On the heels of the snowstorm that impacted portions of the Midwest region on Tuesday, another winter storm will move through Thursday into Friday as a new wave of energy associated with an active northern jet stream arrives.
The impacts will begin Thursday morning where we look towards the Northwest and Northern Plains. From Montana into western portions of the Dakotas, a light to moderate snow is expected as it overspreads into these areas. It’s not until the latter half of the day when the storm will become more organized resulting in heavier snowfall rates. During the afternoon and evening on Thursday, snow is forecast to fall from northern Montana and portions of the Dakotas through southern Minnesota, northern Iowa, and into the Chicago area, including southern Wisconsin and northern Illinois. Chicago and areas to the west will be in the sweet spot with this storm. The reason is that’s where the heaviest snow will set up. Between six and eight inches of snow is forecast to fall in that region, but some areas will likely receive as much as ten inches because of this effective snow-producing storm.
Throughout the night on Thursday, snow will gradually clear out of Montana and the Dakotas with snowfall intensities dwindling while a line of snow moves into northern Nebraska. To the east, the snow will persist across the similar areas of the Upper Midwest that dealt with it Thursday afternoon and evening in addition to the rest of Iowa and into more of the Great Lakes region. That includes extreme-northern Indiana and Ohio as well as most of Lower Michigan and as far east as western Pennsylvania and New York. We also want to note that a light freezing rain cannot be ruled out on the southern extent of this moisture, especially in southern Iowa.
During the day Friday, a band of heavy snow will likely set up from eastern Nebraska through central Iowa and into the Chicago area. Snowfall rates with this band will likely reach between one to two inches per hour, at times. Meanwhile in the Great Lakes region, the snow will continue to fall throughout the day across similar areas. Several hours of light snow is possible, however, even in much of New York, Pennsylvania, and New England. This is where the forecast becomes uncertain because it’s unclear how far south and east the moisture associated with this disturbance extends. Therefore, only a brief light snow shower is currently forecast for the New York City and Boston areas, however, stay tuned for any changes to this forecast. Either way, there is a very very low chance of significant snowfall occurring.
Friday night the snow will pull out of the Upper Midwest while it continues across the Great Lakes region through New England. The snow will clear out from west to east, so the snow will also come to an end in the Great Lakes by early-Saturday morning while continuing from Upstate New York through northern New England through about sunrise on Saturday. Once the snow comes to an end with this storm system, a new one will develop in the South, leading to another round of snow from the Ohio Valley through the interior Northeast. We’ll have the details on that storm later this week.
That leads us to our snowfall forecast for this end of week storm. There will be two different pockets of heavier snow: in Montana and from east-central Iowa through southern Lower Michigan, including Chicago and Detroit. With these two pockets, over half a foot of snow is expected. In Chicago, this storm will very likely be the biggest 2-day snowstorm this winter season. Their biggest of the 2017-18 winter is currently only 3.3 inches from February 4-5, 2018, which is the most recent snow event. Notice the very sharp snowfall gradient along the southern extent of where the snow is forecast to fall? If the track of this disturbance shifts by just a few miles, then some areas near the gradient may end up getting snow instead of receiving none.