004
FXUS63 KABR 110259 AAB
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
859 PM CST Wed Dec 10 2025

.KEY MESSAGES...

- Wintry mix of snow, sleet, and freezing rain expected across
  portions of mainly central South Dakota overnight through early
  Thursday evening. Ice accumulation of a tenth to a quarter of an
  inch possible, with locally higher amounts over north central
  South Dakota. Snow accumulation will generally be around 2
  inches or less.

- Highs Friday and Saturday will be in the single digits to teens,
  coldest Sunday morning. Wind chill values Saturday and Sunday
  morning could be as low as -20F to -30F degrees.

- For Friday night through midday Saturday, there is a 30 to 50% chance
  of 2" of snow or more between I-90 and areas southwest of a
  line from Eureka to Aberdeen through Watertown and Clear Lake.

&&

.UPDATE...
Issued at 854 PM CST Wed Dec 10 2025

Radar showing echoes aloft across the western CWA, but still not
seeing any evidence of snow reaching the surface after looking at
obs/web cams across the region. RAP/HRRR soundings indicate full
saturation from now through midnight, although some of the latest
hi-res guidance showing precip holding off until closer to
morning. May make some adjustments to PoPs to better reflect this.
Also, with the abundance of cloud cover, raised lows a few
degrees across the CWA. Otherwise, still looking at icing
potential to develop over central SD by Thursday morning. No
changes to headlines at this time.

&&

.DISCUSSION...
Issued at 348 PM CST Wed Dec 10 2025

Ice, snow, and cold will be the themes and main concerns through
Sunday, with warmer air returning early next week.

The surface temperature forecast has changed little since the last
update, staying in the single digits to low 20s tonight, and rising
into the upper teens to near 40 degrees Thursday (warmest over south
central SD). However, temperatures above the surface have changed in
such a way to push the freezing rain/snow line slightly to the
southwest - mainly southwest of a line from around Aberdeen to
Andover and Watertown to Clear Lake. More sleet in the forecast is
also acting to reduce overall freezing rain amounts near and
northeast of a line from Aberdeen to Watertown. This is a very
tricky forecast, with the difference of a degree or 2 changing what
type of precipitation lands at the surface.

The range for forecast precipitation is also large giving us low
confidence in specific amounts of rain, snow, or sleet with this
event. Some of the largest differences were noted at Mobridge. A
swath of higher precipitation is expected somewhere over north
central/central to southeastern SD. The deterministic model runs
have consistently been on the higher end for precipitation, with the
CAMs being on the low end. Given the overall trend to highlight
Corson County in the area of higher end precipitation, it has been
upgraded to an Ice Warning. Elsewhere, given the only moderate
confidence of receiving 0.25" or more of ice accumulations, the
headline was kept at a Winter Weather Advisory. Jones and Lyman were
added, and the overall timing was pushed back about 3 hours for the
start times on most of the headlines. While precipitation will start
at or by 00Z over much of central SD, the main concern (freezing
rain) looks to hold off until closer to 06Z. The warmer air moving
into portions of central South Dakota (Jones/Lyman Counties more
than any other) in the afternoon will slowly transition
precipitation to mainly rain, with pockets of freezing rain and snow
continuing through the afternoon.

The highest snowfall amounts during the day Thursday of around 1 to
less than 2 inches is expected northeast of a line from Aberdeen to
Clark. South of a line from Aberdeen to Watertown and Clark, ice
accumulations of around one tenth and two tenths of an inch are
expected, with locally higher amounts.

Increased winds Thursday afternoon through Thursday night with the
cold air advection moving in, with the largest changes Thursday
afternoon into the early evening hours over central SD. The
strongest winds, with gusts nearing 30kts over north central SD
around 06Z Friday will expand to much of the rest of the forecast
are (and particularly the Prairie Coteau) by daybreak Friday.

Friday night through midday Saturday, there is a 30 to 50% chance of
2" of snow or more between I-90 and southwest of a line from Eureka
to Aberdeen through Watertown and Clear Lake (and a 70% chance of
precipitation as a whole over central SD).

It looks like we`ll finally get a break from the precipitation every
12-24 hours starting Saturday night and continuing through Tuesday
night. Even Wednesday of next week looks mainly dry at this point,
with a 15-20% chance of light precipitation (rain or snow) over our
north to northeastern counties.

Otherwise, Friday through Sunday still look cold, with the lowest
temperatures in the 0 to -22F range Sunday morning (coldest east of
the MO River) - with pockets of -30F wind chill values.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 540 PM CST Wed Dec 10 2025

Terminals KABR,KATY,KPIR,KMBG

MVFR CIGs continue to affect KABR/KATY at the start of the TAF
period, with uncertainty if they`ll improve to VFR before the next
system moves in tonight/Thursday with a return to MVFR/IFR CIGs.
Across central SD, CIGs will lower to MVFR/IFR overnight with the
arrival of -SN/SN and MVFR/IFR VSBY. Mixed precipitation in the
form of -FZRA/FZRA (freezing rain) or even PL (sleet) is expected
across central SD also, even as far east as KABR/KATY, but with
lower confidence. A period of low-level wind shear (LLWS) is also
forecast across KPIR late morning on Thursday.


&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Ice Storm Warning until 5 PM MST Thursday for SDZ003.

     Winter Weather Advisory from midnight tonight to 6 PM CST
     Thursday for SDZ004-009-010-016-017-034>037-051.

     Winter Weather Advisory from 3 AM to 6 PM CST Thursday for
     SDZ005-006-018.

     Winter Weather Advisory from 6 AM to 6 PM CST Thursday for
     SDZ011-019>023.

     Winter Weather Advisory from midnight CST /11 PM MST/ tonight to
     3 PM CST /2 PM MST/ Thursday for SDZ015-033-045-048.

MN...None.
&&

$$

UPDATE...TMT
DISCUSSION...06
AVIATION...TMT