sd discuss
Office: FSD
FXUS63 KFSD 280906
AFDFSD
Area Forecast Discussion
National Weather Service Sioux Falls SD
306 AM CST Fri Nov 28 2025
.KEY MESSAGES...
- Snow pushes into the area this morning and persisting through
Saturday. Snow amounts have increased, with most of the area
expected to see more than 4 inches of snow, with more than 6
inches for areas along and east of I-29. Areas south of I-90
toward US Highway 20 may see a glaze of ice.
- Have updated headlines in response to increased totals.
Expanded the Winter Storm Warning north and west, and added
Gregory county to the Winter Weather Advisory.
- Expect disruptions to travel today through the weekend; travel
will become difficult if not impossible in some areas. Keep up
to date with the latest forecast, check road conditions before
traveling, and be prepared to adjust your plans. If you must
travel, keep a preparedness kit in your car.
- Much colder temperatures are expected most of next week with
the lows down to the single digits and wind chills below 0F.
&&
.DISCUSSION...
Issued at 304 AM CST Fri Nov 28 2025
THROUGH SATURDAY NIGHT: Main focus of this forecast is on the
upcoming winter system, with numerous winter weather headlines in
effect across the region and potentially major disruptions to travel
expected through the post-Thanksgiving weekend. Discussion broken
into synopsis, accumulation/rates, winds, and headlines.
SYNOPSIS: Lee-side low pressure in the eastern Rockies develops
through this morning with the first pass of WAA and jet streak
moving into the region by daybreak. Frontogenesis increases with the
WAA, which will lead to a band of snowfall moving east through the
day and into the evening hours with the mid level wave. Expect a
struggle with saturation initially, so snow may take a bit to reach
the ground. Additionally, we may see brief periods of freezing
drizzle or a mix of FZDZ/SN this evening and tonight south of I-90
along the southern MO River Valley and the US Hwy 20 corridor as we
lose the saturation to the DGZ.
Tonight, we begin to see the surface low eject out of CO into NE,
with continued WAA and the next mid/upper level trough. We may see a
lull in snow with some drier air moving in, but will see the next
round of precip move in from the west fairly quickly so stayed
pretty heavy handed with POPs while trying to show the lull a bit.
Expect snow to continue through the day Saturday, with moderate snow
at times. May see additional banding, although guidance is varied on
the placement of the strongest f-gen. Low pressure and upper trough
move east of the area through Saturday night, with much colder air
in its place.
ACCUMULATIONS/RATES: Snow totals have increased a couple of inches
most places with the increase in QPF for this event. Most of the
area is now looking at 4" or more of snow, with areas east of I-29
looking at 6" or more. Locations in northwestern IA east of IA State
Hwy 60 may see more than a foot of snow (20-50%+). Areas in the
James River Valley may see some amounts toward 6" or more, but there
is a little more uncertainty in that area with guidance more split
here. Generally through the event, snowfall rates of 0.25" to 0.75"
per hour. However, enhancement in the f-gen/other forcing this
evening/tonight may lead to 1" per hour rates across portions of
northwestern IA. Could see some brief heavier rates Saturday as well.
WINDS: Winds start off northeasterly today and into tonight, with
the strongest winds across south central SD gusting to 30 mph
through the day and into the evening. With falling snow, expect
reduced visibility and some blowing/drifting. Winds shift to
northwesterly Saturday, and will be breezier across the area. Again,
main impacts with widespread wind gusts 25-35 mph will be the
blowing and drifting potential. Be prepared for reduced visibility
and difficult travel conditions.
HEADLINES: With the increase in snow amounts, have tweaked the
headlines slightly. Added Gregory county to a Winter Weather
Advisory. The Winter Storm Warning has been expanded west and north,
to now include most of the I-29 corridor. Further expansion to the
Winter Storm Warning is possible, if trends west of I-29 into the
James River Valley continue to increase.
SUNDAY ONWARD: Given the focus on the short term, no changes to the
extended along with a limited discussion. Sunday looks to be dry and
colder as high pressure moves into the region. Highs Sunday will
struggle to get out of the teens, with lows in the single digits
either side of zero. Colder temperatures, 10 or so degrees below
average, continue through next week, although some locations should
moderate back closer to normal. A couple of quick moving
waves/troughs moving through could lead to some light precipitation
chances early and mid week, although confidence is low given model
disagreements and overall lack of moisture. Periodic breezy
conditions, which could lead to some blowing/drifting issues on
Monday. Wind chills fall below zero at times.
&&
.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1118 PM CST Thu Nov 27 2025
For areas east of the James River Valley VFR conditions are
present at issuance. For areas to the west, some patchy low
level stratus is streaming in from the northwest. This has kept
those western ceilings at MVFR. This stratus is expected to
scour out as much drier air aloft mixes down over the next few
hours.
