The Point Everyone Is Missing About the Return of the ‘Polar Vortex’

“We’ve got this cool air coming down over the eastern half of the country, and that’s gonna just be kind of nice,” said Jennifer Francis, an atmospheric scientist and research professor at Rutgers University’s Institute of Marine and Coastal Sciences.  “But along the east coast, we’re looking at storms and floods.  On the west coast, we’re looking at heat and fires.  And it’s all part of this jet stream pattern.”

A particularly wavy jet stream is what is causing the so-called “polar vortex,” or cold air from the Arctic, to travel down to the United States, Francis said. The dramatic and unusual southward swoop, shown in the map on the right, allows air from the cold north to travel south.  The same thing happened this past January, when a dramatic southward swing of the jet stream brought increased cold air to an already-freezing region.  That was big news, extreme weather-wise.

Now, the “polar vortex” is making for fairly mild weather.  But at the same time, that same wavy jet stream is swinging northward in the western United States, bringing increased heat to an already-dry and wildfire-stricken region.  Extreme weather-wise, Francis says, this is a bigger deal.

The Point Everyone Is Missing About the Return of the ‘Polar Vortex’