The image above from NASA’s Jason-2 satellite shows that sea level in the equatorial Pacific Ocean is close to normal.
But before you breathe a sigh of relief about the coming winter in the Northern Hemisphere, or summer down under for that matter, read on…
In the image, green tones show sea level that’s about normal, blues and magentas where it is below normal, and reds and yellows the opposite. These colors are also indicative of the temperature of the ocean water. That’s because warmer water expands and thereby leads to higher sea level, whereas the opposite is true of cooler water.
Normal sea level in the equatorial Pacific is characteristic of neutral climatic conditions — neither an El Niño, which raises sea level in the area, nor a La Niña, which lowers it. Instead, it’s called “La Nada.”
It has lasted now for 16 months, and will probably persist at least through the Northern Hemisphere winter, according to the latest update from NOAA’s Climate Prediction Center. (Probabilistic forecasting suggests it could even continue through June.)
El Niño and La Niña can bring their share of disruptive and even destructive weather events. For example, El Niño can bring destructive flooding to the southern tier of the United States, and devastating drought and brushfires to Australia, according to NOAA.
Meanwhile La Niña can bring wetter than normal conditions to Australia — and was, in fact, a significant contributing factor to destructive heavy rainfall in southeastern Australia between October 2011 and March 2012. La Niña was also a significant factor last year in one of the worst droughts on record in the United States.
So La Nada — by definition, the absence of the climatic conditions typically associated with this kind of mayhem — may well sound like good news. But it is actually a bit frustrating to climate forecasters, and it is by no means a reprieve from meteorological nastiness.
Consider these comments from Bill Patzert of NASA’s Jet Propulsion Laboratory, (quoted in a NASA news release):
Without an El Niño or La Niña signal present, other, less predictable, climatic factors will govern fall, winter and spring weather conditions . . . Long-range forecasts are most successful during El Niño and La Niña episodes. The ‘in between’ ocean state, La Nada, is the dominant condition, and is frustrating for long-range forecasters. It’s like driving without a decent road map — it makes forecasting difficult.
In other words, without El Niño or La Niña in the driver’s seat, we’ll be even more in the dark about what may be coming at us this winter and spring.
Also, consider this, again from Patzert:
Neutral infers something benign, but in fact if you look at these La Nada years when neither El Niño nor La Niña are present, they can be the most volatile and punishing. As an example, the continuing, deepening drought in the American West is far from ‘neutral.’
Given all of that, I’m a little at a loss to say what the bottom line here is. But since all of it — El Niño, La Niña and La Nada can be be bad news, I guess the bottom line is simply this: Weather happens.