The southern U.S. is expected to experience the most significant impacts from El Niño this winter. States along the Gulf Coast and in the Southeast may see heavy rainfall, flooding, and even severe weather events like tornadoes. The West Coast, particularly California, could face atmospheric rivers that bring heavy rain, landslides, and mountain road closures. Meanwhile, the northern U.S., including the Northeast and Midwest, is likely to experience milder winters with below-average snowfall, though isolated storms could still occur.