"The polar vortex is not a recently discovered phenomenon; in fact, it has been talked about in the meteorological world for decades," AccuWeather.com Senior Meteorologist Bernie Rayno said.
A polar vortex is a large pocket of very cold air, typically the coldest air in the Northern Hemisphere, which sits over the polar region during the winter season.
The frigid air can find its way into the United States when the polar vortex is pushed farther south, occasionally reaching southern Canada and the northern Plains, Midwest and northeastern portions of the United States.
A large, powerful high pressure system originating in the Eastern or Western Pacific and stretching to the North Pole is required to displace the pocket of cold air.
"These high pressure systems can reach Alaska, but it is not typical to stretch all the way to the North Pole," according to AccuWeather.com Senior Meteorologist Brett Anderson.
The vortex is capable of delivering subzero temperatures to the United States and Canada for several days at a time.
When the strong air from the Eastern or Western Pacific weakens and falls apart, the polar vortex will retreat into place near the North Pole.
Tropical moisture from a system moving up the US East Coast could help to enhance rainfall and bring gusty winds to New England and Atlantic Canada this weekend.
Typhoon Haima made a second landfall in southeastern China on Friday after leaving at least seven dead in the northern Philippines.
A dramatic change to colder weather, and in some cases a taste of winter with snow, will take place into this weekend.
Powerful solar storms can devastate the world's interconnected power grids, airline operations, satellites and communications networks.
Many places received the first snowfall of the season as storms rolled through the northwestern U.S.
Orionid meteors will streak across the night sky as the shower is set to peak late this week.
Winds aloft and from Hurricane Juan carried African locusts across the Atlantic to Dominica, St. Lucia, Jamaica and five other islands.
Tallahassee, FL (1989)
30 degrees, tied October record low.
State College, PA (1995)
3.65" of rain.