textproduct: Aberdeen

KEY MESSAGES

- Sisseton hills downslope winds expected later this afternoon through the evening. Winds to peak in excess of 50 mph. Snow moving in during the evening could result in intermittent and significant reductions in visibility.

- Snow moving across the state today to accumulate around an inch or two. As the system moves east, west river through the Missouri valley may get a light glaze of ice.

- Near to above normal temperatures are forecast for much of the 7-day forecast.

SHORT TERM /TODAY THROUGH SATURDAY/

Issued at 156 AM CST Sat Jan 31 2026

Overall not much change in the assessment of the trough moving through with some light snow followed by a transition to a mix. Winds also stay about the same, with a stiff south breeze and Sisseton hills downslope winds.

With regards to the downslope timeframe/intensity, NAM BUFKIT profiles begin to indicate downslope begins around 18Z with a peak in the critical layer of 50kts around 00Z. That is about when snow sets in for the Sisseton point. So, thus there is a short window in which the downslope winds phase with snow around 00-03Z with the winds dropping thereafter. Thus not overly concerned for impacts as existing snow cover in the area has been shown to not really matter as we've had a previous downslope a week ago that registered a 67 mph gust and not really anything on the webcam.

Will leave the winter weather headlines in place for now as well, as there is probabilistic information to support a light glaze of ice. A deeper look into the BUFKIT profiles however suggest the evidence is less clear. As the bulk of the precipitation (snow) moves east, we are left with some residual moisture and ascent. In phase with the loss of ice and lift, we see just a sliver of the warmest portion of the inversion work its way above freezing. NAM BUFKIT profiles suggest a layer of approximately 500 feet. Below this is also a deep cold layer to the surface. The HRRR and RRFS also suggest more dry air working into the profile which would cut off precipitation entirely, and that is probably more appropriate as winds shift to southwest and then northwest.

So continuing the winter weather headlines, though with significant reservations such as: are we actually seeing precipitation as profiles warm? Is the layer thick enough for melting? Is the sub- freezing layer that follows thick enough for re-freeze. Is there too much dry air in the profile. The latest HREF is only generating about 0.01 to 0.02 inches of ice, and less than a 30-50% probability of exceeding that limited to Dewey/Jones/Stanley and points west. And the biggest question is, what impact will this even have if its falling on a 1/2" to 1" of fresh snow?

And as for snowfall, again not much change with just a slight re- arrangement of totals here and there. Overall HREF and NBM both point to about 1".

LONG TERM /SUNDAY THROUGH THURSDAY/

Issued at 156 AM CST Sat Jan 31 2026

At 00Z Monday the surface weather map will have high pressure over central Canada, with a ridge extending south across the eastern Dakotas, with the exiting low over Ontario with the cold front draped well to our south. The coldest air at 850mb will have already shifting to our east. Still, we'll remain under a pattern with the coldest air with 850mb temperatures of -5 to -9C remaining over northeastern SD and west central MN through Tuesday morning. This cooler airmass will move over the entire forecast area during the day Tuesday as the Canadian high moves over northeastern SD and MN.

The main 500mb trough moving through the northwesterly flow will be over MT early Monday morning, and continue across the Dakotas later Monday into early Tuesday, with additional weaker waves lingering over the area through Tuesday night. The result will be plenty of clouds, along with a 20-40% chance of light snow late Monday afternoon through Tuesday. Precipitation looks limited, but with snow to liquid ratios of 10-15:1, a quick dusting to around a half an inch of snow is not out of the question. The probability of 1" or more snow is 20% or less, maxing out over the James River Valley at this time.

The rest of the forecast period, through the start of next weekend, looks mainly dry. However, we will be watching the evolution of the surface low Thursday over south central SD that will push a warm front across the Dakotas and MN and bring the warmest air of the week with highs topping out in the upper 30s east of the James River to the 40s and even 50s elsewhere (highest over south central SD). Given the deviation from what has occurred temperature wise over the past few weeks, the temperature forecast for Friday and Saturday may end up being warmer (by around 5 degrees or so) than the current NBM forecast of 20s to low 40s. We'll continue to monitor the trends for the end of the week through early next week as a warmer pattern takes hold.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 522 AM CST Sat Jan 31 2026

Terminals KABR,KATY,KPIR,KMBG

VFR conditions with a trend towards MVFR and possibly IFR VISBY/CIGS as snow moves into each terminal. As the system departs, could be a brief period of mixed precipitation.

ABR WATCHES/WARNINGS/ADVISORIES

SD...Winter Weather Advisory until 5 PM CST /4 PM MST/ this afternoon for SDZ003-004-009-015-016.

Wind Advisory from 2 PM this afternoon to 9 PM CST this evening for SDZ007-008-021-023.

Winter Weather Advisory from 11 AM CST /10 AM MST/ this morning to 5 PM CST /4 PM MST/ this afternoon for SDZ033>035-045- 048.

MN...None.