509
FXUS63 KABR 041752 AAC
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1152 AM CST Sun Jan 4 2026

.KEY MESSAGES...

- Fog continues over the region today, especially over central SD
  where visibility may be reduced to around one-quarter mile or
  less during the morning hours.

- Patches of freezing drizzle or light freezing rain and sleet may
  affect portions of north central and northeast SD and west
  central MN today. This could lead to a few slick spots on
  roadways.

- Temperatures today into next week will be 10 to 20 degrees above
  normal.

&&

.UPDATE...
Issued at 1145 AM CST Sun Jan 4 2026

See below for an aviation forecast discussion for the 18Z TAFs.

UPDATE Issued at 1044 AM CST Sun Jan 4 2026

Surface obs, law enforcement feedback, webcams, road reports on
SD511.org and comments in Facebook, plus collaboration with
neighboring offices, has prompted the issuance of a winter weather
advisory across the northern tier counties of the CWA into this
afternoon. Plus, starting to see the "drizzle bloom" p-type
developing in the "northwest quadrant" of ABR`s WSR-88D. Soundings
depict a low stratus layer that is close, a little less than 1km
deep in some spots, a little more than 1km in others. There`s an
upper level shortwave moving overhead today. The synoptic-scale
UVV`s working through with this system could be enough to tip the
scales in the direction of freezing drizzle potential. Very little
in the way of measurable precipitation. Just enough to make roads,
sidewalks, bridges slippery. Plus, extended the dense fog advisory
over the central/north central forecast zones to 21Z this
afternoon, after canceling Buffalo, Lyman, Jones, Hughes and
Stanley counties. Those are the main changes to the today period
forecast. Updates are out.

UPDATE Issued at 533 AM CST Sun Jan 4 2026

Aviation discussion updated below for the 12Z TAFs.

&&

.SHORT TERM /TODAY THROUGH MONDAY AFTERNOON/...
Issued at 414 AM CST Sun Jan 4 2026

Stratus continues to cover the entire CWA, with fog over central SD.
Areas of fog across portions of northeast SD as well. Although
across central SD, many web cams reveal somewhat dense fog. Have
therefore issued a Dense Fog Advisory for areas west of the James
valley and will continue to monitor for areal coverage changes
throughout the morning. Some cams across central SD showing quite a
bit of frost accretion on surfaces. Cams over northeast SD reveal
pockets of flurries or perhaps even freezing drizzle. Will continue
to monitor this for potential addition into the grids/forecast.

For later today, models indicate only slow erosion of stratus into
central SD and perhaps across the fringes of the CWA bordering FSD.
Constructed sky grids to reflect cloudy/mostly cloudy wording for
much of the area east of the Missouri River, but especially for the
James valley and points east. Areas of fog may also linger even into
the daytime hours for eastern portions of the CWA. As low pressure
moves east today, there may be generation of light freezing
drizzle/drizzle, or even patches of light freezing rain or sleet
over far northeast SD into west central MN. Quite a large range of
forecast highs today from north (30s) to south (50s) as the low
pressure brings in some mild air to southern SD. Of course, cloud
cover will have a huge impact on highs, but where conditions clear
out over the southwest CWA, could see highs in the 50s along the I-
90 corridor.

Overnight, models indicate fog potential yet again so have inserted
this into the grids/forecast. As of now, best potential looks to be
over the eastern CWA. Looking ahead to Monday, conditions look dry
with rather mild temperatures. 30s and 40s for many areas, but may
be dealing with cloud cover once again.

&&

.LONG TERM /MONDAY EVENING THROUGH SATURDAY/...
Issued at 414 AM CST Sun Jan 4 2026

Zonal flow with a broad weak trough across the central CONUS slated
for late Monday into Tuesday, and presents with additional low
chances for moisture. There is actually a pair of weak shortwaves to
this, and while each comes with mid level moisture and ascent, we
are again faced with a period where saturation down to the surface
has to overcome a deep dry layer, with NAM BUFKIT profiles
indicating the loss of lift occurs before saturation. Thus, we`d be
left with mostly sprinkles. The warm layer dewpoint depression is
over 10C for the initial wave late Monday, with cooler temperatures
aloft but still around a 6C dewpoint depression for the second wave.

The next wave that follows through this weak trough pattern, with
split flow aloft, moves overhead late Wednesday.  Again, not much
for moisture with this system, with only a handful of ensembles
supporting measurable precipitation.

Focus shifts to late in the work week, as the upper trough overhead
deepens and shifts east. Still a lot of distance in placement
between the EC/GFS/Canadian of this trough, and as such the
associated low pressure system. The GFS placement of low(s) is
currently well to the east and suggests more of a split flow type
transition with a low to the north and south with little impact for
the CWA, the EC a bit farther west and more supportive of weather in
the CWA. None show significant run to run continuity at this point.
We can see likewise trends in ensembles with more precipitation in EC
members in comparison to GEFS/GEPS members. While its fun to point
out the one EC member with 15 inches of snow for Watertown, its also
important to note that only about 15% show an accumulation in excess
of 2 inches and about 40% an inch or less accumulation.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1145 AM CST Sun Jan 4 2026

Terminals KABR,KATY,KPIR,KMBG

IFR fog and low clouds over KPIR and KMBG (including some
intermittent light freezing drizzle potential over KMBG through
~19Z) are forecast to improve to VFR by 00Z, as northwest winds
develop and work to scour out the low level moisture and dissipate
the fog/low clouds.

KATY has just recently come out of IFR fog/stratus and is back
into VFR conditions right now. Guidance has KATY dropping back
into sub-VFR fog/stratus later tonight after 00Z.

IFR fog and low clouds over KABR (including some intermittent
light freezing drizzle potential through ~21Z) could burn
off/dissipate by 00Z. But, guidance has KABR remaining in a sub-
VFR state through, at least, 15Z Monday before conditions are
supposed to improve there.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Winter Weather Advisory until 3 PM CST this afternoon for
     SDZ006>008-011.

     Dense Fog Advisory until 3 PM CST /2 PM MST/ this afternoon for
     SDZ003>005-009-010-015>017-034-036-037.

     Winter Weather Advisory until 1 PM CST /noon MST/ this afternoon
     for SDZ003>005-009-010.

MN...Winter Weather Advisory until 3 PM CST this afternoon for MNZ039-
     046.

&&

$$

UPDATE...10
SHORT TERM...TMT
LONG TERM...07
AVIATION...10