What’s with this weather?

December starts without snow

Graphic by: Jordan Lodge | Production Manager

Despite recent snowfall, December started with bare trees and green grass this year, a rare sight for Michigan residents that has many puzzled.

Most Michigan residents, who are used to harsh winters, are wondering why they haven’t had to use their snow shovels yet, and when they have, why it hasn’t stuck. According to Ferris professor of geology Jennifer Johnson, the answer is not simple.

“This particular year, what’s going on is really kind of a lining up of a couple different weather events, not long-term changes but just individual short-term things,” Johnson said.

Many climatologists believe that the three main factors for the outcome of a Michigan winter are the polar vortex, warmer oceans and lake effect snow, according to Johnson, who defines the polar vortex as a cold pool of air confined by jet streams above the Arctic.

When the winds of the jet stream weaken, the polar vortex can break into smaller groups that can move away from the arctic, according to Johnson.

“So instead of having this nice, confined pool of cold air over the arctic, what you have are smaller, little batches of cold air and these weaker winds are allowing that cold air to wander away from the Arctic a bit and this happens every year, we get the polar vortex anytime we have exceptionally cold temperatures in the winter for a short time,” Johnson said. “It’s a sign that the polar vortex has allowed some of that cold Arctic air to kind of come down into Michigan.”

As for warmer oceans, the National Snow and Ice Data Center has reported a record low satellite record of Arctic Sea Ice Extent, which means that there is more open water in the Arctic than usual.

“So because the Arctic ocean has more open water than normal, that means more of it is able to evaporate into the atmosphere, so there’s more humidity in the atmosphere,” Johnson said. “If you look over what’s been going on in Siberia, they are having exactly the opposite kind of year that we are. They are much colder than normal, they’re getting way more snow than normal. That’s because of all that extra moisture and because the polar vortex has moved itself right over Siberia.”

According to Johnson, if the polar vortex moves over Michigan, the Great Lakes are warm enough this year to create lake effect snow in Michigan.

These factors and how they work together will contribute to the upcoming winter. However, it’s too early to make any precise predictions, according to Johnson.

For more information, visit nsidc.org.