How 'the blob' caused USA's weird weather

A strange, persistent "blob" of very warm water off the U.S. West Coast is now linked to the recent winters that brought extreme heat and drought to the West, and record snow and cold to much of the East, according to two studies.

"In the fall of 2013 and early 2014, we started to notice a big, almost circular mass of water that just didn't cool off as much as it usually did. So by spring of 2014, it was warmer than we had ever seen it for that time of year," said Nick Bond, a University of Washington climate scientist and lead author of one of the studies.

At one point, the blob of ocean water was 2 to 7 degrees above average and about 1,000 miles across and 300 feet deep. Since then, though, "the pattern has evolved to be more like a wide strip along the coast," Bond said.

The two studies were published in the journal Geophysical Research Letters, a publication of the American Geophysical Union.

The blob may have had some influence on the severe drought in the West, Bond said. As air passes over warmer water and reaches the coast, it produces more rain and less snow in the mountains. The low snowpack results in reduced summer water supplies for California, Oregon and Washington.

Bond said this strip of warm water is expected to remain through the end of the year.

The blob is caused by a persistent high-pressure ridge that set up off the West Coast during the winter of 2013-14. It then reformed inland over western North America this past winter, he said.

A high-pressure ridge features sinking air, which prevents clouds from forming and precipitation from falling.

In a surprise, the blob is also related to weather in the central and eastern U.S., which have endured a pair of frigid, snowy winters, according to a separate study by Dennis Hartmann, an atmospheric scientist also at the University of Washington.

Despite all the headlines about the "polar vortex," Hartmann said scientists should look to the Pacific Ocean to understand why so much cold air barreled into cities like Chicago and Boston.

The decade-long climate pattern Hartmann studied is called the North Pacific Mode, which involves changes in water temperatures in the region of the warm "blob," and in the far western Pacific near Asia.

His study indicates that the western Pacific is linked to the cold and snow that blasted into the central and eastern U.S. states.

The warm blob is also harming West Coast marine life. Pacific Coast salmon and steelhead trout, for instance, will decline in numbers if the warm water continues, because both species need prey associated with cold water to survive, according to weather.com.

Meanwhile, surveys from the National Oceanic and Atmospheric Administration found that sea nettle jellyfish, ocean sunfish and handful of different shark species have popped up off the West Coast — where they usually aren't seen — drawn by the warmer ocean temperatures.

Over the past three months, hundreds of emaciated sea lion pups have washed up on the Southern California coast, and the new study could explain why the marine mammals are starving.

Bond said that although the "blob" does not seem to be caused by climate change, it has many of the same effects for West Coast weather.

"This is a taste of what the ocean will be like in future decades," Bond said. "It wasn't caused by global warming, but it's producing conditions that we think are going to be more common with global warming."