In late February, an invasion of warm, southern air sent temperatures surging above freezing across the Arctic and toward the North Pole. In the two weeks since then, three nor’easters have smacked New England and the surrounding areas.
As the Arctic warms, this trend has become common in recent winters, and it’s drawn new attention to links between the polar vortex — a constant mass of cold, dense air rotating over the north pole — and weather patterns farther south.
When the polar vortex weakens like it has several times this winter, it can cause the jet stream to buckle and smash cold Arctic air into warm and wet air to the south. The result: severe winter storms.
