sd discuss
Office: FSD
FXUS63 KFSD 071405
AFDFSD
Area Forecast Discussion
National Weather Service Sioux Falls SD
805 AM CST Sun Dec 7 2025
.KEY MESSAGES...
- Winds chills as cold as -20 degrees will continue through
mid-morning mainly across southwestern MN.
- Additional chances for light snow are expected this afternoon
and evening with accumulations of an inch or less expected.
- A parade of waves will move through the region during the
week ahead, bringing snow risks on both Tuesday and Thursday.
The most impactful snow system to watch may be on Thursday.
- Confidence is growing that winds Tuesday night into Wednesday
may break or exceed the 40 mph mark. We'll need to monitor the
snow pack and air temps closely to monitor blowing snow
potential.
&&
.UPDATE...
Issued at 801 AM CST Sun Dec 7 2025
Shortwave trough quickly moving through western South/North
Dakota this morning producing a corridor of light to
occasionally moderate snow that's moving eastward. Model
agreement in this wave and precipitation holding together as it
moves east has boosted confidence that light snow accumulations
will be likely later Sunday into Sunday night. Therefore have
pushed PoPs upwards over most areas for the eastward moving
band. A slight upward tick in QPF will result in snow totals
around one half inch in most areas. However, areas of the
Buffalo Ridge where dPVA is strongest and southwesterly warm
advection lingers longer could see 1-1.5" of snow by midnight.
&&
.DISCUSSION...
Issued at 342 AM CST Sun Dec 7 2025
TODAY & TONIGHT: Another cold day ahead! Taking a look across the
area, any lingering flurries continue to gradually dissipate this
morning as a surface high approaches from the northwest. From here,
a cold start to the morning is expected as a fresh snowpack and
lingering cold air advection (CAA) help most areas start on either
side of zero temperature-wise. Combine this with marginally breezy
northeasterly winds and the setup is primed for even colder winds
through mid-morning with values as low as 20 degrees below zero.
While this will mostly affect southwestern MN, make sure to bundle
up if you have any morning activities. Otherwise, quieter conditions
will persist for the first half of the day as temperatures peak in
the positive single digits to low 20s. Looking aloft, a quick mid-
level wave will closely follow the departing surface high leading to
additional chances for light snow during the afternoon to evening
hours. However, unlike with our previous system; amounts will likely
be on the lighter side with additional accumulations of 1 inch or
less expected. Lastly, as temperatures fall into the single digits
to teens overnight; could see the return of below zero wind chills
in southwestern MN to start the day on Monday.
MONDAY-WEDNESDAY: Looking into the new week, quieter conditions
temporarily return by Monday as northwesterly flow continues aloft.
With the return of southerly surface winds and increasing mid-level
warm air advection (WAA), temperatures will rebound towards the 30s
to low 40s for the day with the warmest conditions across southcentral
SD. Looking aloft, the wave train will continue across the northern
plains as northwesterly flow ushers in multiple waves through Wednesday.
The first clipper wave will dives across parts of northern MN by Monday
afternoon passing just north of us. A second and more robust clipper
wave will dive across portion eastern ND and central MN by Tuesday.
While most of the better dynamics will likely stay north of us, areas
north of I-90 will likely get enough lift from the base of the trough
to get increased precipitation chances (30%-50%). However, with
temperatures trending more mild with highs in the upper 30s to
low 50s for the day; most of this should fall as rain.
Nonetheless, can't rule out an eventual transition to light snow on
the backside of the system as temperatures fall overnight. One thing
worth noting is the tightening SPG with the clipper will likely lead
to strong winds with gusts of 40+ mph from Tuesday night into
Wednesday. Depending on how the previous systems have affected our
snowpack, we could see areas of blowing/drifting snow develop
through Wednesday morning. Nonetheless, this will be something
to watch moving forward. From here, a third mid-level wave will
swing through by Wednesday morning along with its associated
cold front. While there won't likely be much precipitation
associated with this system, the strong blast of arctic air will
decrease our temperatures going forward with highs mainly in
the teens to 20s for most areas. Lastly, while some key details
are uncertain; mid-range guidance is starting to pick up on the
potential for additional snow from Wednesday night into Thursday
as another quick clipper swings through the area. With this in
mind, make sure to monitor your local forecast as this would the
period to monitor the most.
