044
FXUS63 KFSD 180002
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
602 PM CST Wed Dec 17 2025

.KEY MESSAGES...

- Strong south to southwest winds continue into this evening.
  Gusts to 50 mph are expected in the higher elevations of south
  central and east central South Dakota and southwest
  Minnesota.

- Strong cold front arrives Thursday morning bringing high winds
  and scattered snow showers. A High Wind Warning will be in
  effect along and west of a Sioux City to Worthington to
  Marshall line, with a Wind Advisory to the east. Gusts of 55
  to 60 mph expected with isolated gusts to 70 mph in the
  warning.

- Potential for snow squalls continues Thursday morning, with
  impacts to visibility/travel possible into the afternoon due
  to continuing scattered snow showers. Where roads are still
  wet from tonight`s rain, flash freeze conditions are possible
  as temperatures quickly fall below freezing.

- Mild temperatures and mostly dry conditions are expected into
  next weekend and the first portions of Christmas week.

&&

.DISCUSSION...
Issued at 228 PM CST Wed Dec 17 2025

BLUF: Focus for this forecast remains on the next 24-30 hours with a
strengthening low pressure system and strong cold front expected to
move through the area. This system will bring rain this evening into
tonight, followed by snow showers overnight and through the day
Thursday. Very strong winds are expected through tomorrow night as
well. Impacts include: possible flash freeze tonight/early Thursday
morning with tanking temperatures; reduced visibility and hazardous
to difficult travel due to falling snow; hazardous to difficult
travel, possible power outages and tree damage due to strong winds.

THROUGH TONIGHT: Low pressure continues to deepen over the northern
Rockies. Elevated cold front and initial mid level wave are
currently over the western Dakotas, which continue to move east
tonight. Southerly winds are strengthening this afternoon with the
strongest winds in the higher elevations of the Buffalo Ridge and
across south central SD. Through 2 PM, sustained winds are up to 30
mph with gusts to 40 mph. Winds should continue to strengthen over
the next few hours, with gusts to 50 mph. Wind Advisory through this
evening for these locations remains in good shape, so did not make
any changes.

Clouds continue to increase ahead of the wave, which brings rain to
the area this evening through tonight. Rain moves from west to east,
and should exit our northwestern IA counties by 4 AM CST or so.
Rainfall amounts generally a tenth to maybe a quarter of an inch.
Temperatures fall from the 30s to even lower 40s late this evening
to the lower/mid 30s by 6 AM Thursday as the 850mb cold front and
first push of CAA move through the region. Tanking temperatures may
lead to a flash freeze of any moisture on roads/other surfaces
through the early morning hours. Finally, light snow showers move
into central SD and the northern James River Valley by early
Thursday morning with the next push of vorticity and the surface
front.

THURSDAY: As previously mentioned, concern remains for the flash
freeze potential due to overnight rain and plummeting temperatures
through Thursday morning. By noon tomorrow, most places will have
fallen into the teens and lower 20s. Flash freeze, if it occurs,
could lead to hazardous to difficult travel.

Although some locations were breezy today, more widespread and
stronger winds are expected beginning Thursday morning through the
night. Low pressure deepens and LLJ strengthens. We`ll mix down
these stronger winds. As was mentioned in the previous discussion,
RAP and HRRR soundings briefly show 65+ knots at the top of the
mixed layer Thursday morning into the early afternoon. Not expecting
that strong of winds to mix down, but widespread 50-65 mph wind
gusts are expected. Strongest winds will be in the higher elevations
of southwestern MN to the I-29 corridor and west. Would not be
surprised to see gusts to 70+ mph across south central SD. Winds
taper down through the evening and night. Did not make any changes
to the already issued High Wind Warning and Wind Advisory. Not
expecting any lingering snow pack to blow around (thanks to our
warm temperatures and rain), but any falling snow will blow around.

Finally, scattered snow showers are expected to move through the
area in two rounds - one during the earlier morning hours and the
second moving across the forecast area during the morning rush and
into the early afternoon - both associated with some PVA and CAA.
Snow squalls are possible with both rounds of snow showers with
strong low level frontogenesis and instability around 50 J/kg. Snow
showers and squalls will lead to visibility below 1/2 mile at times.
HREF does show moderate (up to 60%) chances of visibility below 1/2
mile on the western edge of the Coteau de Prairies through the late
morning hours. Given the anticipated scattered and convective nature
of snow squalls, held off on any Winter Headlines for the time
being. Accumulations of less than an inch expected.

In summary, hazardous to difficult travel conditions prevail on
Thursday into Thursday evening due to strong winds and snow showers.
Prepare for falling temperatures, a potential flash freeze, and
strong winds now. If traveling, be aware of quickly changing
conditions and drive to weather and road conditions. Secure loose
objects and holiday decorations.

FRIDAY ONWARD: Northwesterly flow aloft on Friday shifts to quasi
zonal flow for the weekend and into next week. A couple of waves
moving through Friday and again Saturday may bring some light
precipitation to the region, but confidence is low on any impacts
given low chances for measurable precipitation. With prevailing
quasi zonal flow through much of next week, temperatures should
generally remain above normal with some fluctuations in how much
above normal. Periodically breezy conditions are expected along with
continued very low precipitation chances.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 602 PM CST Wed Dec 17 2025

VFR conditions are expected to prevail outside a line of light rain
showers that are currently making their way east across the region.
Brief reductions in ceiling and visibility to MVFR are possible.

Strong southerly winds are gusting 25-35 kts with gusts to 40 kts
possible. Areas at elevation over the Coteau de Prairie and areas of
south central South Dakota are experiencing higher gusts up to 45
kts. Winds will begin to turn westerly around midnight and relax
somewhat to 20-30 kts. The break is short lived as a cold front
begins to move through the region after 18.09Z. Winds become
northwest and increase. Frequent gusts of 40-50 kts are expected
with isolated gusts up 55 kts in south central South Dakota. Very
strong winds begin to taper off slowly in the late afternoon
Thursday.

In addition, LLWS shear will be problematic through portions of the
period at all three TAF sites. Speed shear of 50-60 kts will be
common across the region through about midnight. Then a brief pause
as winds calm slights and change from southerly to
northwesterly. Then increase again to 45-55kts of LLWS through
about day break.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...High Wind Warning from 6 AM to 6 PM CST Thursday for SDZ039-
     040-054>056-060>062-065>071.
     Wind Advisory until 9 PM CST this evening for SDZ040-050-057-
     063.
     High Wind Warning from 3 AM to 6 PM CST Thursday for SDZ038-
     050-052-053-057>059-063-064.
MN...High Wind Warning from 9 AM to 6 PM CST Thursday for MNZ071-
     072-080-089-097-098.
     Wind Advisory from 9 AM to 6 PM CST Thursday for MNZ081-090.
     Wind Advisory until 9 PM CST this evening for MNZ071-072-080-
     081-090.
IA...High Wind Warning from 9 AM to 6 PM CST Thursday for IAZ001-
     012.
     Wind Advisory from 9 AM to 6 PM CST Thursday for IAZ002-003-
     013-014-021-022-032.
     High Wind Warning from 6 AM to 6 PM CST Thursday for IAZ020-
     031.
NE...High Wind Warning from 6 AM to 6 PM CST Thursday for NEZ013-
     014.

&&

$$

DISCUSSION...SG
AVIATION...AJP