sd discuss
Office: FSD
FXUS63 KFSD 041132
AFDFSD
Area Forecast Discussion
National Weather Service Sioux Falls SD
532 AM CST Thu Dec 4 2025
.KEY MESSAGES...
- A very cold morning with wind chills as cold as -25 east of
the James River and to -15 west of the James River.
- Wind gusts nearing 40 mph this afternoon over southwest
Minnesota and nearby parts of eastern South Dakota and
northwest Iowa will lead to patchy blowing snow. Please use
extra caution on the roads.
- Light precipitation is expected late tonight into Friday
evening with minor accumulations. A mix of precipitation could
lead to minor accumulations.
- Confidence is increasing in the potential for accumulating
snowfall Saturday into Saturday night, as models come into
more agreement. Chances for at least an inch of snow are high
(over 70%). Guidance still varies on where the heaviest
snowfall may fall. If you have travel plans, keep an eye on
the forecast.
- Cold, below normal temperatures are expected to continue
through the weekend, with signs of temperatures moderating
closer to normal next week.
&&
.DISCUSSION...
Issued at 301 AM CST Thu Dec 4 2025
TODAY: Surface high slides east through this morning. Guidance
continues to handle stratus poorly west of the James River, which
has been moderating temperatures somewhat in this area. 2 AM
temperatures are below zero for most, with wind chills in the teens
to mid 20s below. Still may see some locations east of I-29 briefly
drop below Cold Weather Advisory criteria, but have remained
headline free given marginal and brief conditions. We should warm
into the teens (east) to mid 30s (south central SD).
WAA increases today, and we'll see a tightening surface pressure
gradient as well as increased mixing. This allows for a breezier
day, with southerly winds gusting around 35 to 40 mph - strongest in
our higher elevations of the Buffalo Ridge. Main concern with these
stronger wind gusts will be the potential for blowing snow. Blowing
snow could lead to locally reduced visibility and patchy slick spots
so be prepared for changing conditions this afternoon and evening.
TONIGHT-FRIDAY: Raised pops and QPF from the NBM with guidance
coming into better agreement with light precipitation thanks to a
stronger mid level wave and a surface boundary moving through the
area after midnight and into Friday. However, there are still some
questions regarding how much we'll saturate the column and in the
DGZ, so could see some light freezing rain or freezing drizzle.
Light precipitation looks to be largely be focused along and north
of I-90 into northwestern IA. Any accumulations through the day
Friday and into Friday night remain light, less than half an inch.
Lows tonight fall into the teens and 20s with highs Friday in the
30s.
SATURDAY-SATURDAY NIGHT: Models are coming into more agreement with
a stronger wave/trough swinging through the central Plains Saturday
into Saturday night. The 04.00 GFS/NAM remain the furthest south
with the precipitation, while the Canadian is further north and the
ECMWF is in the middle. Differences seem to largely be from where
the surface warm front and moisture advection end up. The increased
agreement is now reflected in the ensemble data as well, with a
significant increase in the chances for a tenth of an inch of
precipitation from 15-35% with the 03.00z runs to 55-85% with the
04.00z ensemble data. Similar increases can also be seen in the
potential for more than 0.25" during the same period. Again, there
are still varied in the location of the heaviest precipitation, but
certainly watch the forecast if you have travel plans. Chances for
an inch of snowfall are high (over 65%), and for 2" inches are
moderate to high (40-70%). Chances for greater than 4" of snow are
low (less than 30%). However, this may still change.
Much colder air returns Saturday night with lows below zero.
SUNDAY: Much colder air continues region Sunday with high pressure
returning. Highs may not exceed the single digits east of I-29, with
the teens elsewhere. Some guidance shows brief but light snow
Sunday, but confidence is low in this potential. Another cold night
Sunday night, in the single digits either side of zero.
MONDAY-MID WEEK: Northwesterly flow regime keeps a more active
pattern in place early to mid next week. Strongest wave is currently
progged to move through Tuesday night into Wednesday, which could
bring light precipitation back to the region. Details are uncertain.
Regardless, below to near average temperatures continue through mid
week.
&&
.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 525 AM CST Thu Dec 4 2025
An area of MVFR stratus continues to meander east toward the
I-29 corridor this morning. As has been recent trends, guidance
continues to handle this poorly. Have added MVFR mention to KFSD
and KSUX, although confidence is low in how long this will stick
around and how far east stratus extends.
Southerly winds increase today with gusts 20 to 30 knots, with
some gusts to 35 knots along the higher elevations of the
Buffalo Ridge, where blowing snow could lead to some reduced
visibility. May see some marginal LLWS, with the strongest part
of the LLJ over KSUX into northwestern IA this evening. Winds
taper down and shift to southwesterly late tonight into Friday
morning.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&
$$
DISCUSSION...SG
AVIATION...SG
Office: UNR
FXUS63 KUNR 041126
AFDUNR
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
426 AM MST Thu Dec 4 2025
.KEY MESSAGES...
- Next chance of light snow tonight through Fri morning
- More light snow Sat/Sat night
- Warm and windy weather for Mon/Tue
&&
.DISCUSSION...(Today Through Wednesday)
Issued at 311 AM MST Thu Dec 4 2025
Upper air analysis shows northwesterly flow continuing across the
central Great Plains...within broad cyclonic flow stretching across
the eastern 2/3rds of the CONUS. Surface analysis shows strong high
pressure across eastern SD into MN/IA. A warm front is crossing the
CWA...with surface obs showing temps steady or slowly rising
overnight. Some locations in the downsloping northeastern foothills
have seen temps rise 20 degrees in the last 3-4 hours. High today
will much warmer than yesterday...generally in the 30s to mid 40s. A
surface trough will bring breezy northwest this morning. Dry weather
is expected, but clouds will be increasing ahead of the next wave,
which rolls in tonight/Friday. Light snow will begin late this
evening through Friday morning, but little to no QPF is expected
across most locations. Weak upsloping will redevelop across the
northern Black Hills, which could bring 1-3" of accumulation. After
the next brief dry period, from Fri PM through Fri night, a
disturbance approach, accompanied by a 170kt jet streak crossing the
northern Rockies into the High Plains. A surface low is progged to
cross the Nebraska, drawing cooler air back into the CWA...with
highs in the 20s to low 30s. Another round of light snow will push
through...but this time a bit more widespread. Most areas are
expected to see up to an inch or two over an 18-20 hour
period...maybe slightly higher amounts again across the northern
Black Hills. Generally unsettled NW flow continues early next week.
