512
FXUS63 KABR 091543 AAB
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1043 AM CDT Mon Mar 9 2026

.KEY MESSAGES...

- A band of snow sets up along the ND/SD state line this evening.
  Overall accumulations for the area should be light, but a
  localized narrow ribbon of 2 to 4 inches accumulation is not out
  of the question.

- Another system for Tuesday/Tuesday night has the potential to
  bring inch or two to mainly central and eastern SD.

- A clipper Thursday will be associated with mainly strong winds,
  though confidence is not high enough at this time for specific
  ranges.

&&

.UPDATE...
Issued at 1031 AM CDT Mon Mar 9 2026

Not many updates needed to the forecast through 00Z today. Will be
cooler across the region behind last night`s passing cold front.
Mainly 40s and 50s for highs, with readings close to 60 along I-90
across Jones/Lyman counties. Will be watching arrival of this
afternoon/tonight`s storm system, with rain/snow mix potentially
moving into north central SD by late afternoon, although it still
appears most of the precip with this system will be overnight.
More on that in this afternoon`s discussion.

&&

.DISCUSSION...
Issued at 301 AM CDT Mon Mar 9 2026

Frontal boundary moving south across the state this morning, gusts
have diminished in its wake so have lowered wind potential this
morning. Behind the front is somewhat cooler air, especially in
comparison to Sunday`s record warmth. NBM is still running about 5
to 15 degrees above normal, and current temperatures are close to
forecast highs so will continue to stick with the NBM.

Still looking at a band or bands of snow associated with a really
tight mid level baroclinic zone. Placement is the main issue with
the NAM showing a pair moving across southeast North Dakota and
northeast South Dakota, the GFS/Canadian shows more of a single
band. Peak precipitation totals within this feature range around 0.2
inches, though the ARW is closer to a 0.3 inch peak around the
Sisseton area.  We can also see in the Caribou tool that snow ratios
jump well past the NBM 10:1 up into the teens to around to 20:1
during peak intensity, which matches the NAM BUFKIT depiction with
20 microbars at 550mb (the core of the dendritic growth zone) for
about a 1 hour span. Thus, there could be a very localized heavier
burst and 2-4 inches accumulation with this band. Unfortunately NBM
probables smooth it out and only have a 20-40% chance for exceeding
1".

The mid level baroclinic zone shifts south for Tuesday and becomes
the focus for additional snowfall Tuesday night, this on a bit
farther south (central to east central SD). GFS/EC/Canadian all have
an additional 0.1" liquid equivalent, though the latest NAM barely
even registers this feature. With broader precipitation (not a
banded feature) confidence is a little better with the NBM
probability of exceeding 1" closer to 30-50% from Pierre to
Watertown.

That system departs, with a weak high pressure sandwiched between
the one to the east and a clipper gaining steam in northwest
Montana. This system comes through Thursday into Thursday night. The
EC trend is a little farther south in comparison to yesterday, while
the GFS has only shifted southwards a few tens of miles and still
maintains a 989mb low. The end of the NAM run is similar to the GFS
in location and intensity while the Canadian is much weaker. Main
take-aways for this clipper is going to be the winds with the track
mainly north of the CWA, lest we trend towards the EC. The GFS puts
us in more of a warm advection transient north south band (moving
east/northeast) followed by wrap around, which overall will limit
QPF potential. Additionally, the mild air that wraps into the system
will limit any snow to the backside of the system and quite a bit of
that will depend on how rapidly the airmass cools, something that
isn`t quite addressable at this time given the range of outcomes
from guidance, though it should be noted that NBM probability of
exceeding just a dusting (0.1) only tops out at about 30-40% along
the ND/SD state line and in the higher elevations of the Sisseton
hills.

The arctic front continues to meander across the state late week and
for the weekend meaning continued chilly temperatures. In fact,
Sunday/Monday, NBM highs are only in the 20s, 10 to 20 degrees below
climatology. It should be noted at these timescales, the NBM range
between the lower/upper bounds is out to 10 to 15 degrees, but even
at the 90th percentiles - this would mean highs in the low 30s to
low 40s from northeast to southwest.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 639 AM CDT Mon Mar 9 2026

Terminals KABR,KATY,KPIR,KMBG

Mainly VFR conditions will continue through 03Z, with MVFR
ceilings moving in from the northwest to move over MBG/ABR/PIR by
04-06Z and remain through the TAF period. There is a 60% chance of
light snow this evening, lingering into the early overnight hours
at ATY. This light snow may temporarily bring visibility and
ceilings down into the IFR category at MBG/ABR/ATY.


&&

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

$$

UPDATE...TMT
DISCUSSION...07
AVIATION...06