A polar vortex is slated to sweep most of the continental US bringing winter storm warnings and a hazardous freeze to millions.

The polar vortex is a ring of cold air that typically circles the Arctic. A strong jet stream essentially acts like a fence, keeping it locked there. If there's any weakening in the jet stream (the fence), the frigid air can become unstable and spill out. This sends the normally trapped cold air much farther south.

The most unusually cold air in the Northern Hemisphere will be over the United States early next week, bringing dangerously frigid conditions.

A polar vortex is currently hitting the United States, with schools closed in many areas and at least four deaths caused by treacherous conditions.

A lobe of the polar vortex, a stormy ring that typically keeps the coldest air locked up near the North Pole, will dip southward into the United States this weekend into next week. Polar air ...

Despite a cold start to the day, most of the U.S. will experience seasonably mild temperatures on Thursday. However, dangerous changes are on the way as a polar vortex tightens its grip on the nation as sends temperatures tumbling below freezing starting this weekend.

A series of cold fronts the last few weeks has kept Florida downright chilly, as another winter storm starts to take aim this weekend

Americans were bracing Thursday for frigid temperatures that forecasters said could produce life-threatening conditions, with Donald Trump's inauguration expected to be the coldest in 40 years.

A dangerous and potentially life-threatening stretch of cold weather has much of the U.S. on alert as a lobe of the polar vortex invades the nation and sends temperatures tumbling to levels not seen in years.

Over 120 million Americans will face extreme cold, with temperatures potentially reaching minus 40 degrees Celsius. Meteorologists warn that it will be colder than in Greenland. Due to the frigid weather,

Models are hinting at the possibility for snow, freezing rain, and ice pellets to fall from central Texas across the northern Gulf Coast into portions of northern Florida. While the setup looks favourable for snow and ice, it’s extremely hard for wintry precipitation to fall in this part of the world.