sd discuss
Office: FSD
FXUS63 KFSD 021136
AFDFSD
Area Forecast Discussion
National Weather Service Sioux Falls SD
536 AM CST Tue Dec 2 2025
.KEY MESSAGES...
- Patchy fog this morning may briefly reduce visibility to
below one mile. Use caution during the morning commute as fog
may have led to some slick spots.
- Wintry cold, below normal temperatures continue through early
next week.
- Chances for light precipitation, mostly snow, return late
this afternoon into Wednesday with a passing cold front.
Behind the front, wind chills of -10 to -25F look
increasingly likely for Wednesday night into early Thursday.
- Details remain uncertain, but additional snow chances
continue this weekend into early next week.
&&
.DISCUSSION...
Issued at 303 AM CST Tue Dec 2 2025
TODAY: Patchy fog this morning has been occasionally reducing
visibility to below one mile. Fog could lead to isolated slick spots
during the morning commute. Temperatures have fallen into the single
digits to below zero.
We'll warm up a bit ahead of a cold front moving through the region
later this afternoon through this evening. However, did drop highs a
couple of degrees from the previous forecast as the snowpack should
temper the impact of the WAA. Highs in the 20s and 30s - warmest in
south central SD. As the front moves through, expect some light
precipitation. A mix of precipitation is possible as the front moves
through, mainly at the onset. Once we get slightly deeper saturation
and heavier precipitation, temperatures should drop with wet bulb
temps cooling below zero and switching the p-type to snow. Guidance
this morning is holding on to these slightly warmer temperatures
aloft just a bit longer than yesterday. Any snow accumulations will
be light, less than half an inch, and focused along/north of I-90.
Can't rule out a light glaze of ice for areas with mixed
precipitation before we transition to snow.
TONIGHT-WEDNESDAY: Initial push of cold air moves in behind the cold
front, and we'll be a bit breezy because of this and the compressed
SPG tonight into Wednesday. Any snow should taper off through the
overnight hours. Challenge through Wednesday and into Wednesday
night is the non-diurnal temperatures. Temperatures tonight into
Wednesday look to be relatively steady through the day. Breezy winds
will keep wind chills below zero, even during the day Wednesday.
Arctic high pressure slides south Wednesday into early Thursday,
bringing light winds behind another push of CAA. Light winds and
clearing skies help temperatures tank by early Thursday morning.
Lows Wednesday night fall into the teens and single digits below
zero, with wind chills as low as -25 F.
THURSDAY NIGHT ONWARD: Another cold front looks to move through the
area late Thursday night into Friday, which could bring another
chance for light snow. Otherwise, northwesterly flow prevails into
the early part of next week. As mentioned in the previous
discussion, guidance remains quite varied on the details of the
waves passing through, so confidence is low in any snow chances and
potential snow amounts. Below to near average temperatures continue
through the weekend and into early next week with occasional breezy
conditions.
&&
.AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 528 AM CST Tue Dec 2 2025
Patchy fog, mainly across river valleys and east of the Buffalo
Ridge, has been dropping visibility briefly down to 1 SM or
less. Fog should mix out through the morning hours. Light
precipitation moves across the area later this afternoon and
into tonight. A mix of precipitation is possible, but most of
the precip should be snow. Any accumulations will be light (less
than half an inch) and should remain north of I-90. Guidance is
handling stratus today and especially behind the cold front
poorly. Precip and stratus may drop to MVFR/IFR categories.
Winds shift from light and generally south to southwesterly this
morning to northwesterly toward the end of the period. Gusts
by Wednesday morning increase to around 20 knots.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&
$$
DISCUSSION...SG
AVIATION...SG
Office: UNR
FXUS63 KUNR 021121
AFDUNR
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
421 AM MST Tue Dec 2 2025
.KEY MESSAGES...
- Upslope-enhanced snowfall for the northern/Wyoming Black Hills
through early Wednesday
- Thursday through early next week, northwest flow aloft will
push a series of disturbances through the region bringing
periodic chances for light precipitation
&&
.DISCUSSION...(Today Through Monday)
Issued at 131 AM MST Tue Dec 2 2025
08z surface analysis had low over central SK with a warm front
into western NE, just about through the far eastern reaches of the
CWA. Water vapour loop had upper trough over western Canada into
the Pacific northwest with 140kt jet streak zipping over the
western BC coast. Lead shortwave energy over MT/ID creating some
light radar returns, some of which area starting to brighten as
they hit the higher elevations of the northern/Wyoming Black
Hills. Upper trough and upslope the the main forecast concerns in
the short term.
Today/tonight, upper trough moves southeast with the main pieces
of energy passing well to our southwest and to our northeast.
