BALTIMORE — Something unusual is developing high above the Arctic, and it could affect Maryland’s weather heading into winter. The latest European and American models show a significant disruption of the Polar Vortex around November 4 to 6. Normally, the Polar Vortex should be strengthening this time of year. A weaker vortex could eventually help push colder air into eastern North America, possibly supporting an early December snow window for Baltimore.
What Is Happening to the Polar Vortex
The Polar Vortex is a large area of cold air and strong winds that circles the North Pole about 20 miles above the ground, in the stratosphere. In late fall, it usually grows stronger as the Arctic gets darker and colder. A strong vortex tends to keep the coldest air locked up near the pole.
This year, models show the vortex weakening and stretching out instead. Forecast maps show the circulation pushed off the pole, with a large warm area building over the Arctic. Winds around the vortex at 60 degrees north are forecast to slow down well below their usual strength in early November.
Cold Air Could Spill South
When the Polar Vortex weakens or gets disrupted, cold Arctic air can break loose and spill south. Forecast maps show a large pool of very cold air over Canada in the days that follow. That cold air could eventually move into the United States, depending on the jet stream pattern.
The big question is where that cold air goes. It could drop into North America, Europe, or Asia. A weaker vortex does not guarantee cold weather for Maryland, but it raises the odds of colder outbreaks later on.
Effects Take Time to Show Up
Changes in the stratosphere do not affect weather at the surface right away. It can take one to three weeks or longer for a weakened Polar Vortex to influence the jet stream. That means the main effects would likely show up in late November or early December…