Good afternoon everyone! There is an arctic front marching eastward across the region as of 4:15pm CST that is leading to a pulse of quick-hitting snow impacting eastern MN that will continue to drop light snow accumulations of generally less than 1″ before pushing out of the whole state by 8pm CST this evening. Watch for lower visibilities and areas of blowing snow given stronger wind gusts as this front pushes through.
Here’s a look at the current weather bulletins that are in effect across the Northern Plains. The National Weather Service has issued Winter Weather Advisories for portions of the eastern Dakotas and western MN due to blowing snow as the arctic front passes. Wind gusts upwards of 35mph at times will lead to reduced visibilities and help pick up snow and blow it around. However, this threat will slowly wind down tonight with the bulk of these advisories only running through the next few hours. Otherwise, Wind Chill Advisories are also in effect for ND, northeastern SD and western MN due to the bitterly cold temperatures and wind chills expected tonight into Friday morning.
Simulation of temperatures through Sunday: Temperatures will fall behind the arctic front that is swinging through the region, plummeting temperatures into the -10s in ND, northern SD and potentially far western MN by Friday morning. Look for wind chills in these areas to range between -20ºF and -35ºF. Daytime recovery will be minimal as temperatures fail to warm above 0ºF for most in ND, northeastern SD and far western MN. Bitterly cold temperatures in the negatives remain likely in the eastern two-thirds of the region into Saturday morning.
Our next system to track will mainly impact the western portions of SD, at least late tonight into Friday morning before slowly meandering northeastward and weakening across western ND and central SD into the afternoon hours. As shown below, the greatest threat for snow (on the order of several accumulating inches) will reside within the circled region of western SD due to enhanced warm air advection and frontogenesis. As talked about in previous updates through the winter, this aids in lift and the development of snow.
Simulated radar through 12am CST Friday night: The thin stripe of snows impacting eastern MN will quickly work out of the state by 8pm CST this evening. Winds will remain gusty this evening (shown in the second image) into tonight, helping to blow and drift snow. As we work into the overnight hours tonight we will build in snow coverage across southwestern SD starting generally after 12am CST that works into the remainder of western SD through the overnight into Friday morning. This band of snow will move slowly northeastward through this time into southwestern ND and eventually central SD by the afternoon. However, the frontogenesis aiding in keeping the band around will diminish and so will the snow as afternoon progresses into evening and early overnight. A thin band of light snow may remain in western ND by the end of this loop.
Snowfall through Saturday morning: No changes were made to the snowfall graphic from this morning as our forecast remains on target per the latest guidance. Aided by some weak frontogenesis, a band of 4-6″, isolated 7″ is likely by Saturday morning for portions of western SD, including the Rapid City area. While no Winter Weather Advisories have been issued in these areas, we would not be surprised if some were given the snow that is expected. As you head north and east, snow amounts will drop off as forcing becomes less favorable.
As discussed in this morning’s update, out ahead of our next system will come some enhanced upper-level divergence (shown below) which will aid in precipitation breaking out across the 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 the lost mass from the upper-levels. In short, snows are anticipated to break out again through the day Saturday, adding to the snow cover in the area.
This next storm system Saturday will follow on the heels of the incoming wave tonight into Friday. As discussed, this wave has more upper-level support from the Jet Stream and favorable forcing for upward motion which could allow for this second wave to be more robust and widespread than the first. Shown below is the simulated radar from 12am CST Saturday through 12am CST Monday: Since this morning’s update, the European Model has shifted further south some in more compliance with the GFS models, but confidence does still remain low with this system’s evolution and snowfall totals (more on totals later). Regardless, expect snows to break back out within close proximity to the low pressure system across western SD Saturday morning and spread outward from there into the remainder of SD, southern ND in the afternoon and evening then eventually southern MN Saturday night. Heavier bands of snow will be common before another weakening trend occurs through the day Sunday, but continues to keep at least widespread light snows in similar areas even into Sunday night.
Total snowfall through Sunday: Please note that the graphic below takes into account snows from both systems through the weekend, even the event tonight through Friday. Between the two storm systems, a general 6-10″ of snow is expected to fall in far southwestern ND into much of SD while a swath of 3-6″ will extend eastward into the southern portions of MN. MN will largely miss out on the first event, so most of what’s shown below comes Saturday night into Sunday. Amounts do steadily fall off the further north you head as these will be more southern events. We also wanted to mention that the totals depicted in western SD are quite conservative and many areas will easily overachieve. However, the exact placement of these higher totals cannot be nailed down at this time, hence the locally higher depicted below. Subtle differences in track and intensity through this period are likely and adjustments will be needed over the coming couple of days.
If you have any questions do not hesitate to reach out! Have a great evening!