Synoptic forcing rather light with weak QG-forcing/low level
frontogenesis. Canadian surface low will drag a cold front
through the area later today/tonight, which will focus the main
QPF chances for the plains. Not expecting much QPF on the plains
with rain mixing in east of the Black Hills ahead of the cold
front, quickly changing to snow behind it. The main story will be
the upslope enhancement for the northern/Wyoming Black Hills.
Froude numbers already above 1 early this morning with increasing
0-2km RH today, becoming saturated tonight. Forecast soundings
suggest the best upward vertical motion will be in the dendritic
growth zone tonight, which will fluff up the snow. Latest HREF
LPMM 24-hour QPF gives about 0.50" liquid equivalent precipitation
by Wednesday morning. HREF probabilistic depictions show 70-100%
chance >0.25" QPF and 50% chance 0.50" QPF. Subjective pattern
recognition and high resolution deterministic model output suggest
these values reasonable. Will hoist a Winter Weather Advisory for
the northern/Wyoming Black Hills to account. Considered putting
headlines up for northern Campbell/Crook County Plains, but not
coming up with enough snow/impacts to issue at this time.
Isallobaric forcing behind the cold front supports breezy/locally
windy spots. Temperatures will be near guidance.
Wednesday will 10-20F colder than today with a bit of snap in the
air per northwest winds averaging 12-22 mph. Upslope snow should
quickly wane in the morning.
The rest of the forecast looks unsettled as northwest flow aloft
propels a series of disturbances through the northern Plains.
We'll be on the edge of the warmer air initially, but the latest
ensemble guidance shows a slow warming trend into early next week,
albeit with increasing temperature spreads. Best chance of
accumulating snow will continue to be over the northern Black
Hills given expected boundary layer flow regime.
&&
.AVIATION...(For the 12Z TAFS Through 12Z Wednesday Morning)
Issued At 417 AM MST Tue Dec 2 2025
Highly variable MVFR/IFR conditions due to light snow (possibly
mixed with light rain where temperatures rise above freezing) is
expected this morning across northeastern WY and far western SD,
including the KRAP terminal. More widespread precipitation chances
overspread the area this afternoon from west to east with areas
of MVFR/IFR conditions developing, persisting into tonight. LIFR
conditions will occur over the higher elevations of the Black
Hills tonight.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...Winter Weather Advisory from noon today to 6 AM MST Wednesday
for SDZ024.
WY...Winter Weather Advisory from noon today to 6 AM MST Wednesday
for WYZ057.
&&
$$
DISCUSSION/KEY MESSAGES...Helgeson
AVIATION...Helgeson
Office: ABR
FXUS63 KABR 021107
AFDABR
Area Forecast Discussion
National Weather Service Aberdeen SD
507 AM CST Tue Dec 2 2025
.KEY MESSAGES...
- Freezing fog with visibilities down to 1/4 at times, and light
icing, will remain possible early this morning, mainly near the
Missouri River.
- A quick moving disturbance will push through the region today
into early Wednesday, kicking off a 30-50% chance of light snow
over north central and northeast South Dakota and a wintry mix
of mainly rain/snow across central South Dakota.
- Very cold air across the region Wednesday and Wednesday night,
with lows in the single digits below and teens below zero. Wind
chills may reach 15 below to 25 below zero in the James River
valley.
- Snow chances (20-35%) return Friday/Saturday as more clipper
systems potentially move through the region.
&&
.SHORT TERM /TODAY THROUGH WEDNESDAY AFTERNOON/...
Issued at 504 AM CST Tue Dec 2 2025
Relatively quiet but cold conditions persist for most locations.
Temperatures vary widely with subzero readings mainly across parts
of northeast SD with single digits above zero elsewhere such as
central SD. Skies remain clear for the time being in our east
while high clouds are starting to thicken across the western
Dakotas. Favorable wind direction across the Missouri Valley is
producing another round of low stratus downwind of Lake Oahe and
Lake Sharpe. Within some of these areas, dense fog has led to low
visibility at times in the Pierre and Mobridge areas. Hi-res
guidance had pointed to expansion of some of this fog eastward
toward the James Valley through the early morning hours, but has
sense backed off. This will be a trend we'll have to keep an eye
on through daybreak.
For today, clouds will be thickening out ahead of a warm front that
is progged to shift west to east across the forecast area. Low level
WAA pattern will develop and try and scour out the arctic air that's
been in place. This will be most successful across our western zones
where temperatures will reach the low to mid 30s. Sub-freezing temps
are anticipated across our east. Southwest flow across the Prairie
Coteau will lead to another round of gusty winds in the downslope
areas by mid to late morning through at least mid afternoon. There
could be localized blowing snow effects in that area. Clouds will
continue to thicken in the low to mid levels by midday into the
afternoon. Low pressure is progged to track southeastward across
eastern ND into west central MN this afternoon. Light precipitation
in the form or mostly light snow will be possible across northeast
SD and west central MN where BUFKIT profiles suggest the temperature
profile through the saturated column remains subfreezing. However,
farther west across central SD, some of that warm air will win out
allowing for the potential for a rain/snow mix or just plain rain
for a period of time this afternoon. As the low levels begin to cool
late in the day, a period of a wintry mix or freezing rain will be
possible. Guidance continues to suggest QPF will be rather limited
through the entirety of this event, so anticipate minimal impacts
from a light coating of snow or light glaze in areas that see
freezing precip.
