083
FXUS63 KFSD 262107
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
307 PM CST Wed Nov 26 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 moves in Friday morning and exits from
  west to east through Saturday night. There is currently a
  70-90% chance of snowfall amounts greater than 6 inches
  especially over portions of southwest Minnesota and northwest
  Iowa. For this reason, a Winter Storm Watch has been issued
  for Friday afternoon through Saturday evening.

- This system could cause disruptions to post-Thanksgiving Day
  travel, so be sure to keep up to date with the latest forecast
  and be prepared to make any changes to 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 300 PM CST Wed Nov 26 2025

It`s been a chilly day as low clouds have gradually eroded leading
to some sunshine across a large part of the area. With that, highs
have only climbed to the upper-20s to low-30s this afternoon. A cold
night is expected, with lows into the teens to low-20s, coldest
where there is a snowpack. Those locations could also see some
patchy fog develop late tonight into early tomorrow morning, but
dense fog is not expected at this time. Thanksgiving day looks dry,
but cold with highs in the mid-20s where there is a snowpack, to mid-
30s along the Missouri River Valley. Some guidance indicates the
potential stratus to develop in spots mainly north of I-90
tomorrow morning, lifting/eroding through the afternoon. If
that occurs, then it could be even colder in spots and there
could be a few flurries. But either way, impactful weather is
not expected for Thanksgiving Day.

Main focus is on our next storm system moving in for the post-
Thanksgiving travel period. On Friday, an upper-level trough will
swing through the Pacific Northwest into the Rockies and then into
the Plains by Saturday. At the surface, a low pressure system will
develop out of the Rockies late Friday and move northeastwards into
the mid-Mississippi Valley by Saturday evening, with deterministic
guidance differing in the path of this low. In terms of what we can
expect on the ground, starting Friday morning a northwest to
southeast oriented band of snow looks to develop across central
South Dakota, which would put this locally along the James River
Valley. This band will likely lift northeastward through the day on
Friday and intensify due to increasing WAA at 850 mb helping to feed
moisture into the system. While this band is ongoing, snow from the
low pressure system will move into northwest Iowa in tandem with the
upper-level trough, allowing for additional periods of heavier snow.
Snow looks to exit the area from west to east Saturday night, with
the GFS getting the precipitation out of here by midnight Saturday
night/Sunday morning, while the EC and Canadian are a bit slower,
getting the snow out of here just after sunrise Sunday.

In terms of amounts, ensemble probabilities show a roughly 70-90%
probability of snowfall amounts exceeding 6 inches over southwest
Minnesota into adjacent portions of northwest Iowa (assuming an
average of a 15:1 SLR). With such a strong signal for heavy snow
combined with increased travel expected post-Thanksgiving, have went
with a Winter Storm Watch in these areas for Friday afternoon into
Saturday night. The rest of the area east of the James River has a
40-70% chance of over 6 inches of snow, so further expansion of this
watch will likely be needed as confidence increases. With this
starting out as a banded snowfall event, there will likely be a
narrow corridor where snowfall amounts will be heaviest. Ensembles
show a 15-35% chance of snowfall exceeding 12 inches between Friday
and Saturday night over parts of southwest Minnesota and northwest
Iowa, so there is a potential for a high-end event if everything
comes together at the right time. Please follow the forecast as
we continue to provide new updates!

One last thing to note about this system is that winds do not look
to be as strong as what we saw with yesterday`s system. However,
wind gusts do look to pick up from west to east through the day on
Saturday to around 30 mph as the low pressure system deepens off to
our east. With that, there could be some blowing snow issues
as the snow is wrapping up into Saturday evening, but it`s
unclear at this time how much of a reduction of visibility can
be expected in any blowing snow. This is because it will depend
on where the greatest overlap of highest snowfall amounts and
strongest winds will be, with those details not likely to be
resolved until we get the higher-resolution guidance in. After
the snow ends, very cold air settles in with lows dropping to
the single digits Saturday night. High temperatures on Sunday
will likely struggle through the teens, with lows Sunday night
potentially below 0. Uncertainty grows from Monday onwards, but
overall we look to remain mostly dry and cold through the middle
of next week.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1103 AM CST Wed Nov 26 2025

Stratus continues to linger across a large part of the area to start
the period, but it is continuing to erode along the edges and this
will continue through the early-to-mid-afternoon. With that,
VFR conditions are currently expected from the mid-afternoon
today onwards at all TAF sites. Can`t rule out some fog tonight
(30-50% chance) especially where there is snow on the ground
(like KHON) as winds diminish, but confidence was not high
enough to include in the TAF at this time.

Some guidance also indicates the potential for additional low-
stratus to develop late tonight and linger into tomorrow morning,
especially for areas north of I-90 and even more so for
southwest Minnesota. However, this may develop just north and
east of KHON and KFSD, so just hinted at some stratus potential
starting at 10z tomorrow in the TAFs. Confidence was not high
enough to go with sub-VFR CIGS at this time as there is only a
20-30% chance of CIGS less than 3 kft at KHON and KFSD.

Northwesterly winds will continue to diminish through the afternoon,
but still gusting upwards of 25-30 kts east of US Highway-75 for the
remainder of this afternoon. Winds will be light, around 5-8
kts, tonight into tomorrow morning.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
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.
NE...None.

&&

$$

DISCUSSION...Samet
AVIATION...Samet