Meanwhile a winter storm is approaching out of the west. By daybreak
a band of snow is expected to set up over central South Dakota and
progress east through the morning. As it does so ceilings will once
again decrease to MVFR to IFR. Snow should begin to impact KHON by
late morning to mid-day. KFSD and KSUX should expect snow around
noon to the early afternoon. Late this afternoon into the
evening snowfall rates are expected to increase and visibility
will lower to 2 SM. KFSD and KSUX could see an extended period
of visibility falling to less than 1 mile toward the end of the
period.
Winds Friday will be southeasterly and increase through the morning,
gusting 20-28 kts for areas along and west of the James River
Valley. To the east gusts will generally be around 15 kts or
less.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...Winter Storm Warning from noon today to midnight CST Saturday
night for SDZ055-056-062-066-067-069>071.
Winter Weather Advisory from 9 AM this morning to noon CST
Saturday for SDZ038-039-053-054-059>061-065.
Winter Weather Advisory from noon today to midnight CST
Saturday night for SDZ040.
Winter Weather Advisory until noon CST Saturday for SDZ050-052-
057-058-063-064-068.
MN...Winter Storm Warning from noon today to midnight CST Saturday
night for MNZ071-072-080-081-089-090-097-098.
IA...Winter Storm Warning from noon today to midnight CST Saturday
night for IAZ001>003-012>014-020>022-031-032.
NE...Winter Storm Warning from noon today to midnight CST Saturday
night for NEZ013-014.
&&
$$
DISCUSSION...SG
AVIATION...AJP
Office: UNR
FXUS63 KUNR 280925
AFDUNR
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
225 AM MST Fri Nov 28 2025
.KEY MESSAGES...
- Slick travel due to snow/blowing snow expected from two rounds
of snow through Saturday morning with the highest impacts
tonight
- 10-20F below normal temperatures this weekend
- Light snow Tuesday/Wednesday
&&
.DISCUSSION...(Today Through Thursday)
Issued at 219 AM MST Fri Nov 28 2025
09z surface analysis had stationary front from central MT through
central CO with weak low over WY. Water vapour loop had upper
trough moving into the northern Rockies with lead 90kt jet streak
zipping across WY. Lift ahead of jet streak over frontal boundary
causing a north/south-oriented band of radar returns over western
SD per KUDX radar loop. Some flurries/light snow reaching the
ground. Effect of upper trough the main concern.
Today/Saturday, upper trough moves east/southeast across the
plains. Surface low moves southeast and deepens as inverted trough
feature slides through the CWA. Initial band of snow per
frontogenesis/moderate 800-600mb theta-e advection will intensify
as it moves east. Not much moisture behind first band with a lull
in precipitation expected, but this will change as upper trough
moves through tonight per moderate QG-forcing/frontogenesis
behind developing cold front trailing surface low. Latest guidance
has upped the ante with regard to forcing/mass output along with
isallobaric forcing behind the cold front. Result is an uptick in
QPF/snow amounts and gusty northerly winds. ECMWF EFI depicts
50-80th percentile snowfall with SPC HREF mean QPF rising compared
to previous ensemble guidance. Not a huge fan of advisory creep,
but feel combination of increased snow on the plains (1 to locally
4 inches) and stronger winds will create a hazardous snow/blowing
snow combination tonight into Saturday morning. Have raised
Winter Weather Advisories to account in collaboration with
surrounding offices. Froude number >1/0-2km RH ~90% for the
northern Black Hills tonight, so will continue headlines there,
but have pushed back timing to be more in sync with latest
guidance and warmish temperatures this afternoon. Speaking of
temperatures for today, didn't stray too far from guidance over
the southern half of the CWA near warm front, but did drop MaxTs
over northwestern SD. Saturday looks chilly with highs 10-20F
below normal.
Sunday will be relatively dry and cold. Some deterministic
guidance depicts snow showers Sunday afternoon, but ensemble
guidance not on board. Left forecast dry for now. Warmer
temperatures are expected Monday ahead of next upper trough that
zips through bringing a chance of light snow Tuesday/Wednesday.
The end of next week will be unsettled with temperatures near
normal.
&&
.AVIATION...(For the 06Z TAFS Through 06Z Friday Night)
Issued At 1035 PM MST Thu Nov 27 2025
MVFR-IFR cigs can be expected across NW SD through the period. VFR
conds elsewhere through Friday morning. Breezy south winds can be
expected across northeast WY tonight. A sfc trough will move into
the area Fri morning, with winds shifting northwest. Snow will
develop Friday evening, with deteriorating conds expected all
places.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...Winter Weather Advisory until 11 AM MST Saturday for SDZ001-002-
014-078.
