West Coast Winter will have Conflicting Weather Patterns

October 26, 2010; 1:03 PM ET
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In his 2010-2011 Winter Forecast, AccuWeather.com Expert Long-Range Forecaster Joe Bastardi predicts above-normal snow and cold for the Pacific Northwest, and a non-winter for Southern California into the Desert Southwest.

What makes the outcome of this winter crucial is the area between the two regions, what AccuWeather.com Expert Senior Meteorologist and West Coast Expert Ken Clark refers to as a "no man's land" of two opposing weather patterns.

The relatively strong La Niña will have an effect on much of the upcoming winter's conditions, which Clark said has a correlation with a drier than normal winter season.

During a La Niña winter, the southern jet stream (a band of strong winds high up in the atmosphere) moves northward, channeling more storms and cold snaps into the northern half of the country. This means the Pacific Northwest in for a stormy, wetter-than-normal winter, while the southern half of the country is in for a dry season.

Bastardi indicates areas of the interior Northwest as getting some of the worst of of the nation's snow and cold this winter. Areas such as Spokane, Wash., with receive above-normal snow and ice.

The good news is that the building of the snowpack across the Pacific Northwest is essential to hydroelectric production in the spring and summer.

Additionally, areas of northern California, such as the San Francisco Bay Area, are in for a wet season as well.

With this La Niña pattern, Southern California and the desert areas of the Southwest are in for a dry winter.

Although a stronger La Niña is in place, Clark said, that doesn't mean a few storms won't make their way into California and the Sierras.

The area between these two very different weather patterns will be a "battlezone" of sorts, according to Clark. He adds that what winter will bring to the central Sierra Nevada region in particular is crucial, since it will determine the future of water supply conditions for much of the region.

"The L.A. metro area gets about 80 percent of its water from the drainage from the central Sierras," he said.

Areas of coastal Southern California will see rainfall this winter, but less than normal. Areas east of the mountains across southeastern California and into Arizona will have the driest conditions of the winter.

Nevada's Lake Mead is reaching critically low levels, and the dry winter ahead will not aid the situation.

Be sure to check out Joe Bastardi's complete 2010-11 Winter Forecast and check back with AccuWeather.com through the coming weeks as we continue to forecast the upcoming winter conditions.


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