With the Northern Hemisphere well into the winter months, it may seem like temperatures are cold enough already. However, a deep freeze, thanks to the polar vortex dipping down from Siberia, is about to bring even harsher arctic blast to nearly 300 million Americans starting this weekend. Maps show where and when the cold front will arrive.
The polar vortex is a large area of cold air and low pressure that normally spins over the North and South Poles. During the winter months and when the jet stream allows, this cold air can drop farther down into lower latitudes like in the United States. This is forecast to happen as soon as this weekend.
