Scientists have recently discovered a positive relationship between an alternative type of El Nino, called El Nino Modoki, and Atlantic hurricane activity. The connection had largely slipped under the radar because the scientists in Japan and Korea who knew the most about Modoki did not connect it with Atlantic hurricanes. (It would just figure. This has happened before with respect to ENSO and hurricanes; the ENSO specialists didn’t work with the hurricane specialists, and so that connection wasn’t known for years either.) This type of El Nino involves warming in the central and/or western Pacific rather than the Pacific coast of South America, and it is associated with increased Atlantic hurricane activity and increased landfalls—unlike the traditional El Nino, which tends to suppress activity in this basin.
2004 (of Ivan infamy) was an El Nino Modoki year. 2006 was a traditional El Nino year. 2009… may be a split:
“We spent all last week trying to figure that out,” [Peter] Webster [meteorologist of Georgia Tech] said. ‘It looks like it might be a hybrid,” with warming starting in the east and them moving west, possibly meaning more hurricanes late in the season.
Webster speculates that the Modoki phenomenon may be caused by global warming. Then again, it may not be. I’m rather interested, in fact, in the year 1969, which was an El Nino year for most months but still had a highly active hurricane season, including record Hurricane Camille. General consensus is that we are just now seeing the effects of climate change in our weather, so 1969 may (or may not) be out of the window of opportunity for global warming to have had an effect on El Nino.
As far as that “increased late-season hurricane activity” is concerned, though… that’s about what I figured. I’ve been seeing parallels between the oceanic setup of this year and 2004, and that rather reinforces my belief.