A surge of arctic air has begun to make its’ way into the Northern Plains today and will continue to push southeast through the weekend. Temperatures could run as much as 30 degrees below normal in parts of the Central Plains. The cold airmass will first move quickly through the High Plains just East of the Rockies. From there, it will slowly progress east and south through the Midwest, Great Lakes, and Mid-Atlantic regions and modify (or warm) as it goes.
Snow will also accompany this cold blast in the northern states. Winter Weather Advisories are currently in effect for parts of Montana, Wyoming, and South Dakota where as much as 6 inches could accumulated over the next 24 hours. North Dakota, Nebraska, and Minnesota could also see snowfall as low pressure slides eastward over the next few days.
By the end of the week, high temperatures will struggle to reach the mid-50s across the Great Lakes and Northeast. As next week begins, temperatures could top out in the upper-40s in these areas and struggle to reach 60 in places like Philadelphia, Baltimore, and Washington, DC. I imagine many of these locations will see their first frost (if they haven’t already).