Snow forecasts and what to know as major winter storm crosses much of the US

A major winter storm forecast to produce heavy snow, significant ice and frigid temperatures was set to begin in the central U.S. on Saturday and move east over the next several days, according to the National Weather Service.

Here is what to know about the storm expected to affect millions in the eastern two-thirds of the country:

Major winter storm sets up

A large system made landfall along the West Coast on Friday afternoon, bringing rain to the Pacific Northwest with snow expected in the Cascade Mountains, according to meteorologists.

The system will be responsible for the development of a major winter storm from the Central Plains to the Mid-Atlantic this weekend into early next week.

Snow to fall throughout Central Plains and move east

By Saturday evening, widespread heavy snow is likely in areas between central Kansas and Indiana, especially along and north of Interstate 70, where there is a high chance of at least 8 inches (20.3 centimeters).

For places in the region that typically experience the highest snow totals, it may be the heaviest snowfall in at least a decade, meteorologists said.

The storm will then move into the Ohio Valley, where severe travel disruptions are expected. It will reach the Mid-Atlantic states on Sunday into Monday.

Blizzard conditions possible

Wind gusts higher than 35 mph (56 kph) and heavy rates of snowfall could lead to blizzard conditions, particularly in Kansas and nearby portions of the Central Plains by Sunday morning.

Whiteout conditions may make driving dangerous to impossible and heighten the risk of becoming stranded.

Freezing rain expected from eastern Kansas to the Ozarks

Dangerous sleet and freezing rain, particularly detrimental to power lines, also is anticipated to start Saturday from eastern Kansas to Missouri, Illinois, Indiana and much of Kentucky and West Virginia.

Treacherous travel conditions are expected with power outages likely in areas with more than a quarter-inch (a half centimeter) of ice accumulation.

“It’s going to be a mess, a potential disaster,” private meteorologist Ryan Maue said.

Frigid air from the Artic to blast areas as far south as Florida

Starting Monday, hundreds of millions of people in the eastern two-thirds of the country will experience dangerous, bone-chilling air and wind chills, forecasters said.

Temperatures could be 12 to 25 degrees Fahrenheit (7 to 14 degrees Celsius) colder than normal as the polar vortex stretches down from the high Arctic.

“This could lead to the coldest January for the U.S. since 2011,” AccuWeather Director of Forecast Operations Dan DePodwin said Friday, noting there could be up to a week or more of “temperatures that are well below historical average.”

The biggest drop below normal is likely to be centered over the Ohio Valley, but significant and unusual cold will extend south to the Gulf Coast, said Danny Barandiaran, a meteorologist at the National Weather Service’s Climate Prediction Center.

A hard freeze is even expected in Florida, he added.

“The wind chills are going to be brutal,” Woodwell Climate Research Institute climate scientist Jennifer Francis said. “Just because the globe is warming doesn’t mean these cold snaps are going away.”

Weather may be triggered by a fast-warming Arctic

The brutal weather may be triggered in part by a fast-warming Arctic, a reminder that climate change gooses weather extremes, said Judah Cohen, seasonal forecast director at the private firm Atmospheric and Environmental Research.

The polar vortex — ultra-cold air spinning like a top — usually stays above the North Pole, but sometimes stretches down to the U.S., Europe or Asia, causing intense doses of cold.

Cohen and colleagues have published several studies showing an increase in the polar vortex stretching or wandering. Cohen and others published a study last month attributing the cold outbreaks partly to changes from an Arctic that is warming four times faster than the rest of the globe.