The winter of 2011-2012 will be governed by the re-emergence of La Niña that happened this summer. Unfortunately, the Southwest and Southern Plains aren't likely to see any relief from the extreme drought conditions they have experienced this year, with warmer and drier than normal conditions expected. Other areas of the country will see the opposite.
Here are the highlights of the winter weather outlook, from December through February, for different regions of the United States:
- Pacific Northwest: colder and wetter than average. La Niña often results in below-average temperatures and increased mountain snow in the Pacific Northwest and western Montana during the winter months. This may set the stage for spring flooding in the Missouri River Basin;
- California: colder than average with odds favoring wetter than average conditions in northern California and drier than average conditions in southern California. All of the southern part of the nation are at risk of having above normal wildfire conditions starting this winter and lasting into the spring;
- Northern Plains: colder and wetter than average. Spring flooding could be a concern in parts of this region;
- Southern Plains and Gulf Coast States: warmer and drier than average. This will likely exacerbate drought conditions in these regions;
- Florida and south Atlantic Coast: drier than average, with an equal chance for above-, near-, or below-normal temperatures. Above normal wildfire conditions;
- Ohio and Tennessee Valleys: wetter than average with equal chances for above-, near-, or below-average temperatures. Potential for increased storminess and flooding;
- Northeast and Mid-Atlantic: equal chances for above-, near-, or below-normal temperatures and precipitation. Winter weather for these regions is often driven not by La Niña but by the Arctic Oscillation. If enough cold air and moisture are in place, areas north of the Ohio Valley and into the Northeast could see above-average snow;
- Great Lakes: tilt toward colder and wetter than average;
- Hawaii: Above-average temperatures are favored in the western islands with equal chances of above-, near-, or below average average precipitation. Statewide, the current drought is expected to continue through the winter. Drought recovery is more likely over the windward slopes of the Big Island and Maui;
- Alaska: colder than average over the southern half of the state and the panhandle with below average precipitation in the interior eastern part of the state.