347
FXUS63 KFSD 072008
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
208 PM CST Sun Dec 7 2025

.KEY MESSAGES...

- Narrow band of light snow will move from west to east through
  the region into the early overnight hours. Amounts of snow
  generally stay less than 0.5" with pockets near 1" in the
  Buffalo Ridge.

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

- Confidence is high that winds Tuesday night into Wednesday may
  exceed advisory criteria with potential for 55+ mph winds in
  a few areas. We`ll need to monitor the snow pack and air temps
  closely to monitor blowing snow potential.

- Confidence is also moderate that arctic air will bring near
  advisory level wind chills to the region by next weekend.

&&

.DISCUSSION...
Issued at 204 PM CST Sun Dec 7 2025

THIS AFTERNOON: A minor shortwave continues to move across the
Dakotas early this afternoon, with the combination of dPVA and warm
advection leading to light snow.  The greatest intensity of snow
thus far has been tied directly to the stronger lobe of vorticity,
with weaker echoes associated with the broad warm advection. This
activity will track steadily east into the evening, with snowfall
amounts less than 0.5" in many areas.

TONIGHT: The favored track of mid-lvl vorticity southeast along the
Buffalo ridge will keep a risk for snow through the higher
elevations into the overnight hours. It`s possible a few areas could
see up to an inch of very fluffy snow by time the wave moves east
after midnight. Elsewhere, stratus will prevail under broad
warm advection AOA 850mb. Surface temperatures may begin to warm
through the night, with no strong drops expected.

MONDAY:  Mid-lvl ridging builds on Monday with broad warm advection
spreading throughout the Upper Plains.  While temperatures aloft may
warm well above freezing, we may struggle to realize these
temperatures given weaker southerly to southeasterly surface flow,
lingering stratus, and fresh snow cover. Have trended forecast
temperatures a bit lower over snow cover areas, with highs in the
upper 40s in south central SODAK.  One thing to watch will be minor
blowing snow along the higher elevations of the ridge given
favorable surface wind fetch.

TUESDAY-TUESDAY NIGHT: An active pattern will continue to send
multiple shortwave through the Northern US for much of the upcoming
7 day forecast.  One such wave crosses the Canadian Rockies and
moves into the Upper Plains late Monday night. Persistent warm
advection ahead of this wave, along with southwesterly breezy
surface winds, will advect near to above freezing temperatures into
the Tri-State area by Tuesday morning.  Again, minor
blowing/drifting snow could be possible Tuesday morning. This wave,
given favorable jet dynamics is expected to rapidly intensify
as it crosses North Dakota and northern Minnesota Tuesday, with
widespread precipitation well north of the CWA. Closer to home,
breezy to gusty westerly winds surge temperatures over the snow
pack towards the 40 degree mark, which should help settle the
fresh snowpack. As the wave passes Tuesday afternoon and
evening, scattered rain showers in the warm advection regime
likely develop along and north of I-90.

The passing surface low near the Twin Cities at 00z Wednesday will
surge an initial front through the CWA early in the evening, marking
the arrival of very strong cold air advection aloft. The true
surface front may lag a few hours later, and will gradually lower
temperatures through the night. A BIG concern with this system is
the rapid deepening of the upper low and development of a channel of
50 to 60+ knot low level winds on the western side of the clipper.
These low-lvl winds, at their current projected intensity, fall
outside the 30 year, 3-week climatology for this time of the year.
Raw model guidance would support gust of 45 to 55 mph over a large
portion of the CWA, and have again significantly boosted winds over
the populated NBM. High wind watches may be needed in some areas,
but will subsequent shifts to reexamine.  This strong but short-
lived burst of wind poses an uncertain risk to the existing snowpack
and the ability to loft it. It`s uncertain just how long we`ll stay
above freezing Tuesday, and if this will be long enough to stabilize
the very fluffy nature of the snow.  Blowing snow tools suggest that
if temperatures remain above 34 degrees for an extended time
snow may struggle to sufficiently loft across a widespread area.
However the concern would be as temperatures fall back below
freezing into Wednesday morning and moisture is again pulled out
of the snow. Also, if we see even higher sustained wind gusts
breaking the 45 knot mark, snow pack temperature may matter even
less as lofting probabilities cross the 50% threshold no matter
the age of the snow. All that said, continue to stay weather
aware if traveling Tuesday night into Wednesday.

WEDNESDAY-SATURDAY:  This stagnant pattern continues through the
upcoming weekend, keeping a persistent risk for snow moving into the
region about every 1.5 days.  After temperatures fall back into the
teens Wednesday, we`ll watch another wave arrive by Thursday.  Model
trends have swayed back towards more of a lighter nuisance event
moving through the Tri-State area Thursday.  A deeper and more
meridional tracking wave them moves through the Plains and
Great Lakes at the end of the week increasing confidence of a
fairly strong and gusty arctic air intrusion into the upcoming
weekend. Friday morning and Saturday morning would be potential
targets of concern for wind chill values near advisory levels.

Confidence starts to go out the window by next weekend as this
persistent northwesterly flow pattern may or may not send another
shortwave into the region.   As typical in this pattern, medium
range guidance and ensembles are wildly variable in their solutions.
Best word of advice through this week is to continue to monitor the
forecast if traveling.


&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1115 AM CST Sun Dec 7 2025

Clear to low VFR stratus lingers east of the James River at
mid-day. We`ll continue to see narrow corridor of warm advection
snow move east through the Dakotas into the evening, entering
western Minnesota and northwest Iowa early this evening. Brief
MVFR to IFR visibility reductions may be possible with ceilings
lowering below 1000ft AGL at times. Any accumulation will remain
less than 1".

Snow may linger over SW Minnesota into the early overnight
hours, as MVFR to IFR ceilings linger over most areas through
the night. Soundings suggest the shallow stratus deck is on the
edge of the DGZ, so can`t rule out lingering flurries, but
probability is too low to mention ATTM.

&&

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

&&

$$

DISCUSSION...Dux
AVIATION...Dux