A stalled atmospheric set-up has made Boston and surrounding areas in the Northeast the most popular truck stop for storms travelling the atmospheric highway known as the jet stream. And stop they have, like a caravan of tractor-trailers idling in a rest stop parking lot.

The Arctic Oscillation describes simultaneous, geographically “choreographed” shifts in multiple features of the polar vortex: air pressure, temperature, and the location and strength of the jet stream. They all follow the hemisphere-wide oscillation of atmospheric mass back and forth between the Arctic and the middle latitudes, sort of like water sloshing in a bowl.

Meteorologists have known for years that the pattern of the polar vortex determines how much cold air escapes from the Arctic and makes its way to the U.S. during the winter. Climate scientists are wondering if a warmer Arctic could explain its odd behavior in recent years.

For those who are still waiting for winter's first snow, Deke Arndt blogs about using historical climate data to ballpark when it might arrive.