THURSDAY ONWARDS: Heading into the extended period, its more rinse
and repeat. Periods of snow will continue for most of the day on
Thursday before tapering off. A surface high moves through the area
by Friday to replace the previously mentioned system. By Saturday
and Sunday another approaching clipper brings the potential for more
snow across the area. Lastly, temperatures will hover near to just
below normal with the coldest conditions expected on Friday and
Saturday as highs peaking the single digits to mid teens.
&&
.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 540 AM CST Sun Dec 7 2025
A mix of conditions this morning will give way to mostly MVFR to
IFR this TAF period. Taking a look at satellite imagery, most
areas continue to be locked into stratus this morning with no
relief in site. Expect the stratus to hang around for most of
the day as our next system approaches bringing some light snow
to the area. Otherwise, light northeasterly winds this morning
will become more southeasterly by this evening. Lastly, while
confidence is low; some high resolution guidance is picking up
on some patchy fog development Monday morning. We'll have to
continue to monitor that moving forward.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&
$$
UPDATE...Dux
DISCUSSION...05
AVIATION...05
Office: UNR
FXUS63 KUNR 071127
AFDUNR
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
427 AM MST Sun Dec 7 2025
.KEY MESSAGES...
- Light snow this morning with minor accumulations
- Strong winds possible on Tuesday, with gusts over 60 mph
- Unsettled and colder for the second half of the week; snow
amounts uncertain
&&
.DISCUSSION...(Today Through Saturday)
Issued at 323 AM MST Sun Dec 7 2025
Northwest flow continues aloft across the western to central CONUS.
The next wave is crossing MT/WY at this time, with upper level
forcing ahead of the wave, along with a strong surface trough/warm
front. KUDX radar shows snow showers moving across NE WY and far
western SD, along the state line. Behind the trough over the NE WY
plains, temps are in the upper 20s to mid 30s...and over western SD
in the teens. This band of snow will continue eastward this morning,
crossing the western SD plains before moving into central SD by late
morning. Accumulations will be light. Lingering snow showers are
possible across the northern/western Black Hills where upslope
enhancement and steep lapse rates will persist until drier air moves
in around midday. Highs will generally be in the 30s to mid 40s.
Warmer air will continue to advect in overnight tonight, as highs
reach the 40s to lower 50s. A trough crossing the area Monday will
support windy conditions, with gusts to 35 to 45mph. The next wave
affect the region on Tuesday. The extensive warm airmass in place
across the northern plains will support highs in the upper 40s to
lower 60s. A strong upper wave/surface low will cross the Dakotas
bringing strong NW winds. Guidance over the last 24 hours has
trended slightly northward with the track of the system, which has
slightly weakened forecast winds for the CWA. However, it still
looks like High Wind Warning criteria gusts may still affect the
region. Still, am curious how the solutions will change with the 12z
run and if wind speeds will continue to decrease. Will keep on eye
on the trend for potential issuance of headlines. Unsettled weather
is still on tap for the second half of the week into the weekend.
While it does look like the area will see snow, solutions vary
widely, ranging from light to heavy amounts. There is agreement that
much colder air will push into the region toward the end of the
week.
&&
.AVIATION...(For the 12Z TAFS Through 12Z Monday Morning)
Issued At 427 AM MST Sun Dec 7 2025
MVFR/IFR conditions will continue, especially along a line of snow
showers now crossing western South Dakota. Behind the band of
snow, conditions will improve to VFR and remain for the rest of
the forecast period.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&
$$
DISCUSSION/KEY MESSAGES...13
AVIATION...13
Office: ABR
FXUS63 KABR 071113
AFDABR
Area Forecast Discussion
National Weather Service Aberdeen SD
513 AM CST Sun Dec 7 2025
.KEY MESSAGES...
- A band of light snow moves west to east today. Less than an inch
of accumulation is expected with this system.
- Northwest winds Tuesday afternoon into late Tuesday evening could
gust in excess of 55 mph.
- 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 512 AM CST Sun Dec 7 2025
Aviation discussion below has been updated in accordance with the
12Z TAF issuance.
&&
.SHORT TERM /TODAY THROUGH MONDAY AFTERNOON/...
Issued at 306 AM CST Sun Dec 7 2025
Only a short break in precipitation is expected as the next round
moves in central and north central South Dakota beginning this
morning. This precip will be supported by a jet streak aloft, which
will traverse eastward through the day this afternoon and evening,
bringing the precip with it. Snow is expected to be the main
precipitation type through the event, but there is minor potential
for a transition to freezing rain this evening. This would occur due
to the upper-levels de-saturating, potentially to the point at which
temperatures in the saturated layer could be warm enough to support
liquid accumulation aloft. Luckily model guidance shows this would
be on the very back end of the system as precip is moving out,
meaning that the greatest source of lift will be out of the area and
precip rates would be lower. With this being such a marginal
possibility, no significant freezing rain potential has been added
to the gridded forecast, but also would not be surprised to see it
if all the variables come together perfectly. Precipitation is
expected to exit northeastern South Dakota around midnight tonight
at the latest.
