More than 65 million people in parts of the central and eastern third of the country had been notified of winter weather as of Saturday afternoon, the National Weather Service said.
The storm will move Saturday night and Sunday in a southeast direction with rain, freezing rain and snow before moving into Sunday northeast on Monday.
And freezing rain and ice in the Southeast and Mid-Atlantic regions could cause the biggest trouble on Sunday.
“This is going to be the biggest problem we’ve got over the next 48 hours – frost and lots of it,” said CNN meteorologist Allison Chinchar.
Areas north of Georgia and Virginia could see up to half an inch of ice, and parts of North and South Carolina could see three-quarters of an inch or more of ice, forecasters said.
High winds, along with “the weight of that ice on trees and power lines, have the potential to cause widespread power outages,” Chinchar said.
The governors of Georgia, North Carolina, South Carolina and Virginia have declared states of emergency, allowing resources to be deployed before the storm arrives.
Snow is also expected to affect some southern cities on Sunday, endangering travel in places like Memphis, Nashville, Atlanta and Charlotte.
More than a foot of snow is possible Sunday through Monday from the southern Appalachians into the inland Northeast.
Heavy snow – including 8-14 inches in some areas – fell Friday through Saturday morning in parts of the Dakotas, Minnesota and Iowa.
From there, the system travels to Missouri, Arkansas and Kansas, where it rained and snowed on Saturday. Heavy snowfalls are expected in the Mid-South and Tennessee Valley throughout the day.
Local areas of Tennessee could see more than 6 inches of snow Saturday through Sunday.
Southeast can have a combination of everything
For much of the Southeast, the system will start as rain on Saturday.
As temperatures quickly drop after a strong cold snap, the rain will turn to freezing rain, sleet and eventually snow in many locations across the Southern Appalachians on Saturday night.
Georgia Governor Brian Kemp ordered the State Department of Defense to prepare 1,000 National Guard troops to assist in the storm response.
In South Carolina, Governor Henry McMaster urged residents to monitor local weather forecasts and take precautions.
The system is expected to move slowly, forming a crippling ice storm that could power out millions of people from northeastern Georgia to southern Virginia from Saturday night into early Monday morning.
Cities including Charlotte, Greenville, Winston-Salem and Greensboro are forecast to see a quarter to a half inch of ice build-up over the course of Sunday night, along with gusts of up to 40 mph possible could knock down trees and power lines in the area.
The National Weather Service has issued an ice storm warning for parts of South Carolina, effective early Monday, with temperatures likely to remain below freezing through early next week.
In the southern Appalachian Mountains, total snowfall will increase as quickly as altitude. For example, Asheville, North Carolina, is forecast to grow 8-12 inches, but could reach 20 inches at elevations above 4,000 feet.
Mid-Atlantic and Northeast
The storm will turn northeast to the East Coast on Sunday and Monday, with more than a foot of snow expected in some locations.
Some snow will fall in major metro areas of Washington, DC, Philadelphia, New York and Boston, but the change to rain will reduce the amount of snow that accumulates.
Snowfall in the area may be thick enough to avoid significant freezing, but NWS Baltimore warns that untreated surfaces can still lead to hazardous travel conditions as ice accumulates.
Most of the accumulated snowfall will occur from Sunday afternoon through Monday morning.
Inland cities such as Charleston, Pittsburgh, Buffalo, Syracuse and Burlington, Vermont, will see the heaviest snowfall.
Before the phenomenon of snow moving into the area, the Northeast region will experience intense cold temperatures and dangerous cold winds.
The wind chill warning will be in effect for nearly 20 million people on Saturday, as temperatures could drop to 40 to 45 below zero in parts of the Northeast.
Along with the possibility of snowfall, strong easterly winds combined with a storm system could cause major coastal flooding up to 3 feet above ground in some areas along the Northeast coast during high tide. .
The timing of winds changing from east to south will largely determine flood severity, with a moderate chance of flooding if winds change direction before high tide.
Localized moderate to large-scale flooding in vulnerable areas near waterfronts and coastlines, including roads, parking lots, parks, said the NWS in New York. , lawns and houses and businesses with basements near the waterfront”.
Flooding can cause road closures and structural damage along the Atlantic coast.
CNN meteorologists Allison Chinchar, Chad Myers, Dave Hennen, Monica Garrett, and Haley Brink contributed to this story.