As of early November, El Nino has finally begun to strengthen (ENSO Diagnostic Discussion), so the El Nino might become worthy of the attention its received in recent months.
The discussion notes that the El Nino is expected to strengthen to at least moderate levels during the next couple of months and last through the upcoming winter, and the following image show anomalies for the week centered on October 25.
We’ve talked about this before, but one of the main implications of an El Nino during the winter in the United States is the strengthening of the southern storm track, resulting in more frequent storms across the southern tier of the country. This means that an El Nino year is likely to bring increased precipitation amounts to California and the Deep South.
The more active southern storm track could result in a greater number of storms moving northward along the East Coast as well, resulting in a snowier-than-average winter for the Middle Atlantic region (Snowy, Cold Winter on the Way?).
It’s unlikely that the El Nino will become strong enough to be the sole factor in determining the winter weather, but it’s more likely to a significant factor than it might have appeared just last month.
By the way, for more information on El Nino, the Climate PredictionCenter’s El Nino/Southern Oscillation page is great.