The El Nino-Southern Oscillation, or ENSO, is the single most important predictor of seasonal climate in the Southeast, so we tend to watch it fairly closely to see if it can give us clues to future conditions. But researchers have found that a shift in ENSO patterns has reduced our ability to make useful predictions. This shift happened around 1999-2000 and reduced the accuracy of model predictions after that point. You can read more about it and find a link to the original research paper here.
