sd discuss
Office: FSD
FXUS63 KFSD 271154
AFDFSD
Area Forecast Discussion
National Weather Service Sioux Falls SD
554 AM CST Thu Nov 27 2025
.KEY MESSAGES...
- A dry and chilly Thanksgiving is expected, with highs ranging
from the mid-20s where there is a snowpack to the mid-30s
along the Missouri River Valley.
- Our next storm system remains on track for Friday through
Saturday, with a slight southward shift in the heaviest
snowfall projections. With a potential for moderate to
briefly heavy snowfall rates across portions of southeast
South Dakota and Siouxland with the initial snow band Friday
afternoon/night, the Winter Storm Watch has been expanded to
cover most of our forecast area for Friday afternoon through
Saturday evening.
- This system will cause disruptions to post-Thanksgiving Day
travel, so be sure to keep up to date with the latest forecast
and be prepared to adjust your travel plans.
- It turns much colder at the start of next week, with the
potential for lows below zero degrees Sunday night/Monday
morning.
&&
.DISCUSSION...
Issued at 355 AM CST Thu Nov 27 2025
THANKSGIVING DAY: A quiet day for those traveling today with
partly to mostly cloudy skies and relatively light winds. Low
clouds drifting south into northern parts of the forecast area
may persist much of the day and combined with recent snowpack,
will hold high temperatures in the mid to even lower 20s north
of the I-90 corridor. Mid-level clouds currently sliding across
our southwest counties are expected to see more thinning, with
more afternoon sun over snow-free ground which should allow for
highs in the mid 30s through the Missouri River Valley.
FRIDAY-SATURDAY NIGHT: Main focus for the post-holiday period
remains on a strengthening storm system which will impact a
large portion of the northern Plains-Upper Midwest. The event
will begin for the local area with expansion/development of a
narrow band of snow west of I-29 by midday Friday in response to
increasing warm advection/mid-level frontogenesis beneath the
right entrance region of a 100+ kt upper jet. Model soundings
also indicate a neutrally stable to slightly unstable layer
above the frontal surface, which could aid in narrowing the snow
band with a potential for briefly heavy snowfall rates by Friday
afternoon and evening. This currently appears to be focused from
northwest to southeast across southeast South Dakota into the
Sioux City area. HREF localized probability matched mean (LPMM)
QPF for just Friday afternoon shows bands of 0.10 to 0.25" of
liquid with isolated higher pockets, which could translate to a
quick 1 to 3 inches of snow by Friday evening.
This band would then pivot northeastward through Friday evening,
with forcing for the snowband gradually weakening overnight as
the lead jet exits east and mid-level front begins to weaken.
Energy will become refocused across eastern Nebraska and Iowa
later Friday night through Saturday as the mid-upper trough
digs southeast into Iowa, becoming slightly negatively tilted
as a stronger upper jet digs into the base of the trough through
the central Plains. A broad area of light snow will continue
across much of southeast South Dakota and southwest Minnesota
during this time as the inverted trough slides through the area.
However, the greater potential for heavier rates has shifted a
bit south, still clipping areas along and east of the IA/MN
Highway 60 corridor with 70-90% probabilities of exceeding 6
inches of snow, and 40-70% probabilities of exceeding 8 inches.
Although probability of greater than 6 inches is lower across
southeast South Dakota/Siouxland (30-60% along and east of the
James River Valley), the potential for a heavier burst Friday
afternoon/evening is concerning given Friday is the start of the
post-holiday travel period. Add in that light snow will persist
through the following 24-30 hours into Saturday evening, opted
for expansion of the Winter Storm Watch across all but a few of
our counties in south central South Dakota.
Will also have to watch wind speeds/gusts, though it looks like
a good portion of this event will have our area in a slacker
pressure gradient along the inverted trough. As such, while
localized areas of blowing snow are possible, the greatest
impacts to visibility and travel will come from the falling
snow, with widespread blowing snow not currently anticipated.
Snow will gradually taper off from west to east through Saturday
afternoon/evening as the system moves into the Great Lakes.
SUNDAY ONWARD: Sunday could still be a little breezy to start
the day, but winds decrease through the day as high pressure
slides into the area. Overall, this should be the better travel
day of the 3-day post-Thanksgiving weekend for the local area
with regard to weather conditions. However, cannot predict how
quickly roads will improve so be sure to check the latest road
conditions before heading out.
