Originally Published: 02 FEB 23 03:06 ET

Updated: 02 FEB 23 11:38 ET

By Holly Yan, Monica Garrett, Aya Elamroussi and Joe Sutton, CNN

(CNN) -- Dangerous wind chills as cold as 50 degrees below zero will blast the Northeast while parts of the South struggle to thaw from a deadly ice storm.

The mind-numbing wind chills set to wallop New England "could be the coldest felt in decades," the Weather Prediction Center said.

More than 15 million people are under wind chill warnings or advisories in the Northeast. The alerts begin to go into effect very early Friday morning and last through Saturday afternoon.

"This is an epic, generational Arctic outbreak," said the National Weather Service in Caribou, Maine. "The air mass descending on the area Friday into Friday night is the coldest air currently in the Northern Hemisphere."

Such extreme conditions can cause frostbite in as little as 10 minutes.

Fortunately, the brutal blast will only last about 36 hours. Temperatures across most of the Northeast are expected to rise by Sunday afternoon.

But farther south, cities paralyzed by a deadly ice storm this week will get an encore of nasty weather before finally thawing out this weekend.

Here's what to expect in the South and Northeast:

One more wave of ice and misery in Texas

The ice storm linked to at least three deaths in Texas will dump more freezing rain Thursday morning.

Another quarter inch of ice could glaze central and northern Texas, as well as southern Oklahoma and Arkansas.

Adding to the misery: More than 400,000 homes, businesses and other power customers had no electricity Thursday morning, according to PowerOutage.us. Most of the outages are in the Austin area.

Another 60,000 customers in Arkansas, 20,000 in Mississippi and 20,000 in Tennessee also had no power in the brutal cold Thursday morning.

But temperatures will warm above freezing in much of the region by noon Thursday.

Boston could feel like it's 27 degrees below zero

More than 15 million people will be under wind chill alerts starting Friday as sub-zero temperatures and ferocious winds target the Northeast.

"The wind chills are something northern and eastern Maine has not seen since similar outbreaks in 1982 and 1988," the weather service said.

The alerts cover all of Maine, New Hampshire, Vermont, Massachusetts, Rhode Island and Connecticut. They also include northern New Jersey, northeast Pennsylvania and much of New York state outside of New York City and Long Island.

The bitter cold is expected to move into the region Friday morning, and the coldest temperatures are expected Friday night and Saturday morning.

Temperatures will plummet below zero degrees Fahrenheit in much of New York state and New England. In northern New York and northern New England, temperatures will dip to 15 to 25 degrees below zero.

But vicious winds will make the air feel even colder -- with wind chills plunging to -35 to -50 degrees in northern New York state and northern New England.

"Avoid any outdoor activities on Friday and Saturday!" the New Hampshire Homeland Security and Emergency Management posted on Facebook. "Cold temperatures paired with the wind chill factor could lead to potentially life-threatening conditions outdoors."

New York City could endure wind chills as low as 10 degrees below zero.

And in Boston, where the air will feel like it's 27 degrees below zero, the mayor declared a cold emergency for Friday through Sunday.

"I urge all Boston residents to take precautions, stay warm and safe, and check on your neighbors during this cold emergency," Mayor Michelle Wu said.

Connecticut Gov. Ned Lamont activated the state's severe cold weather protocol, starting at noon Thursday and lasting through the weekend.

"With the kind of severe cold weather that is headed our way, frostbite can develop on exposed skin in under 30 minutes," the governor warned.

"Spending long periods of time outdoors in these conditions is not only harmful, it can be fatal."

Shelters and warming centers are available across Connecticut, and transportation can be provided when needed, said Lamont.

Warming centers are also expected to be available in Maine, Rhode Island, Massachusetts and Vermont, officials said.

The agony won't last long, though. High temperatures across the region will rise 20 to 30 degrees between Saturday and Sunday.

In fact, most of the Northeast -- except northern Maine -- will actually be above normal Sunday, with high temperatures reaching the 30s and 40s.