Have you noticed that this winter seemed colder than normal? Well, if you have, you're correct! Much of the nation has seen temperatures much below normal this winter, along with much of Europe. With cold air outbreaks reaching all the way down to the gulf coast (Florida saw some record low temperatures!) and massive snow storms slamming the East Coast, this has been a rather harsh winter! And it's very comparable to the 2009 - 2010 winter. So what has caused such harsh winter conditions? Scientists at NOAA (
National
Oceanic and
Atmospheric
Administration) have developed a theory that it's due to the break down of the Polar Vortex - a strong wind flowing around a center of low pressure typically found in the arctic during the winter months. The Polar Vortex actually acts like a wall that keeps cold air over the arctic, "protecting" the rest of us for cold air outbreaks. What the scientists have found thus far is rather interesting! Observations have shown that the Polar Vortex has been broken to some extent during the past two winters, allowing for the cold air north of these strong winds to flow southward over the North American and European continents.
"In December 2009, the Arctic was 9 degrees F
warmer than normal, and mid-latitude continents were 9 degrees F
cooler than normal, with record cold and snow conditions in northern Europe, eastern Asia and eastern North America,” says Dr. James Overland, a scientist at NOAA’s
Pacific Marine Environmental Laboratory (PMEL) in Seattle. “This is the Warm Arctic-Cold Continents pattern. The winter of 2009–2010 had especially extreme weather in the U.S. as moisture from El Nino hit cold air
from the Arctic.”
But why are we seeing this trend now? Some evidence points to the loss of sea ice in the arctic allowing the ocean below to warm the atmosphere, which could potentially break down the cycle by affecting weather patterns such as the North Atlantic Oscilation (this is the normal climatic pattern which dictates the winter climate from central North America to Europe. However, there is still a lot unknown and more research is being done. But if this cycle keeps up, we may need to get use to more cold winters around the nation!
