New Delhi, Nov. 20 -- High above the North Pole, in a largely overlooked part of the atmosphere, a major shift is taking shape. Over the next 10 days, developments in the stratosphere are expected to reshape global weather patterns and may pave the way for a colder, snowier December across sections of the Northern Hemisphere.

Several parts of the United States, currently enduring record-breaking heat just days before Thanksgiving, could soon see a dramatic reversal. Scientists say this could be one of the earliest significant disruptions to the polar vortex since satellites began monitoring it.

Think of the stratospheric polar vortex as a fast-moving ring of wind that keeps the frigid Arctic air contained at the top of the world. When t...