383
FXUS63 KFSD 090943
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
343 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 45-55 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 /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1047 PM CST Mon Dec 8 2025

VFR ceilings will begin this period, but last only a short while as
the next storm system moves in this morning. By mid-to-late morning
we`ll begin to see ceilings decrease to MVFR and lower along Highway
14. Lower ceilings will progress south with the system.

After sunrise a storm system will move into the area from the
northwest. Areas along and north of Highway 14 will likely see a
wintry mix including freezing rain/drizzle. Ice accumulations are
expected to remain low, a light glaze to a hundredth of an inch. As
the storm drifts southeast through the late morning, precipitation
will transition over to light rain and expand in geographic
coverage. Rain slowly tapers off from west to east in the early
evening. Rain will linger over southwest Minnesota and northwest
Iowa this evening, eventually transitioning back to snow. This will
then taper off after midnight.

Light and variable winds overnight will begin to increase after
sunrise Tuesday morning. Winds will then become westerly, then
northwesterly behind a strong cold front (associated with the
previously mentioned storm) that passes through the region beginning
in the late morning. Winds will increase drastically over a short
period of time. Widespread gusts of 25-40 kts are expected by
09.21Z. Winds continue to increase and by 10.00Z gusts of 40-45 kts
will be common region wide with a few 50+ kt gusts possible. Gusts
of this magnitude are expected to continue through the end of the
period. Some reductions in visibility due to blowing and drifting
snow are likely. In addition, LLWS is expected at all three TAF
sites beginning after noon. Speed shear up to 50 to 55 kts are
expected and will continue past the end of the period.

&&

.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...AJP