COLUMBIA — For the second consecutive year, La Niña stands to play a major role in Missouri's winter weather.
A winter forecast released Thursday by the Climate Prediction Center called for wet and cold conditions in the Northern Plains and dry, warmer weather in the South.
Since Missouri is wedged in between, Mike Halpert of the climate center said there was a high probability the state will experience both extremes.
"We expect conditions to be colder and wetter than average extending from the Pacific Northwest to the Great Lakes, while we can expect milder than average temperatures across the South," Halpert said.
It's too early to precisely predict whether the impact from La Nina, a cooling of surface waters in the equatorial Pacific Ocean that affects atmospheric circulation, will be the same as last year, Halpert said, but there will likely be a fair amount of variability in the Midwest.
In the past, Halpert said, La Niña has lead to above average snowfall, which means mid-Missouri could be looking at conditions similar to those during winter 2010.
Snowfall last winter at Columbia Regional Airport totaled 53.4 inches, making the 2010-11 seasonal period the second snowiest on record.
La Niña is weaker than this time last year, Halpert said, but was expected to strengthen in late fall to early winter and affect temperatures and precipitation amounts from December into February.
In general, Halpert said, the below-average temperatures in the Pacific Ocean were expected to contribute to cooler than average temperatures in the U.S.
Precipitation this winter is also likely to exceed the average across the Midwest, which includes Missouri, indicating a possible risk of flooding in spring 2012.
David Brown, regional climate services director for the National Oceanic and Atmospheric Administration, said dry conditions forecast for the South provides a very low chance for relief from the severe drought in Texas, Oklahoma and New Mexico.
Halpert said those areas of drought and areas with too much rain, such as the upper Plains and Missouri River basin, tend to continue those same patterns during the winter.
"We saw a moderate La Niña in 2010 and the redevelopment of it this year," Halpert said. "The shift of the jet stream to the north over the Pacific is partly why we see it dry to the south and wet to the north."
La Niña is expected to continue strengthening, which will effect the outcome of temperatures and precipitation during the winter months from December to February.
Brown said it is not likely the predictions as a result of La Niña will change for the upcoming winter.
"We are confident La Niña is not going anywhere," he said.