664
FXUS63 KABR 081147 AAA
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
547 AM CST Mon Dec 8 2025

.KEY MESSAGES...

- Areas of fog, some of it locally dense reducing visibility to
  one quarter mile or less, will persist throughout and east of
  the Missouri River valley this morning.

- Potential for Sisseton hills downslope winds (35 to 50 mph) and
  perhaps blowing snow issues this afternoon prior to temperatures
  warming to near the freezing mark.

- Next clipper will most likely (60-90% chance of occurrence) be
  preceded by a period of light freezing rain Tuesday morning
  before temperatures return to above freezing Tuesday afternoon
  across northeast SD/western MN.

- Northwest winds Tuesday afternoon and evening could gust in
  excess of 50 to 60 mph across central and north central South
  Dakota. 45 to 55 mph gusts for the northeast Tuesday
  evening/overnight.

- By the end of the week, colder air is expected to move in. High
  temperatures will be near to just above 0 degrees, with
  overnight lows as low as the teens below zero. Wind chill values
  Friday and Saturday morning could be as low as -20 to -30
  degrees.

&&

.UPDATE...
Issued at 539 AM CST Mon Dec 8 2025

Issued a Dense Fog Advisory for portions of central and north
central South Dakota for this morning, per regional webcams and
surface obs revealing dense fog over the area. Also, see below for
an aviation forecast discussion for the 12Z TAFs.

&&

.SHORT TERM /TODAY THROUGH TUESDAY AFTERNOON/...
Issued at 353 AM CST Mon Dec 8 2025

At 3 AM CST, skies are cloudy and there is fog over portions of
central and north central South Dakota. Some areas are noted
reporting visibility below 1SM. Temperatures are holding in the
single digits above to teens above zero on south-southeast winds
around 5 to 15 mph.

Low level WAA is happening and will continue to occur through the
end of the day today, as a clipper system works across North Dakota
into Minnesota, dragging a warm front through the CWA. Winds will
respond by switching from southerly to westerly before the day is
over. Still anticipating a downslope wind event on/east of the lee-
of-the-Prairie Coteau over far northeast South Dakota. Maintained
inherited "areas of blowing snow" mention for this afternoon, where
strongest sustained winds and gusts are expected to loft and blow
the 2+ inches of fluff that has fallen in that region over the past
couple of days prior to temperatures this afternoon potentially
warming up enough to begin the melting process of snow on the
ground. And, will have to see how impactful melting snow could
become once temperatures cool back down below freezing tonight,
potentially causing "blow ice" conditions on area roads.

The cold front on today`s clipper low to the north may be able to
backdoor its way into the far northeastern forecast zones overnight,
which could result in low temperatures over that area being a few
degrees colder than the rest of the CWA. Heading into Tuesday
morning, the strongest clipper low of the week will be descending on
the region. WAA-forced precipitation could be spreading into north
central South Dakota as early as 3 AM CST Tuesday, with freezing
rain potential spreading over into west central Minnesota through
late Tuesday morning. Warmer than freezing surface temperatures in
rain potential should be chasing these colder than freezing surface
temperatures in rain potential from west to east throughout the
morning on Tuesday, with any lingering freezing rain potential over
west central Minnesota pretty much done and gone by noon CST
Tuesday. A Winter Weather Advisory for freezing rain may end up
being needed for a few hours from early Tuesday morning across north
central/northeast South Dakota to late Tuesday morning into west
central Minnesota, prior to plain rain potential taking over on
Tuesday.

The reinforcing shot of low level warmth on westerly winds Tuesday
will make two days in a row where meaningful snowmelt (crusting of
snow) will be able to happen across central/north central South
Dakota (and over into portions of northeast South Dakota, too) prior
to this clipper system`s cold front slamming into the state, turning
winds out of the northwest and increasing them potentially to as
much as 30 to 45 mph with gusts in excess of 60 mph. ENS EFI/shift-
of-tails is still bulls-eyeing the CWA for some strong winds
Tuesday/Tuesday night. Plus, 0.5km wind progs, pressure tendency
progs, pressure gradient, and low level CAA Tuesday afternoon and
beyond support the High Wind Watch that remains in effect for
central and north central South Dakota for Tuesday afternoon through
late Tuesday night.

&&

.LONG TERM /TUESDAY EVENING THROUGH SUNDAY/...
Issued at 353 AM CST Mon Dec 8 2025

Through the long-term period, the overall upper-level pattern of a
longwave trough over the eastern CONUS  coupled with a longwave
ridge over the western CONUS, placing the Aberdeen forecast area in
the transition zone in between. As such, a couple of jet streaks are
expected to move overhead mid to late this week, bringing further
snow chances and colder air.

When the period opens Tuesday night into early Wednesday morning,
strong winds on the back side of a low pressure center to the east
will continue to impact the forecast area. Winds will taper off as
the night progresses, but gusts upwards of 40 miles per hour will be
possible through Wednesday morning. A High Wind Watch remains in
effect through 09Z Wednesday morning.

The next chances for precipitation come Wednesday night into
Thursday as a jet streak moves overhead. Model soundings indicate
that snow is the most likely precip type for most of the CWA, but it
will be dependent upon near-surface temperatures. A temperature
gradient is expected across the CWA, with highs in the teens over
northeastern South Dakota and western Minnesota, ranging to above
freezing over parts of central South Dakota. The latter portion of
the forecast area may see freezing rain, rain, or a wintry mix
depending on where the freezing line sets up as well as how warm
temperatures get. For areas seeing snow, up to two inches of
accumulation will be possible.

Strong northwesterly flow aloft will continue through the end of the
week, continuing to cool the profile. By the end of the week,
temperatures will be 20-25 degrees below normal for mid December.
Highs Friday and Saturday are expected to be in the single digits
across most of the forecast area, with overnight lows as low as -10
to -15 degrees. With temperatures that cold, it won`t take much wind
to significantly drop wind chills in the early morning hours. Long
range ensemble probabilities indicate that apparent temperatures
will approach Cold Weather Advisory criteria in parts of northern
South Dakota and western Minnesota. Probability of -30 degree wind
chills in those areas Friday morning is around 20-40%, with Saturday
staying a bit lower at around 10-20%. Trends will continue to be
monitored for a potential headline, but no action is necessary at
this time.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 539 AM CST Mon Dec 8 2025

Terminals KABR,KATY,KPIR,KMBG

Sub-VFR stratus/fog over KPIR/KMBG will gradually improve through
late this morning. VFR conditions are expected to prevail at
these two terminals after 18Z today. Sub-VFR stratus over
KABR/KATY is also expected to improve by early this afternoon. The
fog over central South Dakota may advect over into northeast
South Dakota through late this morning. Will keep a close eye out
on this potential development. VFR conditions are expected to
prevail at KABR/KATY by 21Z this afternoon. South winds at or
under 15 knots are expected to become westerly this afternoon,
potentially increasing to 15 to 20 knots with gusts to 25 kts.
There could also be a few hours of low level wind shear impacting
KPIR, KABR and KATY by early this evening.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...High Wind Watch from Tuesday afternoon through late Tuesday
     night for SDZ003>005-009-010-015>017-033>037-045-048-051.

     Dense Fog Advisory until 11 AM CST /10 AM MST/ this morning for
     SDZ004-005-009-010-015>017-034>036-048-051.

MN...None.
&&

$$

UPDATE...10
SHORT TERM...10
LONG TERM...BC
AVIATION...10