Facts About the Polar Vortex and Extreme Winter Weather
Variations in the Polar Vortex Affect Weather in the Mid-Latitudes
What is a Polar Vortex?
During the winter of 2014 in the northern hemisphere we’ve been hearing about the polar vortex on weather forecasts for more than two months. But what is a polar vortex?
There are actually two polar vortices. One is over the south pole, called the Antarctic Polar Vortex and one over the north pole, called the Arctic Polar Vortex. The Antarctic Vortex is larger, stronger and more stable than its counterpart to the north partially due to less disturbance from the land mass below. The polar vortex was first described in Littell's Living Age No. 495, 12 November 1853, p. 430.
The Shore of Lake Michigan, Leelanau County, Michigan
The Four Meteorological Factors Impacting Our Weather
I have been thinking of these vortices and how they behave as a stage play in which there are multiple characters interacting. While we may think of the polar vortex phenomenon as one atmospheric condition having an effect on our weather, it is actually several different atmospheric conditions impacting one another. The results of that encounter have left us cold and under an abnormally thick blanket of snow. So here are the players in this meteorological tragedy being played out on the stratospheric stage.
- Polar Vortex-These are for all practical purposes, gigantic cyclones spinning around over the earth’s poles. The reason they are spinning is due to the rotation of the earth. This is called the Coriolis Effect. The polar vortices are massively powerful but are at their weakest after the long winter. By then, they have decayed a great deal and spend the summer recovering. In the fall, they begin strengthening for their wintertime battle with the next character in this firmamental performance.
- Anticyclones-According to weatherquestions.com an anticyclone, “also known as a high pressure area, is a large atmospheric circulation system with the wind flowing clockwise around it in the Northern Hemisphere, and counter-clockwise in the Southern Hemisphere.” These systems are created near the equator for both the northern and southern hemispheres. As summer moves into fall and fall into winter, anticyclones make their way toward their respective poles to reek havoc with the polar vortex residing there.
- The Earth’s Atmosphere-The parts of the atmosphere that come into play in this matter are the troposphere and the stratosphere. The polar vortex is located almost exclusively in the Stratosphere. It is at its widest and strongest in the higher elevations.
- Westerlies-These are the prevailing winds in both the northern and southern hemispheres and are responsible for transporting most of the earth’s weather systems. They blow from west to east.
The Earth's Atmosphere
The Lifecycle of a Polar Vortex
It is easiest to grasp how these four players interact by following the lifecycle of the polar vortex. In the spring and summer, the polar vortex is at its weakest and in its most decayed condition. In the fall, as temperatures in the stratosphere drop, the polar vortex begins to revive. By November or December in the north and by March in the south the polar vortices have fully recovered and at their highest strength. As long as the vortices remain relatively undisturbed and in place, the weather patterns, with westerly winds carrying them, proceed as normal. But it is rare when there is no disturbance in the polar vortex.
Anticyclones, The Arch Nemeses of the Polar Vortex
This is when the next characters make their entrance. Anticyclones, created near the equator, begin their northward and southward journeys in the summer, while the vortices are quiet. When the anticyclones reach the pole, they begin to interact with the vortex. These interactions are beyond my ability to understand, let alone communicate. But they are described as the anticyclones and the vortex pushing, dragging, climbing over, crawling under each other even to the point that the vortex might be separated into two or more smaller vortices. All of this activity, which can last for weeks and weeks, takes its toll on the polar vortex. It begins to weaken and to decay.
Anticyclonic Activity Over Austrailia
A Weakened Polar Vortex Leads to Colder Temperatures
This is what happened during the winter of 2012 and 2013. The Arctic (northern) vortex was weakened by the anticyclones. I know that the weathermen and ladies tell us that this is a year of a strong polar vortex, but they are speaking of its impact on weather. Extremely and abnormally cold temperatures are associated with a weakened polar vortex.
Walter Robinson, a University of Illinois professor of atmospheric sciences, has this to say about the polar vortex and its impact on weather, “When the vortex is strong, the westerlies descend all the way to Earth’s surface. This carries more air warmed by the ocean onto the land. When the vortex is weak, that’s when the really deep cold occurs.”
So we actually haven’t had a winter with a powerful Arctic/Polar vortex. It has actually been weak. But the effect of a weak vortex has been the shutdown of the westerly winds and the release of extremely cold air and huge amounts of snow.
Stratosphere, Troposphere and Westerlies
Well, our remaining characters sneaked onto the stage without being introduced. The stratosphere is where the polar vortex exists and where its annual battle with anticyclones occurs. The troposphere is where we live and where our weather patterns are carried across the landscape by the prevailing westerly winds.
The Winter of 2014
We are surrounded by a weather machine which has been designed by nature to provide for the needs of this planet. In our human judgement and in our limited understanding, we deem certain things, such as cold temperatures and amazing amounts of snow, to be bad. But these are things over which we have no control. On one hand mankind is able to have a negative impact on Mother Nature, but on the other hand, she seems to be as powerful as ever, bringing us to our knees to cry, “Enough, enough, we’ve had enough of winter, 2014.”
NASA Photo Showing Michigan With More Snow Than Any Other State in the Country as of January 29, 2014
Cold Weather Jokes: It's So Cold that....
At the request of our good friend and fellow hubber, Eric Dierker, I've added some cold weather jokes so he can vote this hub "funny."
It's so cold that...
"...hitchhikers are holding up pictures of thumbs."
"...the optician is giving away free ice scrapers with every new pair of eyeglasses."
"...pickpockets are sticking their hands in strangers' pockets just to keep them warm."
"...I chipped a tooth on my soup!"
"...if you want to hear what someone is saying, you have to grab a handful of sentences and take them in by the fire."