UN agency predicts phenomenon that supercharges weather extremes has 80% chance of forming before September UN agency predicts phenomenon that supercharges weather extremes has 80% chance of forming before September The world must prepare for the imminent return of El Niño and the supercharged weather extremes it brings, the UN has warned. The powerful natural weather pattern, which raises global temperatures and worsens some rainfall, has an 80% chance of forming before September and a 90%