Good afternoon everyone! Snow showers continue to be ongoing across the central portions of SD as of 4:15pm CST, though at a much weaker state when compared to this morning. This corridor of snow showers will continue to slowly lift northeast through the evening hours and bring better snow chances to the western portions of ND into tonight. However, additional accumulations with this weakening wave should generally remain under 1″.
Here’s a look at the current weather bulletins that are in effect across the Northern Plains: Our attention will turn towards a more substantial snowmaker for the southern and western parts of the region, which have allowed the National Weather Service to issue watches and advisories out ahead of the system. Winter Storm Watches have been issued for southwestern ND into northwestern and central SD while Winter Weather Advisories have been hoisted north of the Blackhills, southeastern SD and far southwestern MN. Expect the heaviest snows to come Saturday night into the day Sunday.
Simulation of temperatures through Sunday night: Expect another cold one out there tonight into Saturday morning as negatives for lows will be common in the eastern Dakotas into MN. The wind won’t be that much of a concern during this time, but watch for some areas, mainly in northern ND to have wind chills fall into the -20s. Through the duration of the weekend, most areas will hover in the single digits for highs, allowing for a powdery, high-ratio snow. Again, wind won’t be too terribly strong and may gust at times to 25mph, allowing for potentially low visibilities and patchy blowing snow.
There is the threat for freezing fog in northern MN and northeastern ND that could lead to some slick spots on the roadways late tonight through Saturday morning, gradually eroding as the day progresses.
As discussed in previous updates, out ahead of our next system will come enhanced upper-level divergence (shown below) which will aid in precipitation breaking out across the southwestern and eventually southern portions of the region. When winds diverge away from each other in the upper-levels, this supports convergence in the low-levels and subsequently lifting motion in the atmosphere to replace lost mass from the upper-levels. In short, snows are anticipated to break out again as Saturday progresses, adding to the snow cover in the area.
This next system will follow on the heels of the currently fading wave. As discussed, this wave has more upper-level support from the Jet Stream and favorable forcing for upward motion which will allow for this second wave to be more robust than today’s. Shown below is the simulated radar through 6am CST Sunday: There continues to be some discrepancies in the data even as of this evening with the European (shown below) being located slightly further south with the snows than the NAMs and the HRRR. This is huge for areas such as southwestern ND as some guidance is very aggressive while the European continues to be less. Regardless, expect scattered snows to break out within close proximity to the low pressure system across western SD by 6am CST Saturday and spread outward/gain coverage from there into the remainder of SD and southwestern ND through the remainder of the daytime hours. Snows will lift northward into southern MN from the Central Plains by midnight Saturday night. Heavier bands of snow will be common through the night across southwestern ND into much of SD and far southern MN.
The biggest risk to the forecast come Sunday will be as the snow works further north across the southern tier of MN. Dry air will be pushing downward from the north so we continue to remain on the lower side regarding snowfall totals for the Minneapolis area and points south. This area has low confidence given the dry air to the north which could cut down totals, but if any shifts north in track occur, could result in higher totals. Shown below is a look at low-level relative humidity with the yellow-dashed line representing the gradient.
Simulated radar from 6am CST Sunday through 6am CST Monday: The axis of snow stretching from western SD (potentially southwestern ND as well) through the remainder of SD into southern MN will slowly wane in coverage and intensity as Sunday progresses. By 6pm CST Sunday, lighter snows will remain in SD and far southern MN before coming to an end by Monday morning. However, residual weak energy aloft will keep light flurry chances alive Monday, especially in the Dakotas.
Northern Plains Snowfall Outlook Saturday through Sunday night: Snow will be more consistent and heaviest in far southwestern ND and northwestern ND where some low-level frontogenesis will aid in a likely band of 10-15″ of snow. There still remains some low confidence in the placement of this band as the NAMs and the HRRR are further north into more of southwestern ND while the European Model is more in line with what’s shown below. Definitely note that higher amounts are possible than what’s shown below in southwestern ND. Otherwise, a band of 6-10″ extends through central and southeastern SD while 3-6″ is likely just south of Bismarck and near Rochester. Amounts do steadily drop off the further north and east you head. Subtle differences in track and intensity are possible through this period so further adjustments may be needed over the coming day.
If you have any questions do not hesitate to reach out! Have a great evening!