The first half of next week will feature a much colder air
mass, with temperatures further limited by expected widespread
snow cover. Low level (925-850MB) temperatures Sunday-Monday
will reside in the favored temperature range (DGZ: -12 to -18C)
for what I like to call insta-flurries, so cannot rule out
scattered flurries with any low cloud coverage. However, models
differ on the amount of moisture within this layer, so will not
introduce this to the forecast at this time.
The colder low levels will translate to surface temperatures
well below normal as we head into early December, though the
latest models do not keep the significant cold around for long
with an upward trend in temperatures by the middle of next week.
Still, will have to watch for possible sub-zero low temperatures
Sunday night in response to clearing skies/light winds and fresh
snowcover.
&&
.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 554 AM CST Thu Nov 27 2025
IFR-lower MVFR stratus from northeast SD into southwest MN will
slowly sag southward today, with a brief period of LIFR ceilings
along the leading edge. Expect this to impact KHON much of the
day, but confidence is lower that the widespread stratus will
reach KFSD with HREF probabilities showing only 20-30% chance of
MVFR or lower ceilings reaching I-90/KFSD through the period.
As a result, have been more optimistic with the KFSD forecast,
but will monitor trends closely over the next 2-3 hours. It is
unlikely that this stratus will expand south of Highway 18 or
into the KSUX area.
Chances for deteriorating conditions will increase in the 6-12
hours beyond this forecast period as a developing winter storm
begins to impact the region.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...Winter Storm Watch from Friday afternoon through Saturday
evening for SDZ040-055-056-061-062-065>071.
Winter Storm Watch from Friday afternoon through Saturday
afternoon for SDZ038-039-052>054-058>060.
MN...Winter Storm Watch from Friday afternoon through Saturday
evening for MNZ071-072-080-081-089-090-097-098.
IA...Winter Storm Watch from Friday afternoon through Saturday
evening for IAZ001>003-012>014-021-022.
Winter Storm Watch from Friday afternoon through Saturday
evening for IAZ020-031-032.
NE...Winter Storm Watch from Friday afternoon through Saturday
evening for NEZ013-014.
&&
$$
DISCUSSION...JH
AVIATION...JH
Office: UNR
FXUS63 KUNR 271114
AFDUNR
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
414 AM MST Thu Nov 27 2025
.KEY MESSAGES...
- Expect snow Friday/Saturday with mostly minor travel impacts
per WSSI
- 10-20F below normal temperatures this weekend
- Additional snow may occur for the middle of next week
&&
.DISCUSSION...(Today Through Wednesday)
Issued at 153 AM MST Thu Nov 27 2025
08z surface analysis had weak ridge from central Canada into
eastern NE/KS. On the back side of the high, a stationary front
snakes from central MT into CO. Water vapour loop had northwest
flow over the northern Plains with next shortwave of interest
about ready to move into the northwest CONUS/southwest Canada.
Early morning weak shortwave associated with 140kt jet streak over
the CWA shaking out a few flurries per highway cameras/KUDX
WSR-88D radar returns. Main concern this forecast is impact of
upstream shortwave.
Today/tonight, northwest CONUS shortwave slips into the northern
Rockies. It will assist the development of weak low over central
MT which will transform stationary front into weak warm front,
slipping into the far southwest reaches of the CWA later tonight.
Weak lift along front will allow for thickening/lowering clouds
with low level southeasterly developing. Patchy light snow may
develop late. Temperatures will be near guidance.
Friday/Saturday, shortwave moves into the plains and then the
Midwest. MT surface low modestly strengthens as it moves southeast
along aforementioned surface boundary. 800-600mb frontogenesis
ahead of the surface low becomes increasingly well-defined as
modest QG-forcing ahead of shortwave moves through the CWA. Should
see a band of snow Friday morning shifting east of the CWA as it
intensifies, but weaker forcing will slip south over the CWA later
Friday into Saturday as boundary layer flow becomes northerly.
0-2km RH (>90%)/Froude numbers (>1) become favorable for some
upslope-ehnaced snow for the northern Black Hills Friday night
into Saturday. Latest probabilistic guidance suggests two areas of
concern for winter weather headlines. 1) Far northeast portions
of the CWA, including the Lemmon area where storm total snow
amounts may exceed 3". 2) The northern Black Hills where storm
total snow amounts may exceed 4". However, the 25-75th percentile
ranges are still quite large (1-6" for Bison for example), so will
not issue any headlines this morning given the uncertainty.
