Weak La Niña conditions may develop soon: WMO
Photo: World Meteorological Organization
WMO — La Niña conditions may develop in the next three months but are expected to be relatively weak and short-lived, according to the latest update from the World Meteorological Organization.
The WMO long range forecasts indicate a 55 per cent likelihood of a transition from the current neutral conditions to La Niña conditions during December 2024 to February 2025.
The return of the ENSO-neutral conditions is then favored during February to April 2025.
La Niña refers to the large-scale cooling of the ocean surface temperatures in the central and eastern equatorial Pacific Ocean, coupled with changes in the tropical atmospheric circulation, such as winds, pressure and rainfall. Generally, La Niña produces the opposite large-scale climate impacts to El Niño, especially in tropical regions.
However, naturally occurring climate events such as La Niña and El Nino events are taking place in the broader context of human-induced climate change, which is increasing global temperatures, exacerbating extreme weather and climate, and impacting seasonal rainfall and temperature patterns.
“The year 2024 started out with El Niño and is on track to be the hottest on record. Even if a La Niña event does emerge, its short-term cooling impact will be insufficient to counterbalance the warming effect of record heat-trapping greenhouse gases in the atmosphere,” said WMO Secretary-General Celeste Saulo in the news release.
“Even in the absence of El Niño or La Niña conditions since May, we have witnessed an extraordinary series of extreme weather events, including record-breaking rainfall and flooding which have unfortunately become the new norm in our changing climate,” said Celeste Saulo.
As of the end of November 2024, oceanic and atmospheric observations continue to reflect ENSO-neutral conditions which have persisted since May. Sea surface temperatures are slightly below average over much of the central to eastern equatorial Pacific.
However, this cooling has not yet reached typical La Niña thresholds. One possible reason for this slow development is the strong westerly wind anomalies observed for much September to early November 2024, which are not conducive for La Niña development.
