Droughts in West and Arctic Winters in the East: A 4000-Year Weather Pattern Explained

This past winter, the West (particularly California) experienced droughts and the East faced extreme and fluctuating winter weather. Researchers from across the world found interesting information about the jet stream pattern that causes this.

Led by University of Utah geochemist Gabe Bowen, researchers from Tianjin Normal University in China, University of Tokyo, University of Southern California, French National Center for Scientific Research, University of Alaska at Anchorage, and Cleveland State University had their study published in the journal Nature Communications.

They found that the Pacific North American teleconnection, which is the current jet stream pattern, brings North American wintertime extremes and is over 4,000 years old. But there are characteristics of the jet stream that could exacerbate unfavorable weather conditions.

"A sinuous or curvy winter jet stream means unusual warmth in the West, drought conditions in part of the West, and abnormally cold winters in the East and Southeast," said Bowen, in a news release. "We saw a good example of extreme wintertime climate that largely fit that pattern this past winter."

The researchers' study also found that global warming is likely to enhance the jet stream pattern, which will contribute to harsher winters in the East and longer droughts in the West. The warmer climate is expected to make the jet stream more frequent and possibly more intense as time progresses.

The sinuous jet stream causes the winter weather extremes because the wind is very winding, which has the ability to send weather in different directions. Bowen describes that the stream comes from Hawaii and the Pacific, then rockets up past British Columbia to the Yukon and Alaska, and then makes it way down to the eastern U.S. This is where the harsh winters come from because the arctic air is sent downward.

Although the pattern has existed for 4,000 years, the extremities of the winter season have worsened as the climate has gotten warmer (a likely cause of global warming).