(CNN) — More than 50 million people are under alert due to a dangerous system that makes its way from the central United States to the south and then to the northeast in the next 3 days.
A low pressure system currently in the Central Plains region will begin to enter the lower Mississippi Valley region on Friday night. On Saturday, that low will slowly meander through the southeast before finally heading north along the eastern seaboard.
Rain, snow, sleet or freezing rain – how about all of that in a span of 24 hours? That will be the case for some states this weekend.
So, let’s break down the potential dangers in each region.
Snow Forecast: Check these maps to see how much snow is expected in your area.
Upper Midwest to Middle Mississippi Valley
The storm will move through parts of the Midwest and the Middle Mississippi Valley today, dropping up to a foot of snow.
Winds will also pick up in these regions, leading to blowing snow and poor visibility.
“Impacts to travel are expected to be significant at times, especially during afternoon school outings and overnight commutes,” the National Weather Service (NWS) office in Des Moines said.
Heavy snow will fall in parts of the Dakotas, Iowa and Minnesota with 6 to 12 inches of snow expected.
From there, the system will dip farther south, heading into Missouri, Arkansas, and Kansas.
“How quickly surface temperatures drop below freezing, and thus how quickly rain turns to snow, will play a big role in determining how much snow accumulates,” the NWS office in Topeka, Kansas said.
The southeast has a mix of everything
For much of the southeast, this system will start as rain on Saturday. As temperatures drop, that rain will turn to freezing rain, sleet, and eventually snow in many places.
Forecasting winter weather in the Southeast is never easy, as the weather is often short.
“These different types of winter precipitation are very sensitive to small changes,” said Kyle Thiem, a meteorologist with the NWS office in Atlanta. “A change of just one or two degrees can mean the difference from relatively harmless rain to shocking accumulations of ice and snow.”
However, it is the slow forward speed of this system that provides the setting for a crippling ice storm that could leave millions without power.
The Carolinas will be the most likely area to experience the ice, with cities like Charlotte and Columbia accumulating up to 1.2 centimeters of ice which, along with high winds, will bring down trees and power lines.
The NWS office in Greenville, South Carolina is warning that ice dams will become very dangerous along and east of I-85, including Spartanburg, South Carolina, to Salisbury, North Carolina. This includes the entire Charlotte metro area.
In the southern Appalachian Mountains, snow totals will increase as fast as elevation. Asheville, North Carolina, for example, is forecast to rise 20 to 30 centimeters, but could top out at 50 centimeters at elevations above 1,200 meters.
The winter storm in the mid-Atlantic and northeast
The winter storm will head to the East Coast on Sunday and Monday, with heavy snowfalls of more than 12 inches expected in some places.
Some snow will fall in the major metropolitan areas of Washington, Philadelphia, New York and Boston, but a change in rainfall will stop the accumulations.
“At this time, the most likely scenario is a heavy flurry of snow in the front end as the storm moves into the region on Sunday afternoon, followed by icing overnight and single rain possibly for areas near and beyond. east of I-95,” the NWS office in Baltimore said Friday morning. “At this time, icing is not expected to reach our far western areas, where heavier snow of 12 inches or more is possible.”
Cities like Charleston, Pittsburgh, Buffalo, Syracuse and Burlington, Vermont will see the heaviest snow.
What helps the Northeast is that long before most of the snow arrives, there will be very cold air and dangerous wind chills.
Wind chill alerts are in effect for more than 20 million people this Friday and Saturday as temperatures could drop as low as 40 to 42 below zero across much of inland New England.
“Dangerously cold wind could cause frostbite on exposed skin in as little as 10 minutes,” warns the NWS.
CNN Meteorologists Chad Myers, Dave Hennen and Monica Garrett contributed to this story.