Saturday, June 6, 2009

El Nino Looks to be Forming in the Pacific

El Nino, also known as the 'Southern Oscillation' is a weather pattern associated with abnormally high ocean temperatures in the Pacific ocean, near and North of the equator. On the graphic above, we've highlighted a region in the Pacific ocean where ocean temperatures are running 10-15 degrees above normal for this time of the year. The occurrence of this pattern, and the fact that it is spreading westward all along the region North of the equator, is typical of the early stages of El Nino development. What impact does El Nino have on the weather, particularly in the United States? Initially, the impact for the summer would be lower than normal amounts of tropical weather activity in the Carribean, Gulf of Mexico and western Atlantic. This doesn't mean that there won't be any tropical development, just that there is likely to be less development than normal. This of course, is a relative statement, because if a tropical storm or hurricane impacts your area, you certainly won't feel like the season has been less active than normal. If an El Nino pattern is indeed forming, and continues to mature through the summer months, the next impact would be to the southern and central United States during the Fall and Winter. In a mature El Nino pattern, cooler and wetter than normal weather conditions can be expected along the southern tier of the U.S. from October through March.

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