Essential Pittsburgh
2:48 pm
Wed January 8, 2014

Why the Wacky Weather? The Polar Vortex Explained

Tuesday caused Pittsburgh to hit a record low of -9 degrees, but science expert, John Radzilowicz, may have the answer to why it happened.
Tuesday caused Pittsburgh to hit a record low of -9 degrees, but science expert, John Radzilowicz, may have the answer to why it happened.
Credit artnoose / Flickr

From mild, rainy, and in the 40's Sunday, to an all-time record low of -9 Tuesday to 50 degree temperatures by end of the week. Pittsburgh is experiencing unprecedented temperature fluctuations and weather patterns. The question is what’s going on with this wacky weather. John Radzilowicz, science expert and director of professional development at ASSET-STEM, believes he has the answer.

“As the earth spins above both polls, there is a certain column of air that basically gets trapped in that area of the poll and goes west to east with the rotation of the earth (those areas, of course, are normally extremely cold, so that air becomes very, very cold) and as it spins around the pressure in that airdrops. The air surrounding it is generally warmer and has higher pressure and it is almost like a fence that holds these pockets of air above the poles and that's one of the reasons that the poles can be so brutal in terms of their weather. What’s happened is that little pocket, that normally stays within that fence, well we’ve knocked a few holes in that fence.

What’s happened is, we’ve seen that in the arctic over the last several years, a dramatic drop in the amount of ice that we see when we get into the summer months, in fact in 2012 we set a record again for the least amount of ice. We’re basically losing all this ice and what happens is more moisture and more energy enters the atmosphere. So during those summer months more moisture and energy is building up and when the winter comes around, we don’t quite the low that we need to hold that air confined in the fence. Instead its pressure goes up, the pressure of the surrounding air comes down a little bit and now the fence becomes permeable, there’s nothing to bump up against and so it begins to move more easily out of that area, so it becomes super cold in the north and then it can slide down over Europe, over North America and get pushed back up again.”