sd discuss
Office: FSD
FXUS63 KFSD 020436
AFDFSD
Area Forecast Discussion
National Weather Service Sioux Falls SD
1036 PM CST Mon Dec 1 2025
.KEY MESSAGES...
- Wintry cold, below normal temperatures continue through
early next week.
- Chances for light snow return Tuesday night 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 208 PM CST Mon Dec 1 2025
Northwest flow aloft brings minor warming aloft to the area
overnight into Tuesday, lifting the DGZ a little higher and limiting
the moisture within this layer. This supports little to no
precipitation tonight into most of Tuesday. With lighter winds in
place tonight at the surface and little to no cloud cover, lows
should drop into the single digits, above and below normal.
Slightly warmer conditions are expected Tuesday as a wave moves into
the area. Warm advection and re-saturation of the DGZ is expected
from west to east through the afternoon into the evening, with the
better saturation north of I-90. One note is that the DGZ will be a
bit on the high side and while it does saturate in the afternoon, a
dry layer in the lower levels may slow any precipitation
development. There is also a small chance for some mixed
precipitation, but that should mainly occur with the lighter
precipitation as heavier precipitation should bring better wet
bulbing and drop the low level thermal field below zero and support
mainly snow. At this time snowfall amounts should remain less than
an inch with the better chances north of I-90.
Behind this wave colder air will surge south with the stronger cold
air advection in the lower levels Tuesday night into Wednesday
morning. A few gusts around 30 mph will be likely during this time,
which will aid in dropping wind chills to 5 below to 15 below zero.
A pool of cold air will be in place Wednesday into Thursday morning,
but high pressure will bring lighter winds. This will allow
temperatures to fall to 5 below to 15 below zero. When coupled with
a light wind, wind chill values could fall to 20 below to 25 below
zero at times.
Friday through Monday will see northwest flow aloft with a few
weaker waves traversing the flow. Overall agreement on timing of
these weaker waves is pretty low, but the main thing that is
consistent is that only minor precipitation amounts are currently
expected. Temperatures during this time frame will remain below
normal.
&&
.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1032 PM CST Mon Dec 1 2025
Mostly VFR conditions will persist this TAF period with occasional
MVFR/IFR vsbys. Taking a look at satellite imagery, starting to
see a bit of fog develop across areas east of I-29 this evening.
As such, added in some MVFR to IFR fog into KFSD and KSUX through
mid-morning. Otherwise, pockets of light snow return by Tuesday
afternoon with a cold front. Lastly, light and variable winds
overnight will become more southerly to southeasterly to end the
TAF period.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&
$$
DISCUSSION...08
AVIATION...05
Office: UNR
FXUS63 KUNR 020515
AFDUNR
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1015 PM MST Mon Dec 1 2025
.KEY MESSAGES...
- Mild/seasonal temperatures Tuesday. Cold Wednesday. Back to
mild and seasonal temperatures Thursday and Friday.
- Highest chances of accumulating snow will be over the northern
Black Hills and Bear Lodge Mountains. Less than an inch of snow
expected on the plains.
&&
.DISCUSSION...(This Evening Through Monday)
Issued at 205 PM MST Mon Dec 1 2025
Water vapor and upper level analysis show a longwave, positively
tilted upper trof extending from the Northern Plains into the
southern Rockies and southern High Plains. Additionally, a shortwave
ridge extends into the Pacific Northwest with a shortwave trof
immediately behind it in the Gulf of Alaska. At the surface, a warm
front extends through central South Dakota, allowing temperatures at
20Z to range from the mid to upper 30s behind the warm front to the
teens for locations ahead of the front. Some of the heavier snow
covered areas are still sitting in the 20s.
For tonight, warm front will slowly progress eastward as a surface
low over Alberta begins to dive southeastward through Saskatchewan.
Low temperatures tonight behind the warm front will be around
average, in the mid teens, while single digit lows will continue
across the far eastern portions of the forecast area.
Tuesday/Wednesday, the upper trough moves through the Canada Prairie
Provinces into the Great Lakes, pushing a cold front through almost
the entire forecast area by 12Z Wednesday. Upper level energy
splits, with the main forcing passing north and south of the area.
However, weak forcing and modest moisture and frontogenesis should
allow for some light rain and snow across the area. With northwest
flow aloft, the northern Black Hills and Bear Lodge Mountains should
be able to pick up higher snowfall amounts due to upslope
conditions. Model ensembles range from 1 to 6 inches, with the 25th
to 75th percentiles in the 2 to 4 inch range. With a longer duration
of light snow and the max 6 hour snow accumulation 1.5 inch or less,
will forgo any winter weather headlines at this time. As for
temperatures, Tuesday will once again be mild ahead of the cold
front, but Wednesday will be cold, with highs only in the teens and
20s.
