Early May Weather Pattern Will Be Especially Extreme in Northern Hemisphere

During the course of the next 10 days or more, the weather pattern across the Northern Hemisphere will feature an undulating, wavy jet stream that will be stuck in place, with storms backed up like cars on an interstate highway at rush hour. 

Large dips in the jet stream, which is the narrow current of fast-flowing air at high altitudes that plays a crucial role in creating and steering weather systems, will lead to prolonged periods of cool, wet weather across the West and East Coasts of the U.S.  Snow is even possible in parts of the Northeast U.S. during the second week of May. (Seriously.)

At the same time, unseasonably mild weather is projected to envelop Greenland and parts of Canada, potentially initiating an early start to the ice melt season there and melting remaining snow cover in Alberta and Nunavut.

And this is just part of the story.  Extremes will also occur further east, across Europe, Russia, and eastern Asia. 

The particular weather pattern that's shaping up is known as a wavenumber 6 pattern, named for the six large north-south dips in the jet stream, arrayed around the hemisphere.
Recent studies have tied historic extreme events to this weather pattern, particularly during the summer months. 

A recent study, published in the journal Nature Scientific Reports, proposes a link between more frequent high-amplitude, stuck weather patterns (and their associated extreme events) during the summer, with Arctic climate change.  The hypothesis there is that Arctic warming has been increasing the odds in favor of slower-moving, undulating jet stream patterns.

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