Crozet Weather Almanac: January 2018

Chart courtesy Heidi Sonen and Roscoe Shaw.

Do Not Fear the Polar Vortex

The “polar vortex” has been in the news a lot lately. Actually, Heidi and I never heard of such a thing in our younger days. We called it the “jet stream,” which I’m sure you have heard about. Recently, it has become trendy to refer to it as the polar vortex and make it seem new and scary.

At the end of January, a particularly bad cold outbreak moved south out of Canada and brought near all-time record cold to Minnesota, Illinois, Iowa and Wisconsin. Trust me, all-time record cold in Minnesota is serious business. The coldest of the air missed us but we still got down to 6 degrees on the last day of January.

Not only did the polar vortex bring near-record cold, but it also brought near-record stupidity in the climate change war of words. Some were quick to use this bitter cold as evidence that global warming was all a “hoax.” The other side had the audacity to claim that global warming is now causing more extreme cold outbreaks because fossil fuel use has messed up the normal flow of the jet stream. As usual, both extreme sides are dead wrong.

First of all, the cold air outbreak covered about 1% of the earth for about three days so it is completely irrelevant to global climate which covers the entire earth and is measured over periods of decades. Using this cold outbreak to claim the earth isn’t warming is just silly, not to mention, wrong.

Equally absurd is the claim that the polar vortex is bringing more extreme cold outbreaks now because of climate change. That can be easily tested by crunching the numbers. Winters in the U.S. have warmed steadily since the 1970s. If this claim was true, then cold outbreaks would be just as bad or worse despite the overall warming. But they aren’t. Cold outbreaks have also moderated slightly just like the winters have moderated slightly. There is no evidence whatsoever of “bigger and stronger” outbreaks.

Recent science has documented a few key changes in the jet stream. The arctic has warmed more than the tropics. This has weakened the north to south temperature gradient which in turn has weakened and slowed the jet stream. The result has been slightly longer lasting weather regimes like cold, warm, rainy or dry. But this has also led to slightly weaker storms, not stronger ones as is often claimed. 

In the highly politicized world of climate change these days, it’s imperative to view everything you read or hear with great skepticism.


January Recap

January was remarkably “normal” by historical standards. The month started warm and finished cold but was overall close to the historical standard. Snow fell on the 12th, totaling almost five inches. We also had a touch of snow on the 17th, 18th and 29th. Rainfall was above normal for the tenth month in a row, but not by much.


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