Climate troublemaker El Niño is forecast for this coming fall and winter, the Climate Prediction Center announced Thursday. The agency said there’s a 65 percent chance it will form by the winter, prompting it to issue an El Niño watch. In the U.S., a strong El Niño can result in a stormy winter along the West Coast, a wet winter across the South and a warmer-than-average winter in the Pacific Northwest and northern Rocky Mountains.