(CNN) -
Just after midnight on Tuesday it was hotter than it will be all day in the Northeast.
Since then, the temperature has been dropping, and it will remain dangerously cold throughout the day in the region, leaving major cities like New York and Boston with the coldest daytime air mass in nearly three years.
When the sun rose over New York on Tuesday morning, it had already dropped to -12 ° C from a starting point of -5 ° C.
And even if the sun tries to warm the most populated city in the country, the temperature will have a hard time reaching -6 ° C.
"Highs this afternoon will struggle to get out of -12 ° C and -6 ° C in most places, with temperatures in the single digits in northern New England," the Weather Prediction Center said.
In Boston, the temperature dropped to the single digits on Tuesday morning and will barely return to -12 ° C in the afternoon.
"Dangerous cold through southern New England today as Arctic air invades," the Boston office of the National Weather Service said Tuesday.
The worst part is that it feels even colder than the thermometer reads.
advertising
Why does it feel colder
Wind chill in Boston was -23 ° C just before 9 a.m. ET on Tuesday.
Both New York and Boston are flirting Tuesday morning with temperatures that "feel" close to freezing or lower.
"Feel" refers to how temperature and wind work together to make you feel colder than it would be without wind;
this is also known as a wind chill.
As the wind increases, it draws heat from the body, causing the temperature of the skin to drop, and eventually the internal temperature of the body.
Therefore, the wind makes it "feel" much colder.
The strong winds will continue to make it colder throughout the day on Tuesday before easing off overnight.
"The strong winds will add an additional touch to the cold snap, with a generalized wind chill below zero throughout the region and down to 40 below zero in northern Maine," the forecasting center said.
Exposed skin is at risk of frostbite in as little as 10 minutes when wind chill temperatures are this low, the Weather Service office in Gray, Maine, said.
More than 6 million people were on a wind chill alert Tuesday morning from New York to Maine, where the temperature "feels like" life-threatening.
Although frostbite may take longer to develop in slightly warmer southern states, it is very important to continue to take precautions to stay safe.
"Venturing into this cold weather requires a plan to stay safe for yourself and your pets," said CNN meteorologist Chad Myers.
"Shorter walks, lots of layers, and a cold weather kit for your car are always things to consider. Even indoors, it's time to prevent frozen pipes."
What to bring in the car during bad winter weather.
Do you wonder where this cold comes from?
Here's a hint: it's cold and icy, and it sits above the Arctic Circle.
In fact, the air mass in Boston was traced to Utqiaġvik (formerly Barrow), Alaska, by meteorologists from the Boston Weather Service bureau.
[Arctic blast] Alright folks, we all know by now it is going to get VERY #cold tomorrow with a forecast high of 11 ° F in Boston.
So when we ran the backward trajectory model, we can trace the air all the way to Utqiaġvik (formerly Barrow), Alaska!
@NWSFairbanks #MAwx #RIwx #CTwx pic.twitter.com/vHwY46bBdK
- NWS Boston (@NWSBoston) January 10, 2022
"Fortunately, this blast of cold air will not stay long, as the most stable temperatures between -1 ° C and 4 ° C arrive this Wednesday afternoon," the forecasting center said.
But even that relief could be brief.
"Although there will be a few brief warmer days," Myers said, "the overall pattern predicts that the jet stream and associated cold fronts creeping up from the Arctic will last at least the next two weeks."
This will keep most temperatures in the eastern US well below average and the western US well above the remainder of this month.
"The duration of the arctic blast is as important as the cold air itself," Myers explained.
"This kind of prolonged cold snap puts everything to the test, from municipal services to water pipes."
- Monica Garrett, CNN meteorologist, contributed to this report.
cold wave