‘La Niña watch’ reinstated

US forecasters yesterday reinstated official ‘watch’ status for La Niña under the ENSO alert system; it was suspended last month after the forecast probability of La Niña – relative cooling of the Pacific – fell to 40 per cent in August.

The diagnostic synopsis issued by the US Climate Prediction Center and the IFRC’s forecasting partners at the International Research Institute for Climate and Society (IRI) gives an approximately 70 per cent chance of La Niña in the northern autumn, with about a 55 per cent chance of it persisting through the winter.

The current position of the Pacific Ocean and atmosphere “remains ENSO-neutral”, says IRI.

El Niño and La Niña are defined slightly differently by national forecasting agencies, “but IRI seasonal forecasts provide a more useful basis for humanitarian decision-making than a single global indicator,” according to Climate Centre Director Maarten van Aalst, speaking last month.

The Climate Centre is planning research on the various definitions of El Niño and (image above) La Niña  in terms of their humanitarian impacts.