That area of low pressure will continue southeast and drag a strong
cold front through the forecast area this evening. Winds increase of
the north and northwest. Any leftover moisture will accompany the
fropa with the potential to see a few more snow showers or flurries
into the overnight hours. A CAA pattern sets in overnight with the
leading edge of a much colder air mass sinking southward into our
area early Wednesday. That pattern is expected to persist through
most of the day on Wednesday. Temperatures are likely to be warmest
early in the morning on Wednesday and then we should see falling
temperatures through the morning and midday hours. Temps may
stabilize for a brief time the first half of the afternoon, but
anticipate readings will start to plummet by the late afternoon
areas. Winds will be strongest during the morning and early
afternoon hours leading to wind chill values between 5 and 15 below.
&&
.LONG TERM /WEDNESDAY EVENING THROUGH MONDAY/...
Issued at 504 AM CST Tue Dec 2 2025
Surface high pressure centered over the region at 00Z Thursday will
shift southeast into IA by 12Z Thursday. Southerly winds increase
between 06Z and 12Z Thursday with warm air advection developing as
well. Therefore, it appears lows Wednesday night may be closer to
06Z, with steady/rising temperatures up through 12Z. Apparent T
grids still show wind chills from 25 below to 30 below zero in the
James River valley Wednesday night.
GEPS/GEFS/ENS 500mb heights are in good agreement in the mid/upper
level pattern featuring a persistent northwest flow aloft during the
rest of the extended period. There are a couple waves that moves
southeast across the region during this time, but with low
confidence on timing and precip chances/placement. Right now, the
highlight is on Friday night into Saturday with the highest chances
(20-30%) in the forecast. GEFS/GEPS/ENS all show some light QPF over
the region as a wave of low pressure slides to our south and we
potentially receive light snowfall accumulations across the CWA.
Precip chances may eventually increase over the coming day or two.
Temperatures are a bit uncertain as well as the Northern Plains see
a battle of air masses, with swings of relative mild air (20s/30s)
and colder arctic air with periods of lows in the single digits
above and below zero. Inherited max/min temp forecasts reflect this,
while low confidence remains on the actual numbers as shown in
larger spreads of the 25th/75th values in the NBM.
&&
.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1133 PM CST Mon Dec 1 2025
Terminals KABR,KATY,KPIR,KMBG
LIFR conditions in freezing fog have developed at MBG and PIR
by 05Z with visibilities down to 1/4SM and VV001. Expect freezing
fog to diminish in coverage and intensity by 10-12Z as high
clouds move in from the west and surface winds increase slightly
and shift out of a more southerly direction. Otherwise, at least
MVFR conditions in fog were also introduced to ABR/ATY by 08-09Z
through 12-16Z Tuesday. Confidence is low in the lower LIFR
conditions developing at ABR and ATY overnight.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
SHORT TERM...Vipond
LONG TERM...TMT
AVIATION...06
FXUS63 KABR 021156 AAA
AFDABR
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
556 AM CST Tue Dec 2 2025
.KEY MESSAGES...
- Freezing fog with visibilities down to 1/4 at times, and light
icing, will remain possible early this morning, mainly near the
Missouri River.
- A quick moving disturbance will push through the region today
into early Wednesday, kicking off a 30-50% chance of light snow
over north central and northeast South Dakota and a wintry mix
of mainly rain/snow across central South Dakota.
- Very cold air across the region Wednesday and Wednesday night,
with lows in the single digits below and teens below zero. Wind
chills may reach 15 below to 25 below zero in the James River
valley.
- Snow chances (20-35%) return Friday/Saturday as more clipper
systems potentially move through the region.
&&
.UPDATE...
Issued at 542 AM CST Tue Dec 2 2025
The aviation discussion has been updated for the 12Z TAFS.
&&
.SHORT TERM /TODAY THROUGH WEDNESDAY AFTERNOON/...
Issued at 504 AM CST Tue Dec 2 2025
Relatively quiet but cold conditions persist for most locations.
