El Niño and the Polar Vortex Could Shape a Very Unusual Winter

The impacts of El Niño are seeping into nearly every weather pattern, with forecasters warning that its influence is going to be even more pronounced heading into the winter. One big question being pondered by climatologists is how the emergence of a Super El Niño will influence the behavior of the polar vortex. Here is what you need to know about what this means for the weather in November.

How the Behavior of the Polar Vortex Influences the Weather in the U.S.

The polar vortex is generally strong during the fall months, building up the cold air that will eventually break through and dive into Canada and the U.S. However, the latest forecast models are indicating that this traditional pattern might not be the story this year.

Forecasters are predicting that El Niño will continue to strengthen over the next few weeks. The end result will be a warmer-than-average winter for much of the U.S. How the polar vortex responds to this climate phase will significantly influence what type of winter is in store.

The polar vortex is the term used to describe the zone of fast-moving winds whipping around the Earth's poles. While this vortex always exists, it is primarily during the winter that it drives the weather across the U.S. The periodic outbreaks of Arctic air that spread over the U.S. during the winter are the result of an unstable polar vortex.

A sudden temperature increase in the stratosphere thousands of feet above the Earth's surface is known as a "Sudden Stratospheric Warming" event. These events unfold when the typically stable vortex is disrupted, allowing the bottled-up cold air to escape its normal resting place.

These Sudden Stratospheric Warming events work by stretching the polar vortex away from the pole. This movement drags the core of the coldest air to the south, sending it spilling into the northern U.S.