sd discuss
Office: FSD
FXUS63 KFSD 250448
AFDFSD
Area Forecast Discussion
National Weather Service Sioux Falls SD
1048 PM CST Mon Nov 24 2025
.KEY MESSAGES...
- Fog, including dense fog with visibility below half a mile,
continues overnight into the Tuesday morning commute.
- Rapidly intensifying storm system will bring strong winds
Tuesday with widespread 45 mph gusts likely by the afternoon.
Gusts to 60 mph are likely in the MO River valley.
- Rain changing to snow expected as far south as I-90, with
accumulating snow expected. Evening trends have been shifting
higher snowfall southward. Visibility impacts may be possible
in snow and wind into Tuesday evening.
- Holiday travel less likely to be impacted through
Thanksgiving, but greater travel risks develop Friday through
the weekend. Considerable uncertainty remains, but
probabilities for 1" snow near 90%, and 3" greater than 50%.
&&
.UPDATE...
Issued at 1025 PM CST Mon Nov 24 2025
A couple of things to note late this evening. First, fog
continues to expand over the area. Dense fog with visibility
below half a mile has remained generally transient and patchy
until about the last hour or so. May need a Dense Fog Advisory
within the next hour or two should observations continue to
deteriorate across the US Hwy 20 corridor into northwestern IA.
Second, 24.21z SREF and 25.00z hi-res guidance overall has
shifted southward with the axis of heavier snowfall. This would
bring higher totals than currently forecast - especially across
southwestern MN. Still awaiting some of the other 25.00z
guidance to come in, but would not be surprised to see an
increase in amounts and possible headline changes.
&&
.DISCUSSION...
Issued at 209 PM CST Mon Nov 24 2025
THIS AFTERNOON: Mid-lvl vorticity sliding through the mid-Missouri
River valley this afternoon continues to produce very light
rainfall across portions of the Tri-State area this afternoon.
Any QPF amounts are going to remain light.
TONIGHT: Short term guidance continues to hint at the potential for
scattered fog to develop late this evening as winds remain light and
boundary layer moisture remains elevated. Coverage of fog remains
too uncertain to issue an advisory at this point, but will need to
monitor trends this evening. A fast moving open wave currently
through the Northern Rockies will race into the Northern Plains
overnight. An increase in mid-lvl clouds will continue tonight, with
warm advection precipitation focusing well north of the CWA. However
an initial surge of low lvl cold air advection will enter the
Missouri River valley region by daybreak with a rapid increase in
winds likely.
TUESDAY: The aforementioned wave will continue to deepen as it
crosses the Dakotas and pivots slightly southeast in the afternoon.
Winds will spread through the MO River valley on the initial
surge of 925:850 mb cold air advection pushing higher terrain
areas of the river valley near high wind warning criteria into
mid-morning. Scattered rain showers may also develop on the
first synoptic surface boundary moving west to east mid-morning,
but coverage will stay on the lower side. A stronger synoptic
cold front pivots around the backside of the upper trough by
mid-day, with deeper cold advection and stronger downward
momentum transfer to the surface through the remainder of the
CWA. HREF guidance along with most deterministic guidance
suggests high potential for gusts 40 to 50 mph through the Tri-
State area into the evening. Will issue a localized high wind
warning for the higher terrain areas of the MO river valley with
a wind advisory elsewhere. Precipitation will also wrap round
the passing trough by mid-day, spreading a risk for light rain
turning to rain/snow and then to snow through the afternoon.
Undercutting low-lvl dry air may limit the southern extent of
precipitation, with greater focus for accumulating snow near and
north of Highway 14 where probabilities of 1"+ snow rise above
60%. While the wind will lead to some tricky travel at times,
anyone traveling northward in the state along Interstate 29
north of Brookings and Watertown will need to remain weather
aware.
WEDNESDAY: High pressure moves into the region for Wednesday as
this system moves well east of the area. A very cold day is likely
with highs struggling to rise out of the 20s. Overnight lows by
Thanksgiving morning fall into the teens and may be lower in any
area that experiences accumulating snowfall.
FRIDAY-MONDAY: Uncertainty is the key word in the forecast for the
post holiday travel timeframe from Friday through Sunday. Mid-lvl
ridging begins to increase late Thursday ahead of a deepening West
Coast trough. Guidance is converging on a solution that will place
a warm advection zone of snow through the Plains on Friday, with a
minor short wave crossing the advection zone enhancing lift locally.
