Published: January 2016
Extreme Weather: The Arctic Connection
The polar jet stream is a high-altitude air current that separates low-pressure Arctic air—aka the polar vortex—from warmer, high-pressure air to the south. When the jet dips far south, it can deliver blasts of cold and snow to temperate latitudes; a north-jutting ridge promotes heat and drought. Such extreme weather has been happening a lot lately. Scientists are debating whether that’s primarily due to the shifting cycles of the Pacific—or whether the melting Arctic plays a key role.
Graphics by Lauren James, Jason Treat, and Daniela Santamarina
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STRAIGHTER JET STREAM

The jet stream gets most of its energy from the temperature contrast between the air masses it separates. A strong jet is a straighter jet that keeps cold air bottled up in the Arctic.

Temperature

30˚

Mid-latitudes

90˚

Pole

Latitude

WAVIER JET STREAM

As the Arctic warms faster than the midlatitudes, the temperature contrast decreases. That weakens the jet, letting Arctic air flow south—over eastern North America, for instance.

30˚

Mid-latitudes

90˚

Pole

Latitude

SOURCES: JENNIFER FRANCIS, RUTGERS UNIVERSITY; DENNIS HARTMANN,UNIVERSITY OF WASHINGTON

STRAIGHTER JET STREAM

The jet stream gets most of its energy from the temperature contrast between the air masses it separates. A strong jet is a straighter jet that keeps cold air bottled up in the Arctic.

Temperature

30˚

Mid-latitudes

90˚

Pole

Latitude

WAVIER JET STREAM

As the Arctic warms faster than the midlatitudes, the temperature contrast decreases. That weakens the jet, letting Arctic air flow south—over eastern North America, for instance.

30˚

Mid-latitudes

90˚

Pole

Latitude

SOURCES: JENNIFER FRANCIS, RUTGERS UNIVERSITY; DENNIS HARTMANN,UNIVERSITY OF WASHINGTON

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