Northerly winds (15-25mph) behind surface low combined with
expected snowfall paint minor WSSI impacts, giving more credence
to taking a wait and see approach. Temperatures will be 10-20F
below normal.
Sunday through Thursday, northwest flow aloft continues with
splitting troughs. First batch largely misses the CWA
Sunday/Monday, but second batch may bring a shot of light snow for
the middle of next week per lift over low-level baroclinic zone
in place.
&&
.AVIATION...(For the 12Z TAFS Through 12Z Friday Morning)
Issued At 411 AM MST Thu Nov 27 2025
Areas MVFR/IFR CIGS/VSBYS due to low clouds/fog will affect far
northwestern SD today. Local MVFR CIGS over northeastern WY/far
west-central SD will lift this morning. Otherwise, VFR conditions
will prevail through the 28/06z, including the KRAP/KGCC
terminals. After 28/06z, a band of light snow may develop over the
area leading to local MVFR conditions.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&
$$
DISCUSSION/KEY MESSAGES...Helgeson
AVIATION...Helgeson
Office: ABR
FXUS63 KABR 271115 AAA
AFDABR
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
515 AM CST Thu Nov 27 2025
.KEY MESSAGES...
- Snow will return Friday into Saturday. Currently, there is a 30-80
percent chance of receiving more than 3 inches of snow throughout
central and northeastern SD, and a 30-70 percent chance of receiving
more than 5 inches of snow across central SD with this upcoming snow
event.
- 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 Sunday, Monday and Tuesday mornings.
&&
.UPDATE...
Issued at 514 AM CST Thu Nov 27 2025
Updated for the 12z Aviation Discussion below.
&&
.SHORT TERM /TODAY THROUGH FRIDAY AFTERNOON/...
Issued at 423 AM CST Thu Nov 27 2025
As of 10z, low clouds and fog have move in over north central and
northeastern SD. These low clouds and fog are causing localized
areas of lower visibilities at times. The fog should dissipate
this morning after the sun rises. An elongated high surface
pressure has moved in over central and northeastern SD today,
which will help to keep precipitation out and winds light.
Temperatures will be 5-15 degrees colder normal for the holiday
and Friday. High temperatures through Friday will be in the low
30s over south central SD and in the upper teens to 20s over
northern SD and west central MN, with low temperatures in the
teens to single digits. Wind chills will get down to the single
digits and the single digits below zero tonight.
Friday, the upper-levels have a small/weak ridge moving over SD. In
the mid- to low- levels under the ridge, a line of WAA pushes into
central SD Friday morning. This line of WAA has frontogenesis along
it that will help to develop a band of snow starting Friday morning.
This band of snow will move into central SD Friday morning before
slowly spreading to the east. There looks to be an strong initial
surge of snow Friday over an areas between the Missouri River and
James River. While models have place the highest rates Friday over
Walworth/Edmunds county to the southeast over Hyde/Hand county over
the past couple of runs, the highest snow totals could move due to
where the band and frontogenesis sets up on Friday.
Snowfall amounts during the day Friday until Friday night shows a
line with 30-80% chance for 3 inches or more from Mobridge to Miller
with the highest chances. The lower chances (around 20-40%) at the
edges of the line which includes Aberdeen to Clark on the eastern
edge of the line and Pierre on the western edge. There is then a 30-
60% chance for greater than 5 inches of snow until Friday evening
over southern Edmunds, Faulk, Hyde, and Hand counties as well as
slightly lower chances on the western edge of Spink county. These
chances increase as the overnight into Saturday time periods are
included (see long-term discussion below). Winds pick up slightly
Friday under the band, with gusts in the afternoon forecast to get
up to 25-30mph, strongest to the southwest of the highest snow
rates. These winds could lead to localized areas of patchy blowing
snow in central SD Friday. The snowfall probabilities Friday and the
ones on Saturday (more on this below) in combination with the fact
that this event will be happening the day after Thanksgiving and
many will probably be trying to travel, have lead to a winter storm
watch being issued for a few counties with the highest snow totals.