Temperatures vary widely with subzero readings mainly across parts
of northeast SD with single digits above zero elsewhere such as
central SD. Skies remain clear for the time being in our east
while high clouds are starting to thicken across the western
Dakotas. Favorable wind direction across the Missouri Valley is
producing another round of low stratus downwind of Lake Oahe and
Lake Sharpe. Within some of these areas, dense fog has led to low
visibility at times in the Pierre and Mobridge areas. Hi-res
guidance had pointed to expansion of some of this fog eastward
toward the James Valley through the early morning hours, but has
sense backed off. This will be a trend we'll have to keep an eye
on through daybreak.
For today, clouds will be thickening out ahead of a warm front that
is progged to shift west to east across the forecast area. Low level
WAA pattern will develop and try and scour out the arctic air that's
been in place. This will be most successful across our western zones
where temperatures will reach the low to mid 30s. Sub-freezing temps
are anticipated across our east. Southwest flow across the Prairie
Coteau will lead to another round of gusty winds in the downslope
areas by mid to late morning through at least mid afternoon. There
could be localized blowing snow effects in that area. Clouds will
continue to thicken in the low to mid levels by midday into the
afternoon. Low pressure is progged to track southeastward across
eastern ND into west central MN this afternoon. Light precipitation
in the form or mostly light snow will be possible across northeast
SD and west central MN where BUFKIT profiles suggest the temperature
profile through the saturated column remains subfreezing. However,
farther west across central SD, some of that warm air will win out
allowing for the potential for a rain/snow mix or just plain rain
for a period of time this afternoon. As the low levels begin to cool
late in the day, a period of a wintry mix or freezing rain will be
possible. Guidance continues to suggest QPF will be rather limited
through the entirety of this event, so anticipate minimal impacts
from a light coating of snow or light glaze in areas that see
freezing precip.
That area of low pressure will continue southeast and drag a strong
cold front through the forecast area this evening. Winds increase of
the north and northwest. Any leftover moisture will accompany the
fropa with the potential to see a few more snow showers or flurries
into the overnight hours. A CAA pattern sets in overnight with the
leading edge of a much colder air mass sinking southward into our
area early Wednesday. That pattern is expected to persist through
most of the day on Wednesday. Temperatures are likely to be warmest
early in the morning on Wednesday and then we should see falling
temperatures through the morning and midday hours. Temps may
stabilize for a brief time the first half of the afternoon, but
anticipate readings will start to plummet by the late afternoon
areas. Winds will be strongest during the morning and early
afternoon hours leading to wind chill values between 5 and 15 below.
&&
.LONG TERM /WEDNESDAY EVENING THROUGH MONDAY/...
Issued at 504 AM CST Tue Dec 2 2025
Surface high pressure centered over the region at 00Z Thursday will
shift southeast into IA by 12Z Thursday. Southerly winds increase
between 06Z and 12Z Thursday with warm air advection developing as
well. Therefore, it appears lows Wednesday night may be closer to
06Z, with steady/rising temperatures up through 12Z. Apparent T
grids still show wind chills from 25 below to 30 below zero in the
James River valley Wednesday night.
GEPS/GEFS/ENS 500mb heights are in good agreement in the mid/upper
level pattern featuring a persistent northwest flow aloft during the
rest of the extended period. There are a couple waves that moves
southeast across the region during this time, but with low
confidence on timing and precip chances/placement. Right now, the
highlight is on Friday night into Saturday with the highest chances
(20-30%) in the forecast. GEFS/GEPS/ENS all show some light QPF over
the region as a wave of low pressure slides to our south and we
potentially receive light snowfall accumulations across the CWA.
Precip chances may eventually increase over the coming day or two.
Temperatures are a bit uncertain as well as the Northern Plains see
a battle of air masses, with swings of relative mild air (20s/30s)
and colder arctic air with periods of lows in the single digits
above and below zero. Inherited max/min temp forecasts reflect this,
while low confidence remains on the actual numbers as shown in
larger spreads of the 25th/75th values in the NBM.
&&
.AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 542 AM CST Tue Dec 2 2025
Terminals KABR,KATY,KPIR,KMBG
LIFR conditions will persist at KPIR as a result of locally dense
fog leading to vsbys down to 1/4SM and VV001. These conditions are
likely to prevail through sunrise until about 13-15Z as higher
clouds thicken and winds some around to a southwest to west
direction. Otherwise, expecting VFR conditions to return at KPIR
and prevail for KABR/KATY/KMBG into the afternoon hours. Low level
clouds thicken and conditions will be back to MVFR cigs later this
afternoon and evening. A disturbance moving through the region
will generate light snow for terminals in the east like KATY and a
rain/snow mix or a freezing rain/snow mix this afternoon and
evening at KPIR. MVFR vsbys will be possible at these terminals
due to the precip. Light to moderate south to west winds expected
through today before turning more northwest late in this TAF cycle
and increasing with gusts up to 20-25 knots.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...Vipond
SHORT TERM...Vipond
LONG TERM...TMT
AVIATION...Vipond
