The National Oceanic and Atmospheric Administration (NOAA) says La Nina is expected to peak this winter and models are split between those that expect it to remain weak and those that predict a stronger episode.
"Over the last half-century, La Nina events that were preceded by ENSO-neutral conditions during the Northern Hemisphere summer (May-August) were less likely to attain strong amplitude the following winter," reminds NOAA. "This observation, in combination with the model forecasts, favors a weak-to-moderate strength La Nina during the Northern Hemisphere winter, likely weakening with the onset of northern spring."
During December through February 2012, NOAA says there is an increased chance of above-average temperatures across the south-central and southeastern U.S. below-average temperatures over the western and north-central U.S. Also, above-average precipitation is favored across the northern tier of states, excluding New England, and drier-than-average conditions are more likely across the southern tier of the U.S.
Juli says: Even though La Nina is weaker than the previous episode, it can still have a big impact on the weather. The forecast for the Plains this winter signals the winter wheat crop will come out of dormancy in tough shape. The outlook also isn't promising for drought relief in the western Corn Belt this winter, meaning soil moisture will need to be recharged this spring.