However, models are showing enough warm air moving in to potentially
bring temps in the 50s Monday and Tuesday. With more disturbances
crossing the area, gusty winds are expected.
&&
.AVIATION...(For the 12Z TAFS Through 12Z Friday Morning)
Issued At 425 AM MST Thu Dec 4 2025
VFR conditions continue today and this evening. Breezy northwest
winds are expected north of Interstate 90. An incoming system will
bring light snow to portions of the area later tonight. Increasing
MVFR/IFR conditions are expected, especially across the Black
Hills through northwest South Dakota.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&
$$
DISCUSSION/KEY MESSAGES...13
AVIATION...13
Office: ABR
FXUS63 KABR 041138 AAA
AFDABR
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
538 AM CST Thu Dec 4 2025
.KEY MESSAGES...
- Downslope winds expected in the Sisseton Hills region today,
with gusts from 40-50 mph. This may create areas of
blowing/drifting snow.
- System late tonight into Friday bringing generally around an inch
or less of light snow.
- Snow chances (40-60%) return Saturday as a clipper system moves
through following by periodic lower chances (20-40%) through
early next week as more weather systems have the potential to
move through the region.
&&
.UPDATE...
Issued at 529 AM CST Thu Dec 4 2025
Aviation discussion updated below for the 12Z TAFs.
&&
.SHORT TERM /TODAY THROUGH FRIDAY AFTERNOON/...
Issued at 420 AM CST Thu Dec 4 2025
Area of stratus (with flurries) continues to advance eastward across
the CWA within the warm air advection regime. Warm front will
advance eastward across the CWA through the day as 925mb temps rise
to around +2C to +3C (HREF mean) across the southwest CWA. Although
across the far east, perhaps only -4C to -5C. This still equates to
highs in the 20s east, to the low/mid 30s across central SD. Bigger
story continues to be the downslope winds expected over the Coteau
today. HREF mean continue to indicate gusts 40-45 mph. Probs for 50+
mph do show a small/localized area of 20-40% in the immediate
downslope side of the Coteau. Tried to convey these speeds in the
forecast over there. PotBlowingSnow output continues with
drifting/patchy blowing over the eastern CWA.
Focus then shifts to the wave of low pressure moving east-southeast
across the area late tonight into Friday. Hi-res output continues to
show light snow/light QPF across the region as this wave moves
through. There is some variance in the hi-res reflectivity output in
just how expansive any pockets/areas of light snow will be. After
looking at various snowfall output/probabilities, it appears
accumulations will be around an inch or less for most areas.
&&
.LONG TERM /FRIDAY EVENING THROUGH WEDNESDAY/...
Issued at 420 AM CST Thu Dec 4 2025
The period begins Friday night into Saturday morning with another
clipper like low pressure system on our doorstep. The upper wave
associated with this system looks to pack a bit more of a punch than
the previous one mentioned above. There still some uncertainty in
the exact track of this low as model consensus remains within
reasonable agreement but also contains some slight differences.
Therefore, any slight adjustments in the track of the low will have
a big impact on who gets a good dose of snow and who doesn't. With
that said, the general agreement is pointing to a track that favors
the clipper just off to the southwest of our forecast area. This
would mean our southern and western zones may see more of an impact
from more snowfall and more wind during the day on Saturday. NBM
probabilities of seeing more than 1 inch of snow between early
Saturday and early Sunday are between 40-70 percent across our
western and southern most zones, while only between 15-30 percent
from north central sections of SD into northeast SD and west central
MN. For probs of more than 2 inches for the same time frame range
between 20-40 percent from east central SD/Watertown area west and
south through Clark and Redfield and then down toward the Miller and
Kennebec areas, while locales farther north and west of these areas
only stand a 5-15 percent chance. Certainly a system we'll have to
pay attention to in the next couple days as any changes in track of
the low will greatly affect snowfall amounts.
The northwesterly upper flow pattern that has been in place will
continue to remain in place across the region for the foreseeable
future. This will be mean continued periodic visits by more clipper
like lows through the region early to middle of next week.
Deterministic and ensemble solutions vary widely in the timing and
placement of any such waves moving through the region. Therefore,
it's more difficult to get into any specific inferences on the
weather conditions the CWA experiences Sunday through Wednesday of
next week. However, expect things to fall more in line with what
we've recently observed and experienced with bouts of snow or a
wintry mix along with bouts of arctic temperatures mixed in with
warming/melting trends.
&&
.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 529 AM CST Thu Dec 4 2025
Terminals KABR,KATY,KPIR,KMBG
MVFR CIGs will affect KABR/KATY at the start of the TAF period,
with lower CIGs in IFR (lake effect) across KMBG. Forecast is for
primarily VFR conditions to return later today, with more MVFR
CIGs (potentially IFR?) late in the TAF period as another wave of
low pressure moves in. With this low, comes chances for -SN with
MVFR VSBY which was used as a PROB30 group for the time being.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...TMT
SHORT TERM...TMT
LONG TERM...Vipond
AVIATION...TMT