This watch area will most likely need to be updated as snow totals
continue to shift locations and amounts.
&&
.LONG TERM /FRIDAY EVENING THROUGH WEDNESDAY/...
Issued at 423 AM CST Thu Nov 27 2025
The main focus in the long term will be the ongoing snow event at
the start period along with much below normal temperatures
persisting through early December. Beginning 00Z on Saturday, a
fairly potent looking 500mb trough is progged to be tracking
eastward out of the Central Rockies into portions of the
Central/Southern Plains. This upper wave will have induced a 1006mb
Colorado low pressure system that is progged to track eastward into
KS/OK with an inverted trough extending northward into NE and SD.
During the daytime hours on Saturday, guidance takes this storm
system northeastward toward St. Louis by Saturday night and
eventually into the central and eastern Great Lakes the latter half
of the upcoming weekend.
A northwest to southeast oriented band of snow will already be
underway by the beginning of this period. There remains decent
agreement among guidance in tracking this snow east to southeast
during the day on Saturday with a gradual tapering off trend
expected from northwest to southeast Saturday afternoon into the
early evening. Easterly upslope flow Friday night into early
Saturday will turn more northeast to north on Saturday as the
inverted sfc trough passes through and exits our area to the east.
The WAA/frontogenesis induced heavier or more steady snowfall still
looks to occur during the overnight hours through about daybreak-mid
morning Saturday. Lighter snowfall will generally take hold the
remainder of the day before tapering off and ending by late afternoon
or early evening. There remains not much change in the overall
QPF/snowfall probabilities footprint across the forecast area. Given
the dynamics involved in this wave, parts of our area could be in
line to pick up at least a quarter of an inch of liquid precip.
Highest probabilities of seeing more than this amount range from 50-
80 percent on a line from the Mobridge to Faulkton to Huron. Lower
probs(20-50 percent) surround this area on both the north and east
side(Aberdeen/Watertown areas) and the the west and south
side(Pierre/I-90 corridor areas). Snowfall probabilities of seeing
more than 4 inches continue to highlight zones between the Missouri
and James Valleys or roughly from Edmunds County south through
Hyde/Hand and east through Spink and Clark Counties. These areas sit
at about a 70-90 percent chance of seeing more than 4 inches and
about a 50-70 percent chance of seeing more than 6 inches. As
mentioned earlier, a Winter Storm Watch has been issued for these
locations from mid morning Friday through late Saturday afternoon.
There will be some wind to accompany this storm system but nothing
comparable to our last clipper like system on Tuesday. Gusty winds
up to 30 mph will be possible Saturday afternoon across south
central SD. Some blowing and drifting along with reduced
visibility(especially during snowfall) will be possible through late
Saturday afternoon/early evening, but improvement expected after the
snowfall ends and winds diminish Saturday night.
A 1040mb sfc high pressure system is then set to build into the
region Saturday night into Sunday sending southward a reinforcing
shot of arctic air into our area that will persist into early next
week. This sfc high is then expected to shift east by Tuesday which
will promote a more southerly low level flow to take over only to be
followed by another frontal boundary passage that may deliver some
precipitation to parts of the area at the end of this period.
Daytime temperatures in the teens and low 20s on Saturday will take
a nose dive Saturday night falling into the single digits above and
below zero. A very cold end to the holiday weekend is expected with
daytime highs on Sunday only reaching the upper single digits above
zero to mid teens. Throwing in a little bit of wind(5-15 mph) will
produce wind chill values into the 15-20 below range. These much
below normal temperatures will prevail through the middle of next
week, even with a slow and slight warming trend expected. Daytime
temperatures in the 20s to low 30s may be possible by the end of
this period.
&&
.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 515 AM CST Thu Nov 27 2025
Terminals KABR,KATY,KPIR,KMBG
Low clouds and visibilities will continue to cause MVFR/IFR
conditions this morning over KABR, KMBG, and KATY. The low clouds
will continue to cause IFR/MVFR conditions through most of the day
today. KPIR is the exception as it has and will continue to have VFR
conditions though the day.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Winter Storm Watch from Friday morning through Saturday
afternoon for SDZ010-017>019-036-037.
MN...None.
&&
$$
UPDATE...12
SHORT TERM...12
LONG TERM...Vipond
AVIATION...12
