California Believed in Path as Cold Wave Marches East to West : Bizarre Weather Tied to ‘Blocked’ Atmospheric Flow

It may offer little consolation to those caught in its freezing grip, but the cold wave that has paralyzed the East Coast has given scientists a dandy glimpse into global weather patterns.

“It’s a thrilling thing to watch,” said Jerome Namias, one of the most respected meteorologists in the country. He conceded, however, that it’s more comfortable to watch from his office at La Jolla’s Scripps Institution of Oceanography than from the Eastern Seaboard, where scores of records have been toppled by the frigid temperatures.

Namias said the bizarre weather is slowly marching westward around the world toward the region where it all began, the northern reaches of Siberia. He thinks it will pass across the Pacific Coast in the near future, probably bringing rain--not snow--to Southern California.

“I’m not predicting a catastrophe (for California),” he said, “but it probably will break this dry spell.”

Namias said he believes the storm began to pick up speed over Northern Europe several weeks ago before it began its assault on the Atlantic states. He said he thinks it will move slowly across the country and over the Pacific, and possibly end up in the Far East, not far from its point of origin.

“The instigator of this cold air outbreak has something to do with events which took place in Europe,” Namias said. He said high atmospheric pressures in the Northern European countries and Siberia pushed cold weather south, “encouraging storms to form in the Mediterranean and Southern Europe.”

That resulted in something called “blocking,” Namias said. The term, he added, means the normal atmospheric flow from west to east is “blocked, for reasons not yet fully understood,” and the westerly winds that normally would confine the cold to Europe do not form.

“When that happens, the cold moves westward very slowly,” he said. It reached the Atlantic coast a couple of weeks ago, creating high-pressure areas over the Arctic and thus forcing cold weather south.

Additional storms form along the forward ridge of the cold front, and “each storm drags more cold air down with it as it moves south.” Thus the weather system--while really moving east to west--has been dubbed the “Alberta Clipper” because of the blasts of cold air it has delivered in more temperate parts of Europe and North America.

Roger Wakimoto of UCLA’s atmospheric sciences department described the phenomenon as “a chain reaction type of thing.”

Like Namias, Wakimoto said he cannot explain the “blocking” effect, but he said it has a profound effect on weather patterns, both when it forms and when it fails.

“I would be more interested in what causes it to break down,” thus allowing storms to move into unexpected areas, Wakimoto said. “If we could do that, the accuracy of our predictions would go much higher.”

Fred Ostby, director of the National Severe Storm Center in Kansas City, Mo., also agreed that the cold front is probably global in scope, but added that the freezing temperatures of the last few days are a bit frightening.

“One of the things we are seeing is more and more variability as time goes on,” Ostby said. “The longer we keep records, you would think it would get harder and harder to break them, but one of the things that seems a little odd is we seem to be breaking more records. There are wider swings between heat and cold.”

“I’m not sure what it all means,” Ostby said. “It’s wild.”