If El Nino Returns, It Could Be Massive

Wired:

Official NOAA Climate Prediction Center estimates peg the odds of El Niño’s return at 50 percent, but many climate scientists think that is a lowball estimate. And there are several indications that if it materializes, this year’s El Niño could be massive, a lot like the 1997-98 event that was the strongest on record.
“I think there’s no doubt that there’s an El Niño underway,” said climate scientist Kevin Trenberth of the U.S. National Center for Atmospheric Research. “The question is whether it’ll be a small or big one.”
On top of some late-’90s nostalgia, a strong El Niño would bring pronounced changes to weather patterns around the globe, and possibly relief from some of the less-pleasant weather trends that have dominated headlines this year. After a Polar Vortex-fueled, unbearably cold winter in the U.S. Midwest and East Coast, a strong El Niño could bring warmer, drier weather in late 2014. And to parched California and its prolonged drought, El Niño might provide drenching rainstorms to fill up reservoirs. But the news won’t all be good. Rainstorms in California could mean floods and mudslides and, coupled with climate change, El Niño could bring harsher droughts to parts of Australia and Africa....
Should the warm pool make it all the way to the South American coast, a much stronger “full-basin” El Niño will appear. And then we could be in for some big weather changes.
A strong El Niño could start affecting the world as early as the fall. The Pacific hurricane season, which gets active around September, is greatly enhanced during El Niño. This likely means more tropical thunderstorms that could affect eastern Pacific areas such as Mexico. In contrast, Atlantic hurricanes are suppressed, meaning fewer and less severe storms with a lower chance of making landfall and doing damage.
The winter is when El Niño really gets going, though. Moisture flows from Hawaii to southern California in an atmospheric river colloquially known as the “Pineapple Express.” This creates heavy rainfall that dumps on the region. Though this could bring some relief from California’s drought, it also comes with the risk of flash floods and mudslides because the ground has been so hard and dry.
El Niño has other effects further into North America. It tends to enhance the jet stream, creating a wall that prevents Arctic air (and the Polar Vortex) from dipping down to mid-latitudes. East Coast winters are generally drier and warmer during El Niño years, which is probably good news to those still smarting from this recent frigid season. The mild winter has interesting downstream effects, like a boost for the U.S. economy during the Christmas season.

El Nino usually leads to cooler and wetter weather to the growing season, and warmer, drier weather in the winter to our area.