648
FXUS63 KFSD 091203
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
603 AM CST Tue Dec 9 2025

.KEY MESSAGES...

- A winter system will bring periods of rain, wintry mix, light
  snow, and strong winds to the region today. Strong westerly
  winds with gusts between 45-60+ mph could blow and/or drift
  our existing snowpack created near-whiteout to whiteout
  conditions at times this evening and overnight. However, some
  uncertainty remains.

- A busy week will continue with a risk of precipitation nearly
  every 1.5 days. Most of the precipitation events will remain
  light, but the systems on Thursday and Saturday will bear
  watching.

- Confidence is also moderate to high (50%-70%) that arctic air
  will bring near advisory level wind chills to the region by
  next weekend.

&&

.DISCUSSION...
Issued at 340 AM CST Tue Dec 9 2025

TODAY & TONIGHT: An active day ahead! Taking a look across the area,
high clouds continue to stream into the area with another push of
increasing mid-level warm air advection (WAA) this morning. Between
this and southerly to southwesterly surface winds, this will create
favorable conditions for more milder temperatures today with highs
closer to the upper 30s to mid 40s for most areas and 50s across
southcentral SD. With this, our focus shifts northwards as a quick
moving clipper progresses through the upper plains bringing our next
precipitation chances (50%-70%). With soundings continue to show a
warm nose of +4 to +7 degrees C between 800:900mb, most of the
precipitation will likely start as a wintry mix of freezing rain and
rain initially along and north of I-90 this morning. While this
could lead to a light glaze of ice mainly along and north of the
U.S. Highway-14 corridor, diurnal heating into the early afternoon
should allow things to transition to mainly rain through the early
evening. Now on to the main concern which are the stronger winds.

A tightening SPG and strong push of cold air advection (CAA) with a
cold front will likely lead to increasing winds speeds from this
afternoon into the overnight hours with the strongest winds likely
occurring overnight. Current thoughts are wind gusts between
45-55 mph are expected with pockets of up to 60+ mph possible
mainly across our higher elevation areas. With this in mind, the
blowing and drifting of our remaining snowpack is expected but
to what degree continues to be the plaguing question. Most of
the uncertainty revolves around how the rain and mild temperatures
mentioned above affect the blowable nature of the snow and if a
crust forms to keep most of it in place. While there`s an argument
for both sides the uncertainty with this was enough to keep our
Winter Storm Watch in place for now after collaborating with
neighboring offices this morning. Nonetheless, be prepared for
rapid reductions in visibility on the evening commute as surface
winds continue to strengthen. Lastly, as temperatures continue
to fall overnight, could see some additional snow showers swing
through portions of southwestern MN around midnight (06z).
However, accumulations will likely only amount to a dusting
(<1") if any.

Looking into the rest of the week, Additional chances for snow
return on Thursday and Saturday. However, locational differences
between mid to long-range guidance continues to lead to uncertainty.
Nonetheless mostly light accumulations are expected. Heading
into the weekend, arctic air will filter into the region leading
to colder temperatures and even colder wind chills. With this
in mind, advisory level wind chills aren`t out of the question
especially across southwestern MN by Sunday morning. This
sentiment is agree upon in the ensembles with most members
showing 50%-70% probabilities of wind chills at or less than -25
degree across areas northeast of a Huron to Beresford to Ida
Grove, IA line.,

&&

.AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 550 AM CST Tue Dec 9 2025

Mostly VFR conditions will transition to a mix of conditions
this TAF period. Taking a look at satellite imagery, a few
pockets of valley fog are developing this morning as high clouds
stream in. We`ll likely see conditions trend to MVFR cigs and
lower this afternoon as a winter system brings periods of rain
and wintry mix to the region. Otherwise, a strengthening LLJ
will help develop strong westerly winds in excess of 45-60+ mph
as early as this afternoon with LLWS up to 55kts. We`ll likely
see these conditions persist into the overnight especially
overnight. Lastly, areas of blowing snow could further reduce
vsbys especially across northwestern IA and portions of far
southeastern SD.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...Winter Storm Watch from this evening through Wednesday morning
     for SDZ067-070-071.
     Winter Storm Watch from noon CST today through Wednesday
     morning for SDZ038>040-052>056-058>062-064>066-068-069.
     High Wind Warning from noon today to 3 AM CST Wednesday for
     SDZ050-057-063.
MN...Winter Storm Watch from this evening through Wednesday morning
     for MNZ080-081-089-090-098.
     Winter Storm Watch from noon CST today through Wednesday
     morning for MNZ071-072-097.
IA...Winter Storm Watch from this evening through Wednesday morning
     for IAZ001>003-012>014-020>022-031-032.
NE...Winter Storm Watch from this evening through Wednesday morning
     for NEZ013-014.

&&

$$

DISCUSSION...05
AVIATION...05