In total with this system, only a few hundredths of liquid
equivalent are expected, translating to less than an inch of snow
across the area. Looking at the latest NBM 90th percentile as a
reasonable "worst case" value, QPF values sit around a tenth of an
inch. This would translate to between 1"-2" in accumulation. It is
worth noting that under a similar pattern yesterday, snow ratios
were quite high, so it is possible that we once again will
overachieve and come closer to that 90th percentile snowfall.
Monday offers a bit of a reprieve from the snow, and conditions are
expected to be dry through the day. Another shortwave supporting a
low pressure center will come off the upper-level ridge, but this
time it will stay to the north of the Aberdeen CWA. The track of the
low will allow temperatures to warm up a bit, particularly over
central South Dakota. Highs tomorrow are expected to reach the 40s
in that area (about 10 degrees above normal for mid-December), with
highs decreasing down to the low-30s as you move into northeastern
South Dakota. Areas west of the James River are expected to see
highs above freezing, so partial to full melting of the snowpack
will likely occur.
&&
.LONG TERM /MONDAY EVENING THROUGH SATURDAY/...
Issued at 306 AM CST Sun Dec 7 2025
When the period opens Monday night, in the middle of a low level WAA
event. Much above normal temperatures are expected to persist into
Tuesday, with precipitation developing/working west to east across
the CWA, particularly north of U.S. Highway 212. Surface
temperatures may be at or below freezing to start Tuesday morning,
but within a few hours of sun-rise Tuesday, surface temperatures on
an efficient westerly mixing layer wind should be warming things up
to above freezing while precipitation potential persists. So, the
forecast contains a few hours of freezing rain mention before
transitioning to rain potential for the rest of the day.
The clipper system bringing the warm air and precipitation chances
on Tuesday will sweep a strong cold frontal passage through the CWA
Tuesday afternoon through late Tuesday evening. The combination of
already quite strong winds at 0.5km with strong low level CAA and a
strong pressure rise/tendency heading into early Tuesday evening
supports the potential for headlineable winds. Still too soon to
issue a wind headline for Tuesday afternoon/night. But, it is being
monitored closely. Not for a blowing snow concern, given all the
melting and rain that will have fallen during the day on Tuesday,
crusting any remaining snowcover. But, strength of winds may make
for rather hazardous traveling conditions. If there is any post cold
frontal falling snow to be had across northeast South Dakota Tuesday
night, that area could actually see some blowing snow/reduced
visibility late Tuesday night into early Wednesday morning.
Still more chances for precipitation showing up, potentially
Wednesday night into Thursday morning and again by Saturday. Staring
to approach 2 standard deviations below normal for 850hpa
standardized temperature anomalies in the ENS S.A. data table for
Friday. Ensemble-powered forecast low temperatures Thursday night
are below zero (0F to ~ -12F) and high temperatures Friday range
from ~ -3F to 12F, with Friday night lows dipping down below zero (~
-2F to -15F) again. Wind chill values are forecast to fall to
between -20F to -35F heading into Friday morning while winds are
forecast to be 10 to 20 mph sustained with gusts up to 30 mph
possible. Simply brutal conditions, that are being monitored for a
potential "cold weather" headline.
&&
.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 512 AM CST Sun Dec 7 2025
Terminals KABR,KATY,KPIR,KMBG
Another round of snow will move into central and north central South
Dakota this morning, expanding east through the day today. Snowfall
rates are expected to remain fairly low, but will still be enough to
reduce visibility at times. Generally MVFR visibilities can be
expected where snow is present, with an occasional dip down to IFR
visibilities. The same can be said for ceilings, as the main cloud
deck will be MVFR with occasional IFR conditions. Snowfall will move
out of central/north central South Dakota by this evening and out of
northeastern South Dakota tonight. There is some potential for
lingering light snow on the back end of the system, so have left a
PROB30 group in the TAFs for the ending of the precipitation. MVFR
ceilings will also linger on the back end of the system, moving out
from west to east near the end of the TAF period Monday morning.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...BC
SHORT TERM...BC
LONG TERM...10
AVIATION...BC
