The Polar Vortex Demystified

27 February 2014

Every year it seems that some weather term gets picked up, misassociated, and eventually butchered by the media. A few years ago it was derecho, this year its now the dreaded Polar Vortex.

I’ve already lost count of the number times in the past week that I have heard…

“Is the polar vortex coming back?”

“I’m so sick of this polar vortex!”

“Are we going see the polar vortex tonight?”

And my favorite…
“I hate this cold and wind. The polar vortex messed up my hair.”

So what is this polar vortex and why is it making everyone who hates winter miserable this year? Let’s start with this:

The polar vortex is not new, a storm, at the Earth’s surface, or directly observable.

So what is it?

Time for a quick meteorology lesson.

The polar vortex is an area of circulation located in the upper atmosphere over both poles. It contains pool of cold air surrounded by very fast winds that keep it  contained over a generally small area.

It occurs because of the Earth’s spin and the temperature different between the poles and the equator. This is why it’s most notable during winter months when the temperature difference between the equator and poles is greatest.

The best way to think about the polar vortex is that the pole is a drain in the bathtub sucking in all of the cold air.

Screen Shot 2014-02-26 at 10.02.29 PM
This shows the polar vortex surrounded by strong winds high in the atmosphere.

Why is it “here” in the United States now?

Technically it is not. Depending on the strength of the polar vortex, one of two things can occur.

During a year with a strong polar vortex, winds high in the atmosphere are strongest and most of the hemisphere experiences a more regular pattern of storminess. This also keeps the coldest of the air over the poles most of the time.

When the polar vortex is weaker, the colder air that is trapped over the poles can sneak away easier and drift further south.

Yes, a “weak” polar vortex is what is causing the colder weather over the United States.

So are we actually directly dealing with the polar vortex in Minnesota and Georgia? No.

What we are experiencing is some of the air from over the poles being dragged into our lives by the jet stream. If the polar vortex was actually over Georgia, there would be something seriously wrong with our planet. This picture below shows exactly how it happens:

This is how the polar vortex winds weaken and allow a piece of cold air to drift southward.

So is this new?

Not at all. There have been many occurrences of this recorded in history, most notably in January 1985 where many of the records we are nearing today were set.

However, climate change over the past few decades has lead to less polar ice and a warmer Arctic and Antarctic in general. This means on average we will see a smaller temperature difference between the equator and poles during the winter months. Which, as we just learned, means a weaker polar vortex, and better chance of cold air wandering south.

But does that mean this this going to happen every year? Most likely not. We will just see these extreme events happening more often.

But seriously, when is it going to end?

Eventually the sun will rise over the Arctic, temperatures will start to rise, and spring will be upon us.

However, in the short term is a matter of plain old weather forecasting. Just like how we forecast rain for the next week, we forecast these pieces of cold air that wander south. We could see another few weeks, we could have another month or two, only time will tell.

But honestly, I am not too worried. Weather changes. And I know everyone will be complaining it’s too hot outside soon enough.

I hope this better educated you about what the polar vortex is and is not. Because next time you see a meteorologist, please don’t blame your bad hair on it.

Have any further questions? Feel free to contact me.

Wind image credit: Earth Map by NullSchool