866
FXUS63 KABR 292312 AAA
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
512 PM CST Mon Dec 29 2025

.KEY MESSAGES...

- Downslope winds of 25 to 30 mph tonight into Tuesday morning
  may produce drifting snow along the eastern side of the Sisseton
  Hills. At this time, the snow is not expected to be lofted high
  enough to reduce visibilities.

- There is a 40% chance of snow Wednesday morning over northeast
  SD and west central MN. Snow accumulations are expected to be
  less than an inch.

&&

.UPDATE...
Issued at 509 PM CST Mon Dec 29 2025

The forecast remains on track this evening. No major changes are
planned.

&&

.DISCUSSION...
Issued at 1242 PM CST Mon Dec 29 2025

High pressure currently over southeastern SD has created a sunny sky
across the area today. But even with that sunshine, the cold air
that surged in yesterday is still keeping temperatures cold, with
mid-day temps in the single digits above zero over northeast SD and
in the mid teens towards Pierre. Those clear skies will be short
lived, as there is an area of mid clouds dropping to the southeast
across the northeastern two thirds of ND and will be moving into SD
and west-central MN later this afternoon and through the evening
hours. This is ahead of the first of two weak clipper systems moving
through the region over the next couple of days.

Before getting into the clippers, did want to mention that there
will likely be a weak downslope wind event on the east side of the
Coteau tonight into Tuesday morning. Overall, it`s not the best
direction for winds (more westerly instead of southwesterly), but
could see some enhancement in the winds and gusts getting up into
the 25-30kt range. With the fresh snow in this area, that does bring
up some concerns for blowing/drifting snow. This will depend on the
sustained winds and with the age of the snow pack, we`ll need
sustained winds over 25kts to start seeing larger areas of lofted
snow to reduce visibility. Right now, that`s not expected and will
continue to message the drifting snow (snow not being lofted more
than a couple feet off the ground). As temperatures warm into
Tuesday and towards freezing, that could lead to some roads becoming
icy where drifting snow occurs.

Now for the clippers. The current northwesterly flow aloft will be
fairly consistent over the next 5-7 days with a ridge over the west
and a trough over the eastern CONUS. This will bring a couple
clippers/shortwaves through the upper midwest on Tuesday and
Wednesday. The first clipper will track from Winnipeg and through
northern MN, putting the northeast edge of our CWA on the southwest
side of the precipitation area. At this time, only highlighted a
slight chance (15%) for snow over Traverse county for tomorrow
morning. EC-Ens seems less enthused about the warm nose into west-
central MN on Tuesday morning (less than 25% of members have warm
nose above 0C) and the P-Type meteograms show a sub 5% chance of a
mix. Thus, have left as snow for now, but will need to monitor for
any potential mix, especially if the precip ends up being a little
farther to the southwest than currently expected.

After this initial wave, we might see a brief clearing, then
additional clouds move in ahead of the next clipper. With that
shallow moisture, models are showing hints of light QPF Tuesday
night in far northeast SD and west-central MN (more so in eastern ND
and into central MN), which could also be a concern for mixed precip
due to the dry air above -10C and limited ice present. Then the next
clipper (weak 1016mb low tracking through western/central SD)
arrives on Wednesday morning and continues into the first part of
the afternoon. Best opportunity for snow appears to be over eastern
ND and into northwestern and central MN with the northwest to
southeast track. Forcing for this event will be associated with a
narrow area of 925-850mb FGen. That of course leads to some
uncertainty on the track of the band, but models do seem to be
fairly consistent in this band being strongest in eastern ND and
then brushing the far northeast part of SD and into west-central MN.
NBM 25th-75th percentile snowfall amounts still show values being
light (0-1"), mainly to the northeast of a line from Britton to
Clear Lake. Winds still look to be light enough to not lead to any
blowing/drifting issues.

For the rest of the period, no significant precipitation chances at
this point. Temps will settle back closer to normal for the new year
(although plenty of spread in the NBM 25th-75th percentile highs).
With the northwest flow aloft, the coldest temps will be in
northeast SD and warmest over the southwest. Finally, there are some
hints of a stronger shortwave rounding the western ridge and moving
through the region for the second half of the weekend. Right now, it
appears any precip chances will remain to the north of the area and
over northern ND/MN and southern Canada.

By 00Z Wednesday we`ll be in between systems. Warmer air with 850mb
temperatures of 0 to 4C will remain over central SD, with 0 to -7C
degree air over northeastern SD and west central MN (lowest over
MN). The contrast becomes greatest by late morning Wednesday, with
surface temperatures showing the contrast with highs near 40 in
Jones County, while in the teens over west central MN.

While flurries or very light precipitation will be possible Tuesday
morning over our far northeastern counties (showing up on a couple
of CAMs), the next chance of measurable precipitation looks to hold
out until mainly Wednesday morning over northeastern SD and west
central MN, in the form of a 40% chance of light snow. Snow to
liquid ratios will be around 10-15:1. With a banded look, it will be
difficult to pin point the exact location of highest
precipitation/snowfall, but at this time it looks to focus on our
west central MN counties with around 1" or less snow. There is
around a 30-40% chance of 1" or more snow over that location, and a
15% chance of 2" or more snow. One thing we`ll need to monitor is
the potential for a wintry mix (freezing drizzle) from around 00-12Z
Wednesday, as noted on the 12Z ENS precipitation type meteograms and
backed by plenty of low level moisture below 800mb. It looks like
snow is most likely, with most of the precipitation from 12-18Z.

Much of the rest of the forecast remains dry with temperatures
moderating back into the 20s and 30s by Friday or Saturday and
continuing through the weekend. Confidence in specific temperatures
remains only moderate at this time given the average 10 degree
spread in the NBM 25th-75th ranges starting Wednesday and continuing
through the period.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 509 PM CST Mon Dec 29 2025

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are expected through Tuesday morning. MVFR cigs
will move into KATY after 21z.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&

$$

UPDATE...20
DISCUSSION...SRF
AVIATION...20