Winter Weather Advisory from 5 PM this afternoon to 11 AM MST
Saturday for SDZ012-013-024>026-031-032-043-072-073.
Winter Weather Advisory from 8 PM MST /9 PM CST/ this evening to
11 AM MST /noon CST/ Saturday for SDZ027-030-041-042-044-
046-047-049-074>077.
WY...Winter Weather Advisory from 5 PM this afternoon to 11 AM MST
Saturday for WYZ057-060.
Winter Weather Advisory from 5 PM this afternoon to 8 AM MST
Saturday for WYZ054>056-058-059.
&&
$$
DISCUSSION/KEY MESSAGES...Helgeson
AVIATION...JC
Office: ABR
FXUS63 KABR 280518 AAB
AFDABR
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1118 PM CST Thu Nov 27 2025
.KEY MESSAGES...
- A band of snow develops Friday morning in central and north
central South Dakota, moving northeast before broadening into
light snow Friday night and Saturday. Winter weather headlines
are in place for this system.
- Below normal temperatures continue through at least the middle
of next week. Coldest timeframe is Sunday/Monday with temps 15
to 25 degrees below normal. Wind chills as cold as 5 to 15
degrees below zero forecast for Sunday and Monday mornings.
&&
.UPDATE...
Issued at 518 PM CST Thu Nov 27 2025
Forecast remains on track. No major changes planned, but will
likely need tweaks to hourly sky cover and temps.
&&
.SHORT TERM /THIS EVENING THROUGH FRIDAY NIGHT/...
Issued at 301 PM CST Thu Nov 27 2025
Stratus layer continues to migrate slowly southwest having cleared
Aberdeen and not quite to Watertown, will likely linger across
central South Dakota with light flow at 850mb under a ridge. Where
it has cleared, models suggest the potential for fog re-develoment,
up along the ND/SD state line in particular. Will wait and see where
the clouds clear before updating fog mention.
Focus is on the system for Friday. There is a narrow axis of mid
level warm advection providing the impetus for a band of snow along
a corridor across central South Dakota, that weakens as it shifts
east, with a lull in advection before another broader area of weak
warm advection kicks in resulting in additional light snowfall
amounts. So how intense will these snowfall rates get? NAM BUFKIT
profiles suggest at times a very deep dendritic growth zone with
these cold temperatures aloft, and low wind speeds limiting breakup,
which is confirmed by NBM snow ratios of 16-18 to 1. HREF
probabilities of snow rates in excess of 1 inch per hour are zero
however. Average for ensembles for Mobridge/Miller/Huron run about
0.4" liquid, translating to about 6 for snowfall where this band
sets up. As such, posted a winter storm warning along and to the
northwest of the original watch to cover CAM placement.
This will be very blowable snow given snow ratios, however in
regards to the blowing snow model, the mean NBM highest winds
(sustained) will require inch per hour snowfall rates to approach
blizzard criteria, and as mentioned earlier, HREF doesn't support
such high snowfall rates.
As for temperatures next several days, we remain under an arctic
airmass. NBM temperatures bottom out Sunday/Monday, aided by the
newest addition of snow. Northwest low level flow will keep
temperatures from cratering Sunday morning. The same can not be said
for Sunday night/Monday morning with a shift to southerlies, however
NBM does bring in some cloud cover, a thick layer of cirrus according
to GFS 300mb analysis and BUFKIT profiles, in line with an
approaching shortwave. Lower level moisture appears limited to
Nebraska at this time and the atmosphere is too dry in the subcloud
layer to support precipitation reaching the surface.
&&
.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1115 PM CST Thu Nov 27 2025
Terminals KABR,KATY,KPIR,KMBG
IFR stratus will continue to move through the region. IFR/MVFR
conditions will become more widespread early Friday morning ahead
of some moderate snow.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Winter Storm Warning from 9 AM CST /8 AM MST/ Friday to noon CST
/11 AM MST/ Saturday for SDZ003-009-010-015>017-034-036-037.
Winter Weather Advisory from 9 AM Friday to noon CST Saturday
for SDZ004.
Winter Weather Advisory from noon Friday to noon CST Saturday
for SDZ005-006-018-019.
Winter Weather Advisory from 3 PM Friday to noon CST Saturday
for SDZ007-008-011-020>023.
Winter Weather Advisory from 6 AM CST /5 AM MST/ Friday to noon
CST /11 AM MST/ Saturday for SDZ033-035-048-051.
MN...None.
&&
$$
UPDATE...20
SHORT TERM...07
AVIATION...20
