La Niña conditions could develop in the fall and early winter, but they will probably be weak and short-lived, forecasters say.
La Niña is the cold phase of the El Niño-Southern Oscillation (ENSO), a natural climate pattern of atmospheric and sea temperature changes in the tropical Pacific Ocean. During La Niña, the jet stream shifts northward, bringing wetter conditions and cooler winters to the northern U.S., while the southern U.S. experiences drier conditions and warmer winters. A La Niña also tends to ramp up hurricane activity over the Atlantic.
