U.S. weather forecasters said Thursday the cool flip side to the climate phenomenon El Niño has faded away. The La Niña episode lasted only four months and was among the weakest and shortest on record, coming on the heels of one of the strongest El Niños, said Mike Halpert of the National Oceanic and Atmospheric Administration’s Climate Prediction Center. La Niña, a cooling of parts of the equatorial Pacific that changes weather patterns worldwide, often lasts a year or more, longer than El Niños. La Niña conditions were first detected in October and disappeared in January.