Scientists have noted that a year-round phenomenon above each of the globe’s poles have shown recent signs of shifting and even disruption, leading to potentially significant impacts on climate patterns.
The polar vortex is generally an area of low pressure above the Earth’s poles that contains the coldest air.
The vortex is more influential during a hemisphere’s winter than in the summer months because of a more pronounced temperature gradient between what is considered to be mild and downright cold.
Events that are known as stratospheric warming, changes in the jet stream and even significant changes in pressures and temperatures can lead to alterations in the pattern and even a full disruption.
During the summer, the polar vortex is considered to be in an expanded state, which in part limits cold air intrusions, southward or northward – depending on which pole is in view.
Satellite observations and model forecasts show zonal winds being fairly weaker than what is typical for September and October.
Without a tight belt of winds concentrating the cooler air around the Arctic, cold air masses will tend to escape and head south in lower latitudes.
Countries such as Canada, the United States, Russia and the nations that make up the continent of Europe that lie south of the Arctic could see the chances of a normal-feeling fall or even a cooler than average season become greater than they would otherwise typically be.
The status of the winds is the weakest in many years, meaning someone in the Northern Hemisphere will likely be the beneficiary of a chilly fall, but exactly who will be dependent on other weather features.
The weakening of winds around the North Pole or even significant disruption of the Polar Vortex does not guarantee a cold air invasion. Features such as high low pressure systems as well as the jet stream act as conveyor belts for the air masses and can prevent a cold air intrusion or help usher one in.
Disruptions to the vortex are known to happen several times during the winter months but can vary depending on the vortex’s strength.