The difficult challenge is pin pointing where this area of
precipitation develops. The GFS is further northeast with this
precipitation, with the ECMWF/CMC deeper and stronger with the
overall lift. Ensembles are also suggesting a fairly narrow corridor
of precipitation, with probabilities of 0.10+" over 70% from
Friday afternoon into Saturday morning. Probabilities of 0.50"+
are near or less than 10%, so depending on ratios this would
suggest an average 1-4" snow into Saturday morning. Have
increased PoPs into Friday night for portions of the CWA over
NBM guidance.
By Saturday, model agreement mostly falls apart as significant
differences remain between extended models on the 500 mb pattern
through the weekend. The ECMWF/CMC both a large and deeper phased
trough over the central US, effectively shoving any secondary round
of winter weather well south of the region. The GFS on the
other hand splits the flow, holding back a significant portion
of the upper trough over the southwestern US and creating a more
impactful pattern for widespread impacts through the Plains on
the weekend. Ensembles are still spread considerably this
weekend, leading to less than typical confidence this far out in
the forecast. A larger majority of the ECMWF members support
the drier solution than those of the GFS at this time. If
traveling for the holiday, continue to monitor the forecast!
&&
.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1025 PM CST Mon Nov 24 2025
Messy forecast through the period with stratus, fog, precip, and
wind concerns.
1. MVFR/IFR stratus prevails through much of the period once
ceilings drop. MVFR/IFR and even patchy LIFR fog is expected
through at least daybreak. Areas along the MO River to US Hwy 20
may see brief returns to VFR late Tuesday morning into the
afternoon, but should return to MVFR.
2. Precipitation moves into the area, initially as rain but
changing over to snow. Guidance has started trending south this
evening, but still think precipitation will remain focused along
and north of I-90. Snow accumulations are expected, with highest
amounts toward US Hwy 14. Expect continued visibility
restrictions with falling and blowing snow.
3. Northwesterly winds increase from west to east overnight and
into Tuesday morning. By early afternoon, gusts to 50 knots are
expected in south central SD. Gusts 30-45 knots will be common
elsewhere, and taper off from west to east toward the end of the
period.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...Wind Advisory from 9 AM to 9 PM CST Tuesday for SDZ068>071.
Wind Advisory from 9 AM to 6 PM CST Tuesday for SDZ038-052-053-
058-059-064.
Wind Advisory from noon to 9 PM CST Tuesday for SDZ039-040-
054>056-060>062-065>067.
High Wind Warning from 6 AM to 6 PM CST Tuesday for SDZ050-057-
063.
MN...Wind Advisory from 3 PM Tuesday to midnight CST Tuesday night
for MNZ071-072-080-081-089-090-097-098.
IA...Wind Advisory from 3 PM Tuesday to midnight CST Tuesday night
for IAZ001>003-012>014-021-022-032.
Wind Advisory from 9 AM to 9 PM CST Tuesday for IAZ020-031.
NE...Wind Advisory from 9 AM to 9 PM CST Tuesday for NEZ013-014.
&&
$$
UPDATE...SG
DISCUSSION...Dux
AVIATION...SG
Office: UNR
FXUS63 KUNR 250836
AFDUNR
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
136 AM MST Tue Nov 25 2025
.KEY MESSAGES...
- High winds and areas of light snow persist through this afternoon.
Gusts up to 70 mph likely across the western South Dakota
plains.
- Colder air remains entrenched through Thanksgiving with another
shot of even colder air this weekend plus snow chances.
&&
.DISCUSSION...(Today Through Monday)
Issued at 136 AM MST Tue Nov 25 2025
Water vapor imagery shows stout vorticity max pushing through NE
MT/W ND with shortwave trough axis extending southward through NE
WY into eastern CO. Surface cold front has surged south and east
of the area with colder air spilling into the forecast area.
Rain/snow showers are quickly shifting east of the forecast area,
with lingering light upslope snow in the Black Hills. Upper level
forcing will slowly push east of the forecast area as the trough
pivots into the Upper Midwest by 00Z tonight, with snow
diminishing rapidly this afternoon. Another inch or two is
possible across the Black Hills, with little to no accumulation
elsewhere.
High winds remain on track this morning into the afternoon. Steep
lapse rates, strong cold air advection, and 40-50+ knot winds atop
the mixed layer will support wind gusts up to 65-70 mph from NW SD
through the Pennington County plains into south-central SD today.
The winds will quickly diminish from west to east after 22-00z
this afternoon.
