(CNN) — It was warmer just after midnight Tuesday morning than it will be all day long in the Northeast.
Since then, the temperature has been dropping, and it will stay dangerously cold all day in the region, leaving major cities like New York and Boston with the most frigid daytime air mass in nearly three years.
As the sun rose Tuesday morning over New York, it had already dipped into the teens from a starting point of 23 degrees. And even as the sun tries to heat the nation’s most populous city, the temperature will strain to get back up to 20.
“Highs this afternoon will struggle to make it out of the teens and 20s for most spots, with single digits found across northern New England,” the Weather Prediction Center said.
In Boston, the temperature dipped down into the single digits Tuesday morning and will barely make it back into the teens by afternoon.
“Dangerous cold across southern New England today as arctic air invades,” the Boston office of the Nation Weather Service said Tuesday.
What’s worst is that it feels even colder than the thermometer reading.
Why it feels even colder
New York and Boston are both flirting Tuesday morning with “feels like” temperatures around zero or below.
“Feels like” refers to how temperature and wind work together to make it feel colder than it would be with no wind; it’s also known as wind chill.
As the wind increases, it draws heat from the body, driving down skin temperature — and eventually internal body temperature. Therefore, the wind makes it “feel” much colder.
Stiff winds will continue to make it feel colder throughout the day Tuesday before easing overnight.
“Blustery winds will add an extra bite to the cold snap, with widespread wind chills below zero throughout the region and as low as 40 below zero in northern Maine,” the prediction center said.
Frostbite on exposed skin may occur in as few as 10 minutes when wind chill temperatures dip this low, said the weather service office in Gray, Maine.
Over 6 million people were under wind chill alerts Tuesday morning from New York to Maine, where the “feels like” temperature was life-threatening.
While it might take longer to develop frost bite in states further south that will be slightly warmer, it is very important to still take precautions to keep yourself safe.
“Venturing out in this cold weather requires a plan to stay safe for you and your pets,” CNN meteorologist Chad Myers said. “Shorter walks, many layers and a cold weather kit for your car are always things to consider. Even indoors, it is time to prevent frozen pipes.”
Wondering where this cold came from? Here is a hint: It is cold and icy and sits above the Arctic Circle.
Indeed, the air parcel in Boston was traced all the way back to Utqiaġvik (formerly Barrow), Alaska, by meteorologists at the Boston weather service office.
“Fortunately, this punch of cold air won’t hang around long as more seasonable temperatures into the upper 30s and 40s arrive by Wednesday afternoon,” the prediction center said.
But even that relief might be brief.
“Although there will be a few brief warmer days,” Myers said, “the overall pattern has the jet stream and associated cold fronts barreling in from the Arctic for at least the next two weeks.”
This will keep most eastern US temperatures much below average and the western US well above for the remainder of this month.
“The duration of the Arctic blast is as important and the cold air itself,” Myers explained. “This kind of extended cold snap puts a strain on everything from city services to your water pipes.”
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