Jet Stream So Weak Winds Are Running From Pacific to Atlantic Across the North Pole

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(Winds flowing north from just west of Hawaii, through the Bering Strait, over the North Pole and on into the North Atlantic as seen by¬†NOAA’s GFS model and imaged by Earth Nullschool.)

This is a very odd pattern for global surface winds.

In the central Pacific, along a band above 20 North Latitude and about 500 miles west of Hawaii, a broad stream of easterly winds yesterday took a turn toward the north. The wind field was then pulled into a long frontal boundary spinning out from a large low pressure system off Irkutsk, Russian and driven on toward the Western Aleutian Island Chain.

The winds continued their sprint northward through the Bering Strait before being again captured by a low, this time over the East Siberian Sea. Sped on by this second nudge, the winds, running at 15-25 mph, spilled over the North Pole and into a third low spinning just north of Svalbard. This system shoved the winds southward over the North Atlantic and finally into a cyclone just north of England where the winds finally turned eastward, returning to the prevailing west-east global flow.

This is an epic journey in defiance of typical and prevailing weather patterns spanning thousands of miles and three oceans. It is decidedly not normal.

A Ruptured Jet Stream and A Flood of Winds Across the Pole

Typically, cold air over the polar region will insulate the Arctic from these kinds of circumpolar flows. The cold air to the north, warm air to the south, drives winds faster around the pole, creating a kind of wind wall that keeps south-north flows out of the Arctic. It is a pattern that tends to isolate Arctic air from the rest of the global air circulation to the south.

Jet Stream 30 July 2014

(Mostly disassociated Jet Stream with large rupture running north through the Bering Strait and on over the polar zone. Image source: University of Maine.)

But, during recent years, temperatures in the far north have been rapidly rising by in some cases as much as 0.5 to 1.0 degrees Celsius per decade. This heating of the polar zone, together with land and sea ice loss, has resulted in a weakening of the circumpolar wind pattern called the Jet Stream. This weakening has collapsed the wall keeping southerly winds from rushing over the Arctic as we see today.

The current pattern involves an extreme weakness and high amplitude wave in the Jet Stream extending from the Central Pacific and into the Arctic, extending well above the 80 degree North Latitude line. What remains of the cold air pool has been split, with some of the cold air mass shoved toward Greenland and the Canadian Archipelago and the remainder shoved toward the Kara Sea. Driving through it all is a wedge of warmer air accompanied with the southerly winds, winds that originated in the tropics near Hawaii.

Links:

Earth Nullschool

NOAA/GFS

University of Maine

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