996
FXUS63 KFSD 180807
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
207 AM CST Thu Dec 18 2025

.KEY MESSAGES...

- Northwest winds barrel through the area this morning with
  gusts of 50 to possibly 70 mph. The strongest winds are most
  likely near and west of the James River.

- While the existing snow pack is too wet to blow, some falling
  snow will bring the potential for rapid drops in visibility
  when combined with the very strong winds. These possible snow
  squalls will be most likely from about 9 am to 1 pm and most
  likely near and north of I-90.

- Falling temperatures into the teens and lower 20s this
  morning will likely cause wet roads to flash freeze. This may
  cause somewhat unpredictable icy driving with the rapid drop
  in temperatures.

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

&&

.DISCUSSION...
Issued at 206 AM CST Thu Dec 18 2025

The latest water vapor shows a potent wave in western ND which will
dive southeast through and strengthen this morning, bringing a rapid
change in weather to the area. While strong winds of 50 to 70 mph
are expected, what is more difficult to determine will be the
impacts of any snow that falls within the core of the vort max aloft
from roughly mid morning into early afternoon. The latest models do
show some instability within the core of this vort max and when
coupled with the vertical column of temperatures rapidly falling
into the DGZ, bands of snow will be likely. With wind gusts of 50 to
70 mph, any snow that falls will result in rapid, short term
reductions in the visibility and could result in snow squalls for
the area. At this time the better chances for these rapid reductions
in visibility will be most likely near and north of I-90 from mid
morning through early afternoon.

Timing of this forcing from the vort max/elevated instability and
the potential for snow squalls will be from central SD towards the
James Valley from about 14-16z, from the James Valley towards I-29
from about 16z-18z and into southwest MN and parts of northwest IA
from 18z-21z.

Quick upper level ridging moves through tonight bringing a quick
decrease in winds, which will then turn more southerly later tonight
into Friday. This will bring a chance for precipitation but these
chances will be mainly north of the area. What this next wave brings
is more wind, albeit not nearly as strong as today. Southerly winds
will likely gust to 30-35 mph on Friday, then a front will move
through Friday night and bring the chance for 30-35 mph gusts Friday
night into Saturday. Precipitation is not expected with this front
either.

Saturday and Sunday will see broad upper level ridging build in
which should bring dry and seasonal temperatures. Westerly flow
aloft increases a bit by Monday which will bring another round of
very mild temperatures, likely widespread highs in the 40s and 50s.

Tuesday through Thursday may see a few ups and downs with
temperatures but overall little chance for precipitation and near to
above normal temperatures are expected. With diminishing snowpack,
temperatures may end up milder than forecast given some of the
expected 925-850 mb forecast temperatures.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1134 PM CST Wed Dec 17 2025

VFR conditions are expected to prevail outside of light rain showers
that are currently making their way east across the region. Brief
reductions in ceiling and visibility to MVFR and IFR are
possible. Rain pushes east of the region around daybreak. Also
around daybreak light snow begins to move into the region from
central South Dakota. While snow will be light, strong winds
coupled with falling snow will likely result in reductions to
visibility at times. Light snow showers continue to move east
through most of today.

Winds have begin to turn to the northwest and increase as a
cold front begins to move through the region. Frequent gusts of
40-50 kts are expected with isolated gusts up to 55 kts in south
central South Dakota. Very strong winds begin to taper off
slowly in the afternoon today.

In addition, LLWS shear will be problematic through the first
portion of the period at all three TAF sites. Speed shear of 45-55
kts will be common across the region the early morning.

&&

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

&&

$$

DISCUSSION...08
AVIATION...AJP