Northwest flow will continue Wednesday into Thanksgiving with
below average temperatures (~5-10F below normal) and generally dry
conditions. A few light snow showers/flurries are possible
Wednesday in the Black Hills as a weak wave ripples through the
northwest flow.
A much more active pattern is in store Friday through the weekend.
Split flow is forecast to develop by late Friday following an
initial shortwave that pivots through the Northern Rockies into
the Northern Plains by 00z Saturday. Given the messy, split flow,
ensembles show wide spreads re: surface low development and
location, which will have a large impact on overall snow threat.
However, broad large-scale ascent will be present Friday into
early Saturday and again Sunday with near-daily chances of light
snow Friday through Monday. The current forecast has the best
threat of accumulating snow (~70%+ probability of snow >4" Friday-
Monday AM) in the Black Hills given upslope enhancement; much less
confidence in snow potential elsewhere. In addition to the snow
chances, much colder air will surge into the region with highs in
the teens and 20s Sunday-Monday and lows near 0F each night.
&&
.AVIATION...(For the 06Z TAFS Through 06Z Tuesday Night)
Issued At 1003 PM MST Mon Nov 24 2025
Main aviation concern through this valid TAF period will be the
strong NW winds that will increase across the terminals after 06z
and continue throughout this TAF period. Winds have a high
likelihood of gusting up to 60 mph at the KRAP terminal with gusts
in the 40-45 mph range at the KGCC terminal. With this winds we
can expect some low level wind shear impacts at the KRAP terminal
developing around 14z.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...High Wind Warning until 5 PM MST /6 PM CST/ this afternoon for
SDZ001-012-013-025-026-031-032-041-043-044-046-047-049-072-
073-077-078.
Wind Advisory until 5 PM MST this afternoon for SDZ002-014-027-
030-042-074>076.
WY...High Wind Warning until 5 PM MST this afternoon for WYZ060.
&&
$$
DISCUSSION/KEY MESSAGES...SE
AVIATION...Woodward
Office: ABR
FXUS63 KABR 251007
AFDABR
Area Forecast Discussion
National Weather Service Aberdeen SD
407 AM CST Tue Nov 25 2025
.KEY MESSAGES...
- Rain will transition to all snow by this afternoon, and continue
into this evening. The highest snowfall amounts by late this evening
of around 4 to 8 inches are forecast over grassy and elevated
surfaces, mainly northeast of a line from Aberdeen to Rauville and
Clear Lake.
- Strong winds will gust 40 to near 60 mph today, strongest over
south central SD. The combination of the snow and strong winds will
result in visibility down to 1/2 mile or less this afternoon, lowest
over far northeastern South Dakota and west central Minnesota. While
the snow will come to an end this evening, blowing snow will linger
through the overnight hours over far eastern SD and west central MN.
High Grassland Fire Danger Index values are expected over south
central SD today.
- Below normal temperatures will continue through the beginning of
December. Below zero wind chills area possible over northern SD each
morning Thursday through Sunday. Wind chills will fall into the
teens to near 20 below zero Monday and Tuesday morning.
&&
.SHORT TERM /TODAY THROUGH TONIGHT/...
Issued at 407 AM CST Tue Nov 25 2025
Strong winds gusting out of the northwest 40 to near 60 mph over
central South Dakota during the morning hours will expand to eastern
South Dakota and west central Minnesota this afternoon, and linger
over northeastern South Dakota and western Minnesota this evening.
Winds just west of Jones County are already busting 40-56 mph as of
3 AM this morning. 3-hourly height falls of 4-7mb are expected over
central SD 15-18Z and around 4-5mb over the eastern third of the
state along with far western MN by from 21Z-00Z Wednesday in our
cold air advection.
Precipitation amounts have increased across the entire forecast area
for today into tonight. A quicker transition to snow as currently
noted over north central SD would result in another increase in snow
amounts. The largest change is over northeastern SD where amounts,
with nearly a doubling over our east central SD counties. For
example, Webster has gone from around 0.3" to 0.6". This increase in
precipitation amounts mainly in the form of snow this afternoon, and
the strong winds will lead to areas of 1/4 mile visibility in
blowing snow. Near blizzard conditions are possible for at least a
couple of hours transitioning from west to east from 19-23Z this
afternoon. We will be watching for the potential for higher snowfall
rates during this time, as upgrades may be needed to the current
headlines. We did upgrade Marshall, Roberts, Day, Grant, Traverse,
and Big Stone Counties to a Winter Storm Warning for this event. As
a result of the upgrade to a Warning, the Wind Advisory for Grant
County was allowed to be dropped. The remaining Wind Advisories that
line up with Winter Weather Advisories for east central SD have been
kept.
