2012-Will there be an El Nino?
By Richard Sparago on July 13, 2012, 8:35am
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This week, Australian Bureau of Meteorology published its outlook on whether or not there will be an El Nino in 2012. You may ask why we should pay attention to the Australian Weather Bureau. El Nino patterns develop in the equatorial Pacific, and have a profound impact on Australian weather. It's amazing how a phenomenon, characterized by an increase in surface water temperatures in the Pacific, can have a strong influence in Australian weather as well as our CT weather. The Australian Bureau published that an El Nino is beginning to develop (rising water temps in the Pacific), though models show significant differences on where the pattern will go from here. Some models suggest continued development toward a normal El Nino, while others show that this year's El Nino will be weaker than average, and others show such variability that there may be no El Nino this year.
Let's assume there is an El Nino this year. We're already seeing some typical signs, with an active cyclone season in the Pacific, and a quiet cyclone season in the Atlantic. What else can we expect? That depends on the strength of the El Nino. Usually El Nino winters are mild in the northeast, with precipitation about average. Other areas of the country, such as the southwest and southeast, could see a wet pattern. Both of these drought-stricken areas would benefit from the rainfall. But, if the El Nino develops and is weaker than average, there are indications that this could lead to a cold and snowy winter in the northeast. Matt Rogers, a forecaster at the Commodity Weather Group says, “Weak El Ninos are notorious for cold and snowy weather on the Eastern seaboard. About 70 percent to 75 percent of the time a weak El Nino will deliver the goods in terms of above-normal heating demand and cold weather. It’s pretty good odds.” This will definitely bear watching.
La Nina is the opposite of El Nino. This cooling of Pacific waters is supposed to produce cold and snowy winters in the US, especially the northeast. We are just emerging from a La Nina that officially dissipated in April of 2012. But last winter was so mild, how could we have been in a La Nina? Well, according to Pacific water temperatures, La Nina definitely was in place. Its impact on us was an anomaly. But its impact on other parts of the US were quite typical, especially the drought conditions it produced in the southwest.
La Nina and El Nino do not necessarily follow each other. There could be years of average water temperatures in the Pacific, producing neither pattern. In fact, El Ninos are usually spaced by 3-7 years. When they do develop, El Nino patterns last from a few months to as much as a year. The bottom line is that there are some preliminary signs of El Nino this year, but there is not agreement on its certainty or strength. Both of these are critical points for our weather. We'll just have to wait, watch, and continue to dip our thermometers in the waters of the equatorial Pacific.
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