634
FXUS63 KABR 110748
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
248 AM CDT Wed Mar 11 2026

.KEY MESSAGES...

- A few snow showers will pass from west to east this afternoon
  across the northern tier of the state. Limited accumulations
  expected.

- A clipper system brings strong winds in for Thursday afternoon
  and evening, although confidence is low in regards to peak
  strength/timing of the winds. Winds potentially could gusts up
  over 60 mph in central/north central SD and above 50 mph for the
  Sisseton hills region. High Wind Watch has been expanded into
  the James valley.

- Mild temperatures and dry conditions will raise fire weather
  concerns for Thursday afternoon as well. Fire Weather Watch is
  in effect. Very little overall precipitation with this system.

- Another area of low pressure will bring a 50 to 70% chance for
  snow or a mix this weekend. High and low temperatures Sunday
  into Monday will be about 15 to 20 degrees below normal.

&&

.DISCUSSION...
Issued at 216 AM CDT Wed Mar 11 2026

Snow continues to move east and out of the CWA. Focus for today is
the instability created by cool mid level temperatures, about a
standard deviation below climo at 700mb with an upper trough
directly overhead. NAM BUFKIT profiles indicate steep low level
lapse rates, and a decent convective layer from 5 to 15kft, deep
enough to generate snowfall, with a freezing level of 1 to 2kft.
CAMS also picking up on the convective nature of the environment.
Snow Squall parameter in the NAM highlights the northeast this
evening, however CAMS don`t look quite so organized in their
depictions. Given the nature of convection, NBM smooths it out so
have input a blend of CAMS to better detail the nature of
precipitation for the afternoon.

Ahead of the Thursday system, NAM BUFKIT profiles indicate a brief
period of favorable downslope conditions for the lee of the Sisseton
hills, with 50kts in the critical layer. Flow is mostly westerly and
the inversion weak so probably not going to exceed 60 mph at
Peever, however the HRRR and ECAM both top out in the low 40kt
range so up around 50 is definitely possible.

With the Thursday clipper, there is better consistency in model
placement and timing of the low track/intensity, though the use of
the adjective `better` here is me being passive aggressive. The GFS
still has the most consistency with a low moving through the far
northeast of Montana/northwest North Dakota straight through to
Fargo/Grand Forks and then making a short loop into the Western
Lakes region. The Canadian takes a flatter trajectory along the
ND/SD state line into the Western Lakes region. The EC is now in
line with the GFS, whereas yesterday it was quite a bit weaker
until the system rapidly deepens as it approached the Western
Lakes region. And the NAM is the largest outlier with the low
tracking along the International Border into northern Minnesota.
And there is still about a 10mb difference in the central
pressure of the low between models. Ergo the really really low
confidence in regards to wind speed intensity/timing and
precipitation. The GFS is probably the higher end in regards to
pressure rises on the backside of the system at 12 to 17mb per 6
hours. There is also a duel nature to the cold advection with two
surges showing up in the 850mb analysis between the main
deterministic models. The initial surge of modified Pacific air
goes across the area Thursday in the warm sector, followed by the
Arctic front Thursday evening. These being well separated in time
in the GFS/NAM with the EC on the opposite spectrum with just a
broad cold advection regime. This will influence when we go from a
warm to weakly cold advection regime followed by the stronger
cold advection. Unfortunately there is a lot of wind potential if
we can efficiently mix with 60-100ks of unidirectional flow in the
mid levels, so the ceiling on strong winds is pretty high, but
the confidence on achieving such strong winds is low. Previous
forecast input a blend of higher winds to account for the strong
cold advection and pressure rises associated with the system.

A last minute add on looking over the CAMS wind output lends a
little more confidence on expanding headlines for high winds as well
as the fire danger/red flag potential thanks to a wind shift in
conjunction with the winds ramping up to near warning levels.

As for precipitation, well this is a clipper with a low track to
the north. Warm advection wing will be short lived as it spends
time saturating down into a warmer, drier near surface layer. On
the backside, it will be weakly convectively unstable with wrap
around showers. NBM depiction of a few hundreds is perfectly
acceptable given the current uncertainties and overall nature of
regimes precipitation potential.

Will continue to stick with the NBM in regards to the shallow
amplitude track of this Colorado`esque type low Saturday. Still
some wiggle room between deterministic guidance which is trending
towards a north northwest to south southeast oriented deformation
band of precipitation somewhere across the region. NBM is mainly
presenting with snow initially Saturday morning with a transition
associated with both a diurnal and advection trend of warm air to
transition to rain for parts of the CWA before transitioning back
to snow. Too far out to tell how far north this rain/snow line
will wobble across the area.

The end of the weekend and start of next week continues to be very
cold, with 850mb temperatures a standard deviation below climo, with
the deterministic GFS more in line with GEFS values and the EC still
down to 20 below at 850mb. NBM has trended warmer, through the 25th
75th percentiles range is still about 10 degrees and we can see the
deterministic NBM currently falls closer to that 75th (warmer)
range.



&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1221 AM CDT Wed Mar 11 2026

Terminals KABR,KATY,KPIR,KMBG

VFR conditions behind a system this morning, with possibly some
fog once the high clouds clear out. Later today, for a few hours
there is a low probability of snow showers.


&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Fire Weather Watch from Thursday afternoon through Thursday
     evening for SDZ003>005-009-010-015>017-033>037-045-048-051.

     High Wind Watch from Thursday afternoon through late Thursday
     night for SDZ003>005-009-010-015>017-033>037-045-048-051.

     High Wind Watch from Thursday evening through late Thursday
     night for SDZ006-018.

MN...None.
&&

$$

DISCUSSION...07
AVIATION...07