Sisseton, South Dakota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

627
FXUS63 KABR 261139 AAA
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
639 AM CDT Thu Mar 26 2026

.KEY MESSAGES...

- There is 30-60% chance of light rain over northern SD early this
  morning, primarily north of US-12. Rainfall accumulations up to
  0.10" are expected, with locally higher amounts possible.

- As temperatures cool behind a passing cold front this morning,
  rain will mix with and then change to snow. At most, only a
  couple of tenths of an inch of snow on grassy surfaces is
  expected.

- Winds out of the north will gust 30 to 40 mph this morning
  behind the cold front, before slowly diminishing through the
  rest of the day. Another round of gusty winds may be possible
  Thursday night into Friday morning, with gusts of 20 to 25 miles
  per hour possible.

- Highs in the upper 30s to 40s will be roughly 5 degrees below
  normal Thursday and Friday. Above normal temperatures return for
  the weekend, with highs in the 60s and 70s.

&&

.UPDATE...
Issued at 629 AM CDT Thu Mar 26 2026

See below for an aviation forecast discussion for the 12Z TAFs.

&&

.DISCUSSION...
Issued at 131 AM CDT Thu Mar 26 2026

Currently (~06Z) monitoring a cold front dropping into the forecast
area, which will help facilitate precipitation development early
this morning. There is still quite a bit of uncertainty in where
exactly the band of precipitation will set up this morning. In
general, there seems to be a trend across model guidance to bring a
stripe of 0.10"+ further south and into northern South Dakota. With
such a narrow band being resolved, precipitation amounts may vary
significantly over a short location. To add to the complexity, there
is decent disagreement between the CAMs on the highest precipitation
amounts. There are a few models still putting out some more
aggressive totals (between a quarter of an inch and half an inch
through the event), but the latest runs seem to trend towards a
tenth to a quarter of an inch of liquid equivalent at the most.

Precipitation type adds yet another layer to tonight`s forecast.
With the passage of the cold front, the profile will cool down and
potentially facilitate a transition to snow this morning. Expecting
most of the precipitation to fall as rain, as temperatures won`t
reach below freezing at the surface until near sunrise this morning.
However still expecting that transition once both the upper-levels
cool and begin producing ice aloft as well as those surface
temperatures dropping below freezing. Can`t rule out freezing rain
either, although warm ground temperatures may limit potential for
any accumulation there. Overall only expecting a couple hundredths
of liquid equivalent to fall as winter precip, with fairly minimal
impacts overall.

Behind the front, winds turn northerly and increase, and are
expected to peak during the morning hours today. Expecting a shallow
mixing layer, which will limit the ability of the strongest winds
aloft to mix down. Low to mid-level winds are also expected to push
south through the day today, limiting the potential in the afternoon
as well. Still, gusts up to 30-40 miles per hour will be possible
this morning, diminishing slowly through the afternoon and evening
hours. The gusty winds lingering in the afternoon (25-30 miles per
hour) will create some elevated fire weather concerns over much of
the area, but minimum humidity upwards of 45 percent will keep
conditions from becoming critical.

850mb temperatures today drop behind the front, ranging from 0 to -5
Celsius, which is roughly the daily median to 25th percentile
respectively. As a result, expect slightly below normal temperatures
(highs in the upper 30s to 40s) today, including poor temperature
recovery this afternoon leading to a non-diurnal temperature trend.
A reinforcing shot of cold air advection comes early Friday morning
in the form of a brief period of strong low to mid-level winds (with
the jet aloft reaching upwards of 50 knots). However, not expecting
strong mixing to the surface overnight, so only forecasting a couple
hours of 20-25 mile per hour gusts overnight. Still, this cold air
advection continues the slightly below normal temperatures Friday,
keeping highs once again in the upper 30s to 40s.

Another longwave ridge is set to move over the western CONUS this
weekend, a familiar pattern that will allow for a warm airmass to
return to the Northern Plains. Expect temperatures above normal for
late March, with highs in the 60s and 70s through at least the
weekend. These warm temperatures (and associated humidity values)
may help create elevated fire weather concerns this weekend when
combined with winds. Unlike recent longwave setups over the past
month, ensemble cluster are supportive of the ridge continuing its
progression eastward, giving way to a longwave trough by the end of
the week. With the arrival of this trough will come the return of
precipitation chances. Uncertainty is still high so far out, so more
details on this system will come with later forecasts, should it
even materialize over the Aberdeen forecast area.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 629 AM CDT Thu Mar 26 2026

Terminals KABR,KATY,KPIR,KMBG

Satellite imagery and the latest guidance shows post-frontal
stratus developing/spreading south across the region. KMBG and
KABR are already MVFR/IFR, and KPIR/KATY are expected to get into
this stratus cloudiness within the next couple of hours. Expecting
this sub-VFR low cloudiness to persist for several hours today
before any improvement has a chance of happening. Currently, all
four terminals are in between areas of precipitation. Guidance
suggests that between now and 21Z, the terminals that stand the
best chance of experiencing light snow precipitation are
KMBG/KPIR as bands of precipitation lift out of the central and
northern high plains, spreading across the western Dakotas, before
running into increasingly dry low levels and dissipating. The
northerly winds gusting to 25 to 35 knots will gradually subside
late this afternoon through late this evening.

&&

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

$$

UPDATE...10
DISCUSSION...BC
AVIATION...10