Sisseton, South Dakota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

832
FXUS63 KABR 131800 AAC
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1200 PM CST Tue Jan 13 2026

.KEY MESSAGES...

- Mild temperatures around 20 degrees above normal are expected
  today with highs generally in the 40s to around 50 degrees and
  overnight lows in the 30s. Much colder conditions, even colder
  than normal for mid January, return late in the week.

- A 30-60 percent chance for light rain today across central South
  Dakota before an increased chance of 45-75 percent of snow
  possible Thursday and Friday. Accumulations look minimal, but
  there could be up to an inch (60-80 percent chance) of snow
  accumulating up on the Prairie Coteau late Thursday into Friday.


- Strong northwest wind gusts of 35 to 45 mph are forecast today,
  but may be easier to come by later tonight. Even stronger winds
  may be possible late Thursday through Friday where peak wind
  gusts may range between 40-55 mph. This combined with any
  snowfall could lead to reduced visibility and hazardous weather
  conditions.

&&

.UPDATE...
Issued at 1138 AM CST Tue Jan 13 2026

The aviation discussion has been updated for the 18Z TAFS.

UPDATE Issued at 1014 AM CST Tue Jan 13 2026

Made some minor adjustments to winds, sky condition and PoPs to
bring them in line with sfc, satl and radar observations this
morning. The majority of the showers have stayed west of the
Missouri River so far this morning. Looks like that`s primarily
where they will remain into this afternoon with a few occasional
lighter showers on the eastern side of the Missouri Valley.
Overcast skies across central SD all day will be contrasted with
sunshine through the midday hours across northeast SD and west
central MN. Increasing clouds will eventually move into those
zones this afternoon as a cooler air mass begins to work south
into that area.

&&

.SHORT TERM /TODAY THROUGH WEDNESDAY AFTERNOON/...
Issued at 329 AM CST Tue Jan 13 2026

At 3 AM CST, under a partly cloudy sky, unseasonably warm
temperatures are running in the 30s and 40s. Winds at the surface
are west-northwest 10 to 20 mph with gusts to 30 mph or higher. Off
the surface, in and above the low level thermal inversion in place,
winds are northwest at 30 to 40 knots. It`s also tough to ignore the
150+knot upper level jet streak sweeping down across the region on
the back of the west coast upper level ridge.

Models/guidance have really backed off on the amount of inversion
erosion there could be in this "warm sector" environment over the
CWA today during daytime heating/mixing. It does not look all that
promising. But, if some of the ridge-tops in the CWA do manage to
accomplish enough mixing to tap into these winds off the surface,
gusts to 45 mph (the bottom of wind advisory gust criteria) would be
a thing. Despite the high-end relative humidity around today, and
the potential for measurable rain across central South Dakota, the
expected west-northwest winds of 15 to 30 mph with higher gusts will
hold the Grassland Fire Danger index in the high to very high
category over, at least, the western two-thirds of the CWA today.

Tonight`s wind forecast will prove the most challenging, as an
arctic cold front attached to a surface low (currently analyzed more
than halfway through Manitoba and Ontario) will push south/southwest
through the CWA. Strong low level CAA in its wake, along with low to
moderate pressure rises (6 to 12 hpa in 6 hours), could make the
case for a 3 or 4 hour window of advisory criteria north winds over
the CWA later tonight, generally along and east of a line from Leola
to Clark. Also, all along and behind this fropa, there could be
light rain/snow showers or sprinkles/flurries.

Guidance shows this boundary pretty much stalling out in a north-
south orientation over the Missouri River valley late tonight/early
Wednesday morning. The combination of low level forcing from the
stalled/stationary front and any available mid/upper level lift
support could mean additional very light precipitation potential
(flurries) extending into Wednesday. High temperatures on Wednesday
will also prove challenging as conditions west of this stalled
boundary will continue to be mild, like the past couple of days, so
highs nosing up into the 40s, especially west river, are certainly
possible, while the arctic cold air settling over the eastern CWA on
the cold air side of the boundary will likely not get out of the
teens to low 20s. Surface high pressure will move through the CWA on
Wednesday, which should mean a break in the strong winds.

