El Niño/La Niña Update (May 2021)

The 2020-2021 La Niña event has concluded, according to both oceanic and atmospheric indicators. The latest forecasts from the WMO Global Producing Centers of Long-Range Forecasts indicate that neutral conditions are likely to dominate the tropical Pacific through the boreal summer: with a 78% chance of neutral for May-July, decreasing to 55% by August-October. ENSO-neutral remains the most likely outcome for the rest of the calendar year. The outlook for the second half of the year, however, contains considerable uncertainty with some suggestions of either a transition to El Niño or a re-emergence of La Niña conditions later this year. National Meteorological and Hydrological Services will closely monitor changes in the state of El Niño/Southern Oscillation (ENSO) over the coming months and provide updated outlooks.