According to the Washington Post, experts believe that a sudden stratospheric warming event could affect the polar vortex. If strong enough, it could weaken and force the vortex off of the North Pole, causing pieces of it to split in two and make its way south. The polar vortex is the circulation of air around low pressure that acts as a repository for some of the coldest air on the planet. If it were to travel south, it would create extremely cold winters for Northern Europe, Asia, and North America—including the United States.
Winds in the polar vortex normally circulate from west to east around the North Pole. But, rapid warming has forced the winds to sack. The temperatures could even force the winds to reverse, which will increase the chances of the vortex breaking off and traveling south. This could lead to colder temperatures, harsher winds, slower-moving snow storms, and more.
Although it's not confirmed, the polar vortex could already be splitting due to a stratospheric temperature spike. Now, seasonal forecasters like Judah Cohen of Atmospheric and Environmental Research in Massachusetts are trying to accurately predict how winter weather may ensue in the United States by tracking to see how events in the stratosphere impact the troposphere (the layer of the atmosphere where most of the weather occurs).
While this might be significant news, Cohen understands that this doesn't matter unless it impacts people. He also notes that the conditions between the stratosphere and troposphere are not well understood. As an example, he explained that similar warming occurred last year and the polar vortex stayed intact.
"No one is going to care until there is snow in people’s backyards," Cohen said.