&&

.LONG TERM /WEDNESDAY EVENING THROUGH MONDAY/...
Issued at 329 AM CST Tue Jan 13 2026

The main focus in the extended period is the snow and wind
combination that is expected late this week. The driver of this
system will be a low pressure center supported by an embedded wave
riding down the transition area between and upper-legvel ridge to
the west and a trough to the east. The low is expected to bring
multiple fronts across the forecast area Thursday and Friday,
providing lift for precipitation development. Overall liquid
equivalent amounts are expected to be fairly minimal, and ensemble
50th percentile values show just upwards of a tenth of an inch
possible for the 48 hour period ending at 12Z on Saturday. SLRs will
increase through the event, making it a little difficult to make a
direct conversion from liquid to snowfall totals, but median values
for the same time period show around an inch of snow with some
localized areas of 2 inches possible over the Prairie Coteau.

Winds are expected to increase Thursday and Friday as well, thanks
to the pressure gradient tightening with the incoming low. At this
point, the NBM is fairly confident in Advisory level criteria over
most of the forecast area (50-80% for 45 miles per hour) Thursday
and Friday, with some slightly broader coverage on Friday. High wind
warning criteria being reached is still a bit borderline (pockets of
10-30% chances for 58 miles per hour, mainly located over central
and north central South Dakota). However, with the NBM`s tendency to
under-perform on winds under northwesterly flow regimes, it`s hard
to rule out consideration of a High Wind Warning at this time.

With both the snow and wind in mind, it becomes fairly clear that
anywhere snow is falling will see drastic reductions in visibility
Thursday and Friday. A Blizzard Warning is undoubtedly on the table
for this event still, but a closer look reveals that the setup
actually appears quite favorable for a Snow Squall event. Running
through a quick checklist, models indicate that out ahead of the
front, there will be strong upward vertical motion in the lowest
levels and continuing up through the DGZ as well as bands of strong
low-level frontogenesis. These factors are corroborated with 0-3km
lapse rates between 5-7 C/km. Strong pressure rises behind the cold
front are expected, and negative values of Equivalent Potential
Vorticity will be present as well. Perhaps the one drawback is
SBCAPE values a bit lower than optimal (only around 30-50 J/kg where
optimal environments would prefer upwards of 50 J/kg). However with
all of the other stability parameters looking favorable, as long as
some SBCAPE is present it will likely be enough to get some
convection going. All of this is reflected in the Snow Squall
Parameter, reaching values of up to 6, the highest values showing
overnight Thursday into Friday. Therefore confidence at this time is
decently high in some sort of snow squall event occurring. The main
consideration moving forward will then become how widespread falling
snow will be. Broader coverage will likely push towards a Blizzard
Warning, while a more localized look to the models (not unlike what
the NBM is already displaying) will push more towards individual
snow squall warnings. The situation will continue to be monitored
over the next day or two to attempt to reconcile the best course of
action for this event.

The broader pattern of an upper-level ridge over the western CONUS
exerting influence is expected to persist through this weekend and
into the start of next week. Even so, high temperatures will return
to normal to just above normal for mid-January. No further
precipitation is anticipated for the remainder of the forecast
period.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1138 AM CST Tue Jan 13 2026

Terminals KABR,KATY,KPIR,KMBG

VFR conditions and gusty northwest winds will prevail through this
afternoon at all terminals. This, despite overcast skies and rain
showers moving through parts of central SD. KPIR will see the
majority of this with light rain chances continuing through the
first half of the afternoon. Sub-VFR cigs will gradually work
into northeast SD this afternoon with KABR/KATY going MVFR late
this afternoon and early evening. This stratus deck will continue
shifting west-southwest and eventually KPIR/KMBG will see MVFR
cigs by mid to late evening tonight. There will be some pockets of
sprinkles/flurries or a brief light rain/snow shower overnight as
a cold front pushes south-southwest through the area. However,
chances are too slim with limited coverage expected to include
mention of it in the TAFS. KABR/KATY will return to VFR
conditions by daybreak Wednesday while KPIR/KMBG remain MVFR
through the end of this TAF cycle. Gusty northwest winds between
25 to 35 knots will persist today and tonight before eventually
diminishing through the morning hours on Wednesday.

&&

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

$$

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