Odds are it's going to be a colder, wetter winter than normal, courtesy of the La Nina effect.

The National Oceanic and Atmospheric Administration, which monitors ocean temperatures worldwide, issued a La Nina advisory Sept. 9. The cool sea temperatures of La Nina - Spanish for "little girl" - create colder winters from the Pacific Northwest to the Great Lakes region. La Nina is the opposite of El Nino, which warms the tropical Pacific Ocean, causing unusually warm Northwest winters.

Sea temperatures have been dropping and entered La Nina territory by the end of August, NOAA reported, indicating that La Nina will be moderate at least. The NOAA predicted La Nina will last through early 2011.

Although "it's hard to draw concrete conclusions" about the winter this far in advance, there's a "possibility of snow and ice" and "potentially more flooding," Weather Service meteorologist Jeremiah Pyle said Sunday.

However, weather expert Cliff Mass, professor of atmospheric sciences at the University of Washington, wrote on his blog that mega-floods are more common during years that are neither La Nina nor El Nino.

"So although we expect this fall and winter to be wetter than normal (due to La Nina), there is less chance for a mega-rain/flooding event," he wrote. "Yes, it could happen, but it is less likely."

The Oregon Climate Service also predicts a La Nina effect bringing a greater chance of a wetter-than-average fall and winter. Expect below average temperatures, too, according to the Climate Service, part of the College of Oceanic and Atmospheric Sciences at Oregon State University.

Cowlitz County has a stretch of La Ninas to thank for some of its soggiest years. From 1995 to 1999, three of the four winters were La Ninas (the other was a super-El Nino) drenching the area with more than 55 inches of rain each year - the wettest five-year period in Longview history.

Southwest Washington suffered widespread flooding in November 1995 and even worse flooding less than three months later in February 1996. The second "100-year flood" of the winter was the worst natural disaster to strike Cowlitz County since the 1980 eruption of Mount St. Helens.

The 1998-'99 La Nina was one of the century's strongest, producing a stream of violent storms. The winter of 1998-99 also experienced record snowfall in the mountains due to an "arctic express" weather pattern - a stream of cold, moist air from Alaska that sometimes accompanies La Nina.

Another arctic express during a La Nina in 2007-08 produced a frigid March and April. A series of squalls and hailstorms April 19, 2008, caused eight one-car accidents in two hours throughout the county.

But there's no certainty La Nina will produce an arctic winter or record rain to a region that barely dried out from an unusually squishy spring.

However, the Weather Service is fairly sure of one thing: It’ll be partly sunny today with temperatures in the 70s and clouds moving in tonight.

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