Atmospheric River to Hit Pac Northwest and California; Snow Could Impact Parts of Northeast And Great Lakes

Meteorologists are forecasting a stormy pattern that could impact millions of people across U.S. this week with the threat of flooding, travel disruptions and the potential for the first accumulating snowfall of the season in some places.

Flooding rainfall and mountain snow are expected along parts of the West coast this week, with the worst of the impacts expected to occur across Northern California, according to an AccuWeather forecast released on Monday.

Between Tuesday afternoon and Friday, the potential exists for 8 inches to 12 inches of rainfall in Northern California with a maximum of 20 inches of rain possible, according to AccuWeather.

Conditions are expected to deteriorate along the Interstate 5 corridor from Northern California into western Oregon and Washington on Tuesday before a plume of moisture is expected to focus the risk for major flooding across Northern California on Wednesday, which can then continue to rain over the same areas repeatedly through Friday.

The plume of heavy rain is expected to heighten the risk for mudslides, debris flows and road closures in many burn scar areas across the region later this week. Meteorologists say there is an elevated risk of life-threatening impacts in the Park Fire burn scar area.

Heavy snow is expected to span across the Cascades, northern Rockies and northern Sierra Nevada Range, posing a risk to travelers on mountain pass roads. Road closures are possible as a result of this storm, according to AccuWeather.

AccuWeather meteorologists say wind gusts of 50 to 60 miles per hour are possible in the mountains and gusts of 60 to 70 mph are possible along the Pacific Coast Tuesday with a maximum of 90 mph.

In the Midwest, some areas may get the first accumulating snowfall of the season from a major storm brewing expected over the Great Lakes this week.

The storm could also produce gusty winds and rain in some areas that are dealing with fires or drought.

The winds will ramp up on Wednesday and peak during Thursday and Friday but may persist in some areas through the weekend, according to AccuWeather.

Snow will fall along with the cold air, and as the cold air passes over the warm waters of the Great Lakes, lake-effect snow will develop and can become locally heavy. Snow is also likely to develop farther south with the colder air over parts of the Ohio Valley and the central and southern Appalachians beginning Wednesday night and lasting in some areas into the weekend, according to AccuWeather.

Meteorologists are forecasting a zone of 3 inches to 6 inches of snow in the higher elevations of southwestern Pennsylvania and parts of Maryland and West Virginia, with a maximum of 24 inches.