to be watched closely for any
shifts further south in track/placement, as this system holds the
chance of producing headline-able conditions. But for now, model
output/ensembles are still maintaining that the bulk of this system
will track through the region north of this CWA.
Looking a little bit more closely at the wind potential
Tuesday/Wednesday, it appears that a corridor of fairly strong winds
(off the surface) will be overspreading the CWA while it's within
the warm sector of the clipper system. Current model progs suggest
that it's not until at or after 21Z Tuesday that strong winds aloft
will be able to be mixed down to the ground, as that is roughly what
time the system's cold frontal passage is slated to begin sweeping
through the CWA, first across north central South Dakota, but then
quickly following through central and northeast South Dakota and
west central Minnesota, especially at or after 00Z Wednesday when
strong low level CAA, pressure rises and winds just a half kilometer
off the ground will be working in tandem to present a strong wind
concern. Not too confident about a blowing snow concern, though, if
the CWA has been at or above the freezing mark for nearly 48 hours.
Thinking there may not be much blowable snow left after warm
boundary layer conditions like that.
&&
.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1145 PM CST Thu Dec 4 2025
Terminals KABR,KATY,KPIR,KMBG
A light wintry mix of rain and snow over mainly north central SD
(MBG) will change over to snow shortly after 06Z. There is some
concern of light freezing drizzle or freezing rain along with the
light snow at ABR until 10Z. Most of the precipitation will stay
north or in the form of light rain at PIR. Along with varying
precipitation types, IFR ceilings are expected at all sites but
PIR which should stay VFR to MVFR through the forecast period.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
SHORT TERM...BC
LONG TERM...10
AVIATION...06
