Chances of a Weather-Roiling La Niña This Year Are Now Above 80%

The odds of a weather-roiling La Niña in the coming months are rising, elevating the risk of an unusually active Atlantic hurricane season.

The chances of La Niña, a cooling of the equatorial Pacific, rose to 82% for August, September and October, the US Climate Prediction Center said. Last month there was a 74% chance.

“The numbers edged upwards, not dramatically, and the timing still seems to be the same as to what we were predicting last month,” said Michelle L’Heureux, a forecaster with the center.

La Niña can lead to droughts in South America and California and more rain across parts of Indonesia and Australia. Currently a strong El Niño, or warming in the Pacific, is winding down. La Niñas often follow intense El Niños because of a phenomenon known as discharge, when heat on the equator migrates toward the poles and cold deep-ocean waters rise to take its place.