There's been a great deal of discussion about the Pacific Ocean trends during the year 2014. Back in February, there were forecasts of an El Nino to form that would rival the super El Nino of the late 1990s. Jump ahead to mid-June, and while the is indeed some El Nino-related influence on weather patterns, the actual ocean conditions are not matching up quite as well. The biggest holdout, as many of you know, is the barometric feature known as the Southern Oscillation Index (SOI); this feature has stalled out in a neutral category.
What is going on to keep the SOI from joining ranks, so to speak, toward the El Nino objective? There's not a definitive answer at this time, other than to say that the circulation pattern in the tropical Pacific has not gone into a prevailing west-to-east tendency. Certainly the water temperature is at El Nino levels; data kept for the eastern Pacific by my colleague Mike Palmerino show that the eastern Pacific region has a temperature trend of +1.5 deg Celsius above normal. That temperature level is in a moderate category for El Nino on temperatures.
There is some question as to whether this event will become a hybrid type of El Nino--an entity known as "El Nino Modoki". (pronounced MOE-doe-kye) This type of El Nino definition is fairly new; first recorded in 1986. The name "Modoki" is Japanese for "similar, but different".
In an El Nino Modoki, the Pacific water temperature pattern features a large pool of warm water in the central part of the ocean, with cooler conditions on both sides--South America on the east, and the Asian archipelago on the west. An El Nino Modoki is associated with some different trends than a typical El Nino--the most dramatic one being that, in an El Nino Modoki, hurricane threats to the U.S. mainland are greater than in a typical eastern Pacific-focused El Nino. As of this blog posting on Friday, June 20, 2014, I was not able to identify any definite impact references to agriculture in the U.S., South America, Australia, or Asia.
Is it possible that an El Nino Modoki is in the very early stages of forming? Yes, very tentatively. The Pacific temperatures right now are warm across the entire equator region, with the warmest values relative to normal just off the South America coast near Ecuador-Peru. So, right now, those water temperatures are not in an El Nino Modoki category. However, not too far to the south, there is a good-sized area of the ocean where the water temperature is running around one-half degree Celsius below normal. This pool is not too far from the island of Tahiti, where one of the barometers for computing the SOI is stationed--so, perhaps this is why the SOI has been hovering near neutral. And, if the cooler-temperature pool expands northward, there could indeed be an El Nino Modoki forming--possibly.
I'm going to do more looking into the El Nino Modoki topic, particularly regarding its potential agricultural effects. I am especially curious as to the relationship to precipitation in the western and southern U.S., drought in Australia, and the performance of the India monsoon. We have seen indications of a traditional El Nino-related effect in some of these areas already; whether a developing El Nino Modoki would change that or not is definitely worth more study.
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