GENEVA, Aug 31 (Reuters) – The La Nina weather pattern will last until at least the end of the year, becoming the first time this century it will have spanned three consecutive northern winters, the World Meteorological Organization predicted on Wednesday.

La Nina conditions in the tropical Pacific strengthened as trade winds intensified in mid-July to mid-August, affecting temperatures and precipitation patterns and exacerbating drought and flooding in different parts of the world.

The WMO’s El Nino/La Nina Update foresaw the current La Nina – which started in September 2020 – continuing over the next six months, with a 70% chance in September-November 2022 and decreasing to 55% in December-February 2022-2023.

La Nina refers to the cooling of ocean surface temperatures coupled with winds and rainfall. It usually has the opposite impact on weather and climate as El Nino, which is the warm phase of the so-called El Nino Southern Oscillation (ENSO).”It is exceptional to have three consecutive years with a La Nina event. Its cooling influence is temporarily slowing the rise in global temperatures – but it will not halt or reverse the long-term warming trend,” WMO Secretary-General Petteri Taalas said in a statement.

He said the worsening drought in the Horn of Africa and southern South America bore the hallmarks of La Nina, as did above-average rainfall in southeast Asia and Australasia.

“The new La Nina Update unfortunately confirms regional climate projections that the devastating drought in the Horn of Africa will worsen and affect millions of people,” he added.

(Reporting by Michael Shields; Editing by Mark Heinrich)