Behind the bulk of the precipitation we will still need to be
watching for the potential for snow squalls west of the MO River 15-
18Z and across the MO River area by 21Z. The highest 0-3km lapse
rates near 7C/km stay over western and central SD, with the
potential for snow squalls shifting more to our southeast after 21Z.
Additional short term headlines may be needed.
An additional concern will be a small potential for light freezing
rain from 12-15Z over the eastern slopes of the Sisseton Hills
(mainly a small portion of southwestern Traverse County) as
temperatures transition from rain to snow. Given the low potential,
freezing rain was not included in the forecast at this time, but we
will continue to monitor area webcams and surface reports for the
possibility.
Strong winds will be the main concern for areas west of the Missouri
River through south central South Dakota through this afternoon.
Wind gusts of 40 to near 60 mph are expected, strongest over south
central South Dakota. Limited precipitation and dry fuels will lead
to high Grassland Fire Danger Index values over south central South
Dakota today. Relative humidity values will still only fall to
around 70 percent at the lowest today. While fire weather concerns
remain due to the strong winds, the increased chance of
precipitation and higher relative humidity has diminished concerns
more than what we were forecasting yesterday.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Issued at 407 AM CST Tue Nov 25 2025
The snow is forecast to be out of eastern SD and west central MN by
Wednesday morning, however the stronger winds will take a bit longer
to move to the east. There is a 30-50% chance the wind gusts through
the morning Wednesday will be gusting greater than 30 mph along and
east of I-29, with higher chances along the eastern side of the
Prairie Coteau. These winds should dissipate through the morning and
afternoon as higher surface pressure starts to move over central and
eastern SD. The higher pressure stays over the area through Thursday
night, helping to keep precipitation chances out during that time.
The upper and mid-levels of the atmosphere will have northwest flow
over SD and west central MN that push colder air in from the north.
This will cause temperatures to continue to drop through the
weekend, getting to be 5-10 degrees below normal Wednesday and
Thursday and potentially even colder during the weekend.
Snow chances start to increase early Friday morning along the
western edge of the high pressure over central SD. This line of snow
forms along a line of WAA that move into central SD Friday. Models
vary the location of the line and how widespread the snow could be,
with some models keeping it mainly over central SD and others having
it over central and northeastern SD. The variability in the models
also continues to snowfall amounts, with a 30-60% chance for an inch
or more of snowfall being spread out over the area. Compared to past
model runs, the chance for more snowfall has increased while the
location of the highest chances keeps changing location. The
variability in current models as well as with past model runs
continues to cause low confidence in the location and amounts of the
snowfall. Friday night into Saturday and Sunday, the upper-levels
have shortwaves moving over the state while the surface has higher
pressure moving in again. This would then push the precipitation
chances out of central and northeastern SD Saturday and Sunday,
however the variation in the models continues. This causes some
models to continue to have snow over the area during the weekend
while others keep it out. This again is a time period to watch over
the next few models runs to see if the models start to come to an
agreement as there could be many traveling after the holidays.
&&
.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1116 PM CST Mon Nov 24 2025
Terminals KABR,KATY,KPIR,KMBG
VFR conditions will fall to IFR vsby and cigs as a fast moving
clipper brings moderate snow, strong northwest winds and blowing
snow to the region. Conditions will improve west to east Tuesday
evening.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Winter Storm Warning from 9 AM this morning to 6 AM CST
Wednesday for SDZ021.
Winter Weather Advisory until 6 PM CST /5 PM MST/ this evening
for SDZ003>005-009-010.
Winter Weather Advisory until midnight CST tonight for SDZ006.
Winter Storm Warning until 6 AM CST Wednesday for SDZ007-008.
Winter Storm Warning until midnight CST tonight for SDZ011.
Wind Advisory until 6 PM CST /5 PM MST/ this evening for
SDZ015>017-034>037.
Wind Advisory from 9 AM this morning to 6 PM CST this evening
for SDZ018-019.
Winter Weather Advisory from 9 AM this morning to midnight CST
tonight for SDZ018>020-022-023.
Wind Advisory from noon today to 8 PM CST this evening for
SDZ020-022-023.
High Wind Warning until 6 PM CST /5 PM MST/ this evening for
SDZ033-045-048-051.
MN...Winter Storm Warning from 9 AM this morning to 6 AM CST
Wednesday for MNZ039-046.
&&
$$
SHORT TERM...06
LONG TERM...12
AVIATION...20
