196
FXUS63 KABR 051129
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
529 AM CST Fri Dec 5 2025

.KEY MESSAGES...

- Precipitation lingers this morning, with a wintry mix of snow,
rain, and freezing rain possible. Precipitation rates will be light,
and less than half an inch of additional snowfall accumulation is
expected.

- Snow returns Saturday as a clipper system moves through. 1"-3" of
accumulation will be possible east of the Missouri River through
Saturday evening, with up to 2" possible along and west of the
Missouri River.

- There will be periodic lower chances for precipitation (20-40%)
through early next week, as more weak weather systems have the
potential to move through the region.

- Strong northwest winds of 20 to 35 mph with gusts in excess of 45
mph are a concern from late Tuesday afternoon through Wednesday
morning.

&&

.UPDATE...
Issued at 528 AM CST Fri Dec 5 2025

The aviation discussion below has been updated in accordance with
the 12Z TAF issuance.

&&

.SHORT TERM /TODAY THROUGH SATURDAY AFTERNOON/...
Issued at 242 AM CST Fri Dec 5 2025

Currently (~08Z) watching light precipitation traverse across the
Aberdeen forecast area. Surface observations of both snow and rain
have been reported this evening, with the rain mainly due to some
areas staying above freezing to this point. Overnight lows across
the area are expected to be near to just below freezing, so it is
possible that if temperatures overachieve this morning some areas
could see light rain over light snow through the night. Ice
production is generally expected aloft, which is supported by radar
observations showing no signs of a melting layer present. With
surface temperatures dropping near freezing. it will also be
possible to see pockets of freezing rain this morning. Regardless of
what precip type is falling, rates will continue to be light and
accumulation of a few hundredths of liquid equivalent (less than
half an inch of snow) is expected. Precipitation will linger through
late morning into the early afternoon at the latest, giving way to
dry conditions and weakening winds overnight tonight.

The next clipper system moves through on Saturday, supporting snow
across the forecast area. The low pressure center is expected to
track over the WY/SD/NE state borders Saturday morning continuing
southeasterly through the afternoon, putting the Aberdeen CWA on the
northeastern side of the low. There is some slight disagreement in
model soundings when looking at where the lift will be in relation
to the DGZ. The current expectation is for SLRs to sit somewhere
within the 10-15:1 range, although parts of central South Dakota
could fall lower depending on the exact track of the low and how far
north warmer air is able to penetrate (which would remove some of
the snow growth out of the DGZ the more warm air pushes north).
Ultimately regardless of snow ratio, ensemble mean QPF through
Saturday evening is around 0.05"-0.10" over central and north
central South Dakota, increasing to around 0.10"-0.20" moving into
eastern South Dakota. This translates to an expectation of around 1"-
2" across most of the CWA, with some higher totals over the east. It
is worth noting that this is a slight increase from the past
forecast cycle, particularly over eastern South Dakota. Looking at
90th percentile values in the NBM as a proxy for a reasonable "worst-
case scenario", snowfall values in the east remain at 4" or below
for the duration of the event. With all that in mind, there are no
plans to issue any headlines for this event at this time.

Wind may also cause some minor issues with this snowfall in the form
of drifting snow. As snow is falling over central South Dakota,
northeasterly winds around 15-20 miles per hour will be present,
with gusts up to 25-30 miles per hour. With snowfall rates expected
to be fairly low and wind speeds falling somewhat short of a typical
Blowing Snow event, widespread impacts are not anticipated. However
the wind and fresh snowpack will likely be enough to cause some
isolated drifting snow. While not high-impact, drifting snow may
make driving a bit more dangerous at times.

&&

.LONG TERM /SATURDAY EVENING THROUGH THURSDAY/...
Issued at 242 AM CST Fri Dec 5 2025

From Saturday evening through the end of the period, the over-
arching flow pattern theme remains "positive PNA". Northwest flow is
still lining up transient clipper-like shortwaves over the region,
each one separated from the next by roughly 24 hours.

With the active pattern of low pressure systems working through, the
low level thermal advection pattern will be pretty busy. Weak low
level CAA is happening Saturday night into Sunday morning, but low
level WAA is expected to kick in by late in the day Sunday and
persist into Monday. Warm air is forecast to stick around Monday
night into Tuesday before the next system`s strong cold frontal
passage knocks temperatures back down to near to below normal for
the middle of next week.

The probabilities of seeing a 0.10in or more of water equivalent in
any given 24 hour period in the out periods is low (less than 10
percent). Likewise, the chances of seeing 0.01in or more of freezing
rain/ice accumulation or 3 inches or more of snow are low. That
being said, the clipper system moving through North Dakota into
Minnesota Tuesday/Wednesday will need to be watched closely for any
shifts further south in track/placement, as this system holds the
chance of producing headline-able conditions. But for now, model
output/ensembles are still maintaining that the bulk of this system
will track through the region north of this CWA.

Looking a little bit more closely at the wind potential
Tuesday/Wednesday, it appears that a corridor of fairly strong winds
(off the surface) will be overspreading the CWA while it`s within
the warm sector of the clipper system. Current model progs suggest
that it`s not until at or after 21Z Tuesday that strong winds aloft
will be able to be mixed down to the ground, as that is roughly what
time the system`s cold frontal passage is slated to begin sweeping
through the CWA, first across north central South Dakota, but then
quickly following through central and northeast South Dakota and
west central Minnesota, especially at or after 00Z Wednesday when
strong low level CAA, pressure rises and winds just a half kilometer
off the ground will be working in tandem to present a strong wind
concern. Not too confident about a blowing snow concern, though, if
the CWA has been at or above the freezing mark for nearly 48 hours.
Thinking there may not be much blowable snow left after warm
boundary layer conditions like that.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 528 AM CST Fri Dec 5 2025

Terminals KABR,KATY,KPIR,KMBG

The main aviation impact this morning is the lingering precipitation
over the forecast area this morning. With temperatures hovering near
freezing, a mix of snow and rain is falling early this morning, with
some chances for some freezing rain as well. Precipitation rates are
expected to be fairly light, but the heaviest precip may reduce
visibility to MVFR status. However, flight category will be dictated
more by the ceilings this morning, and varying VFR, MVFR, and even
IFR ceilings are present (the latter of which is associated with the
heaviest precipitation). The expectation moving forward is for an
MVFR cloud deck to persist through the rest of the morning,
occasionally dipping down to IFR where the heaviest precipitation
is. Once precipitation clears up around 18Z, the rest of the TAF
period is expected to be dry, but MVFR ceilings will persist.

The only other aviation concern of note is wind gusts this
afternoon. Winds will come out of the north, reaching 20 to 25 knots
at their peak. Winds are expected to die down overnight tonight and
turn southeasterly ahead of the incoming low pressure center that
will bring the next round of snow on Saturday.

&&

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

$$

UPDATE...BC
SHORT TERM...BC
LONG TERM...10
AVIATION...BC