824
FXUS63 KFSD 310857
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
257 AM CST Fri Jan 31 2025

.KEY MESSAGES...

- A bit cooler with highs in the upper 30s and 40s today but
  well above normal temperatures in the 40s and low 50s on
  Saturday. Sunday will see mild highs but likely some falling
  afternoon temperatures.

- A band of snow will be possible Sunday night into Monday with
  decent agreement amongst the models on some accumulations
  especially north of I-90. Monday morning could see some slower
  commute times and slick roads.

- No significant winter storms expected next week, but near to
  below normal temperatures and multiple chances (20-50 percent)
  for light snow are expected.

&&

.DISCUSSION...
Issued at 256 AM CST Fri Jan 31 2025

Low pressure to the south will tug slightly colder air southward
today with highs running about 10-15 degrees cooler than Thursday.
Even with this fairly significant drop in temperatures, highs will
still be a solid 10-15 degrees above normal, generally in the 40s.

A fast moving upper level ridge will move across the area this
afternoon and evening ahead of a fast moving wave that moves
through the Dakotas late tonight into Saturday. Analysis of model
soundings suggests that precipitation from this fast moving wave is
very unlikely. Saturation and forcing in the dendritic layer is not
too bad, but this layer is found roughly from 600-500 mb, with a
fairly significant dry layer below this. Some hints that we may see
a little stratus, but from about 650 mb to 900 mb it is very dry.
There is some very weak instability around the dendritic layer and
the dry layer is not quite as dry closer to highway 14 into
southwest MN, so maybe a sprinkle or very light shower. The overall
message is that Saturday will see quite a bit of cloud cover, but
very little precipitation.

As this system moves east, a strong jet and wave will move onto the
Western High Plains Sunday, which will drag colder air southward
Sunday afternoon and Sunday night. Precipitation with this initial
cold push Sunday afternoon and Sunday evening does not look very
likely. However Sunday night into Monday a wave will move out of
Wyoming and interact with the low and mid level thermal gradient
that is left behind by the earlier Sunday wave. Southerly flow will
develop ahead of this wave and bring a decent shot of forcing with a
good chance for a band of frontal precipitation. The low levels will
once again struggle a bit to saturate, but later Sunday night into
Monday morning the soundings are supportive of some snowfall. For
now the better chances appear to be near and north of I-90,
especially on the SD side. The latest EC Ensemble and GEFS 50th
percentile suggests a band of 1-2" of snow with the 75th percentile
more in line with 2-4". The GEFS is a bit farther north and closer
to highway 14.

Any snow the develops will likely be done by Monday afternoon, but
another system moves into the area Tuesday into Wednesday with only
marginal agreement on this energy. Will have some smaller chances
for snow during this time and take a wait and see approach to any
potential snow for mid to late week next week.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1031 PM CST Thu Jan 30 2025

Still watching the potential for MVFR to IFR stratus and patchy
MVFR to IFR fog tonight into early Friday morning, especially
for areas west of I-29 and along the Buffalo Ridge. For now,
have kept prevailing stratus to KHON where guidance has been
more persistent. Maintained SCT/FEW mention for KFSD/KSUX.
Confidence is low for a couple of reasons - uncertainty in lower
level moisture, winds, and incoming patchy cirrus clouds. If
stratus or fog can develop, expect improving conditions late
morning.

Northwesterly winds continue into Friday morning, with gusts
through the afternoon around 20 knots. Expect winds to shift
northeasterly by mid/late afternoon, and southeasterly by
Friday night.

&&

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

&&

$$

DISCUSSION...08
AVIATION...SG