At a Glance

A long-lasting snow event will continue this week from the Rockies into the northern Plains.This is due to a sharp plunge of the jet stream bringing cold air to those regions.The heaviest snowfall will be in higher elevations.

The first widespread snowfall of the season will continue to impact the Rockies and the northernPlains through the middle portion of the week ahead.

(MORE: )

Snow has already been falling in parts of the northern and western United States over the last few days.

Rapid City, South Dakota, saw its first flakes of the season Sunday night into Monday morning.

Accumulating snow spread as far south as Flagstaff, Arizona, early Sunday morning, with 0.7 inches reported atFlagstaff Pulliam Airport.Additionalsnow reports from the past several days can be found at the bottom of this article.

The National Weather Service has posted winter weather advisories for parts of Wyoming, southeastern Montana, western South Dakota and northwestern and north-central Nebraska.

Here's a look at the timing and locations where accumulating snow is expected in the week ahead.- Tuesday: Snow continues from the northern and central Rockies into the High Plains, including the western Dakotas and possibly western Nebraska. Tuesday night, colder air may change rain to snow in much of the Dakotas, northwestern Nebraska and northwestern Minnesota.- Wednesday:Snow (or rain mixed with snow) will continue from eastern North Dakota and northeastern South Dakota into northern Minnesota. Snow continues in the northern and central Rockies and possiblythe adjacent High Plains.- Thursday: Lingering snow(or rain mixed with snow)is possible in the Rockies and High Plains.

(MORE: )

Most areas in the northern Plains will see accumulations of less than 6 inches. The highest elevations of the northern and central Rockies will see a foot or more.

Those with travel plans in the Rockies and High Plains should check back with us at weather.com for the latest on this forecast.

Recap: Snowfall Reports So Far

Parts of northern Arizonapicked up accumulating snow Saturday into early Sunday. Up to 6 inches was reported at Arizona Snowbowl, with 0.7 inches measured in Flagstaff, according to the National Weather Service.

Denver picked up its first measurable snow of the season early Saturday, with a half-inch measured at the airport east of the city.

(MORE:)

The first accumulating snow of the season fell in parts of the Upper Peninsula of Michigan and early Friday. One inch of snow was measured at the National Weather Service office outside of Marquette, Michigan.

Thursday into Friday, the season's first snow also dusted parts of . More accumulating snow blanketed some not-yet-open ski resorts of Montana on Thursday as well.

Earlier last week, an estimated 18 inches of snow buried Glacier National Park, Montana. Several vehicles were stranded for a time at Many Glacier, according to the National Weather Service.