A Melting Arctic and Weird Weather: the Plot Thickens

Everyone loves to talk about the weather, and this winter Mother Nature has served up a feast to chew on.  Few parts of the US have been spared her wrath.

Severe drought and abnormally warm conditions continue in the west, with the first-ever rain-free January in San Francisco; bitter cold hangs tough over the upper Midwest and Northeast; and New England is being buried by a seemingly endless string of snowy nor’easters.

Yes, droughts, cold and snowstorms have happened before, but the persistence of this pattern over North America is starting to raise eyebrows.  Is climate change at work here?

Wavier jet stream



One thing we do know is that the polar jet stream – a fast river of wind up where jets fly that circumnavigates the northern hemisphere – has been doing some odd things in recent years.

Rather than circling in a relatively straight path, the jet stream has meandered more in north-south waves.  In the west, it’s been bulging northward, arguably since December 2013 – a pattern dubbed the “Ridiculously Resilient Ridge” by meteorologists.  In the east, we’ve seen its southern-dipping counterpart, which I call the “Terribly Tenacious Trough.” 

These long-lived shifts from the polar jet stream’s typical pattern have been responsible for some wicked weather this winter, with cold Arctic winds blasting everywhere from the Windy City to the Big Apple for weeks at a time.

We know that climate change is increasing the odds of extreme weather such as heatwaves, droughts and unusually heavy precipitation events, but is it making these sticky jet-stream patterns more likely, too?  Maybe.
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Our own new work, published last month in Environmental Research Letters, uses a variety of new metrics to show that the jet stream is becoming wavier and that rapid Arctic warming is playing a role.  If these results are confirmed, then we’ll see our weather patterns become more persistent.

In other words, Ridiculously Resilient Ridges and Terribly Tenacious Troughs may become the norm, along with the weather woes they cause.

Read more at A Melting Arctic and Weird Weather:  the Plot Thickens