Active northwest flow continues through early next week, with
additional disturbances Thursday night and Friday, and another
Saturday and Saturday night. With all of these systems, the northern
Black Hills and Bear Lodge will be the favored area for the highest
precipitation amounts. As for temperatures, 850 temperatures stay at
or above 0C for Thursday and Friday, drop to -5C late
Saturday/Saturday night, then begin to warm to 0C to 5C early next
week.
&&
.AVIATION...(For the 06Z TAFS Through 06Z Tuesday Night)
Issued At 1012 PM MST Mon Dec 1 2025
An approaching system will bring increasing high and mid-level
clouds to the area this evening with chance of snow showers in the
Black Hills after 08-10z. More widespread precipitation chances
overspread the area after 16-18z from west to east with MVFR/IFR
and transient LIFR conditions in low clouds and snow.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&
$$
DISCUSSION/KEY MESSAGES...Smith
AVIATION...SE
Office: ABR
FXUS63 KABR 020533
AFDABR
Area Forecast Discussion
National Weather Service Aberdeen SD
1133 PM CST Mon Dec 1 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 Tuesday
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 1133 PM CST Mon Dec 1 2025
A quick update was done to include the freezing fog near the
Missouri River. Both PIR and MBG have reported freezing fog with
visibilities down to 1/4 mile. Webcams in PIR show this shallow
fog layer well, with not as robust spacial coverage on MBG webcams
at this time. Expect 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.
&&
.DISCUSSION...
Issued at 115 PM CST Mon Dec 1 2025
At 1 PM CST, skies are mostly sunny. Southwest winds are around 5 to
15 mph with some of the ridge tops gusting up over 25 mph.
Temperatures are warming through the single digits above to teens
above zero. There are even a few places (south central South Dakota)
trying to nudge their way up into the low 20s.
A surface trof/warm front is over the northern high plains/Dakotas
region this afternoon. The front is forecast to advance eastward,
nearing the border of Minnesota and the Dakotas around 3 PM CST
Tuesday. Low level WAA really gets going over this CWA later this
evening and during the overnight hours tonight into Tuesday. Surface
winds will maintain a direction somewhere between southerly and
westerly tonight through Tuesday. Most of the WAA period will be
spent saturating the column down. But, there may be times between
09Z Tuesday and 03Z Wednesday, when enough forcing/lift for
saturation may happen, and light precipitation would occur. Very
limited qpf with this scenario in the models/ensembles. The CWA will
probably maintain some sort of horizontal thermal gradient, where
central South Dakota could warm up enough that precipitation
transitions from snow to freezing rain to rain, while north central
and northeast South Dakota stay cold enough for precipitation to
just be snow. When the cold front chases this warmer air southward
out of the region Tuesday night (basically at or after 03Z
Wednesday), there could be enough of a "wringing out" of any
available low level moisture, to produce a period of CAA stratus and
light snow/snow showers briefly in the forcing/lift zone of the cold
fropa. Otherwise, it looks like breezy/windy north winds develop
Tuesday night, post-cold-frontal, with sustained winds establishing
in the 15 to 30 mph range with some occasional higher gusts.
Tonight, temperatures will cool off rapidly after ~4 PM CST with
clear skies and generally light south or southwest winds. Later
tonight, there should be increasing cloudiness over the CWA and low
level WAA kicking in, such that temperatures will begin to slowly
warm late tonight into Tuesday morning, especially across central
and north central South Dakota. The warming continues on Tuesday
from west to east, as warmer air overspreads the vast snowfield in
place over the Dakotas and Minnesota. Then, temperatures should turn
sharply colder behind a southward moving cold front Tuesday night.
So, upper ridge over the western CONUS/upper trof over the eastern
CONUS describes the basic flow pattern aloft throughout the period.
But, it is an active period of northwest flow with several shortwave
impulses forecast to sweep southeastward into the country's mid-
section throughout the period. And, a few of these shortwaves are
expected to bring precipitation chances through this CWA.
For now, looking at one possible brief run-in with precipitation on
Friday, and then another following close on its heels on Saturday.
These are fast-moving, low-qpf producing systems, so confidence is
pretty low just now on when/where/how much details.
Also, beyond the below normal cold temperatures slated for
Wednesday/Wednesday night in the post-cold frontal environment, low
confidence in the temperature forecast with 25th to 75th percentile
spread in both low and high temperatures exceeding 5 degrees (and
a lot of 10+ degree spreads) throughout the entire period beyond
Wednesday. Even Wednesday/Wednesday night's spreads are more than 5
degrees. But, in that case, the question is will it be really cold
or really, really cold! So, the warm up for Thursday/Friday and
again next Monday is in question.
&&
.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.
&&
$$
UPDATE...06
DISCUSSION...10
AVIATION...06
