869
FXUS63 KFSD 250915
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
315 AM CST Mon Nov 25 2024

.KEY MESSAGES...

- Below to well below normal temperatures will continue into
  the holiday weekend with highs expected to drop below freezing
  from Thanksgiving day onwards.

- Low confidence light snow chances (10%-20%) return on
  Wednesday and again from Friday night into Saturday. Those
  with distant travel plans for Thanksgiving should continue to
  monitor the forecast.

- Sub-zero wind chills will return to the region each night
  from Thursday night onwards.

&&

.DISCUSSION...
Issued at 310 AM CST Mon Nov 25 2024

TODAY & TONIGHT: A cooler and breezier day is ahead! Taking a
look across the area, areas of flurries to light snow continue
to push across areas east of I-29 this morning with the better
coverage centered over portions of northwestern IA. Expect these
developing areas of precipitation to push out of our area
closer to 12z this morning with accumulations up to a tenth or
two possible. From here, cloud cover will gradually decrease as
a strong shot of cold air advection (CAA) moves through the
region with the base of the mid- level trough. With this in
place aloft and breezy northwesterly at the surface, expect
chillier conditions throughout the day as highs peaking in the
mid 20s to low 30s for the day. Looking into tonight, the cool
and quiet conditions will continue as surface ridging move
across the area. As surface winds gradually decrease and
eventually decouple overnight, expect the cooler air to make its
way to the surface as overnight lows decrease into the low
double digits to teens for the night.

TUESDAY-THURSDAY: Heading into the extended period, quieter
conditions will continue into Tuesday as quasi-zonal flow
returns aloft. As the warmer part of the mid-level ridge moves
across our area, warm air advection (WAA) will strengthen
leading to a temporary increase in our temperatures for the day.
With this in mind, expect daily highs to peak out in the low
30s to mid 40s for the day with the more mild conditions
expected along and south of I- 90. By Tuesday night, cloud cover
will gradually increase from south to north as a quick
shortwave swings across the Dakotas with its surface cold front
into Wednesday potentially bringing our next light snow chances
(10%-20%). However, with 25.00z deterministic guidance
continuing to back off on any significant chances; any
developing snow will likely be isolated to areas north of I-90
as the base of the mid-level wave swings across northeastern
South Dakota and southern Minnesota.

Any accumulations are expected to light at best with most
ensemble guidance only showing low to medium confidence
(30%-40%) in a trace of snow. From here, expect any lingering
snow chances to push out of our area by Wednesday night as
quieter conditions return once again. Looking into Thanksgiving
Day, colder air will continue to funnel into the region behind
the departed cold front decreasing our 925 mb temperatures
further into the -8 to -12 degree C range aloft. This in
combination with marginally breezy northwesterly surface winds
with gusts up to 25 mph will lead to chillier conditions overall
as highs only peak in the low 20s to low 30s across the area.
From here, expect the chilly condition to extend into the
overnight hours as lingering cold air advection (CAA) and
northwesterly surface flow leads to overnight lows in the single
digits with the coldest conditions along the Hwy-14 corridor.
Lastly, the combination of elevated surface winds and colder
temperatures overnight will lead to even colder wind chills in
the negative single digit to low double digit range by Friday
morning.

THE WEEKEND: Looking into the weekend, an active pattern aloft
will promote a cooling trend into the start of December. With
northwesterly flow aloft, multiple waves will move through the
region over the holiday weekend. The strongest of which will
swing through by Friday night into Saturday as a quick clipper
ejects out of the Rockies. While some light snow chances
(10%-20%) remains possible across the area, variability among
long-range guidance has made it difficult to say with any
confidence this time. With this in mind, left the default NBM
POPs in for this time period. If you are traveling for the
holiday weekend, make sure to monitor your local forecast for
changes! Otherwise, temperatures will continue to decrease
throughout the weekend as daily highs peak in the teens to low
20s with overnight lows in the positive to negative single
digits across the area. The cold temperatures in combination
with periodic breeziness will lead to even colder wind chills in
the negative single digits to teens each night through Sunday
night with coldest values expected by Saturday night.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1030 PM CST Sun Nov 24 2024

MVFR and IFR ceilings will decrease from west to east through
the late night hours into early Monday morning. At the same
time, light snow or patchy drizzle (over northwestern IA) will
also diminish by 08Z. Winds will continue out of the northwest,
gusting around 25 kts into late Monday afternoon. Winds then
become light on Monday evening.

&&

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

&&

$$

DISCUSSION...Gumbs
AVIATION...JM