The US weather agency, Climate Prediction Centre (CPC), has now joined other agencies in predicting that the emergence of La Nina has been delayed.
In its El Nino-Southern Oscillation (ENSO) discussion on Thursday, it said, “ENSO-neutral is expected to continue for the next several months, with La Niña favoured to emerge during August-October (70% chance) and persist into the Northern Hemisphere winter 2024-25 (79 per cent chance during November-January).”
Initially, La Nina was predicted to emerge in July with CPC giving a 69 per cent chance for the weather event, which brings more rains and floods to Asia particularly India. However, last month it reduced the chance to 65 per cent.
The CPC has also reduced the chance of La Nina persisting during the northern hemisphere winter from 85 per cent last month.
Delayed development
However, the weather agency, an arm of US National Oceanic and Atmospheric Administration, said its forecast team is also favouring a delayed development of La Niña this month, “but is anticipating the transition to occur earlier (August-October)”. This is, in part, has been supported by the continuation of below-average subsurface ocean temperatures and nearterm forecasts suggesting a resurgence of easterly wind anomalies in July, the CPC said.
The most recent plume of the Colombia Climate School’s International Research Institute for Climate and Society (IRI) showed a delay in the emergence of La Nina to September-November 2024, with La Nina then persisting through the Northern Hemisphere winter, the CPC said.
On Tuesday, Australia’s Bureau of Meteorology said La Nina weather will likely emerge after August only.
Cooling slows
It said climate models suggested that sea surface temperatures (SSTs) in the central tropical Pacific are likely to continue to cool for at least the next 2 months. “From September, four of seven climate models suggest SSTs are likely to remain at neutral ENSO levels, and the remaining three suggest the possibility of SSTs reaching La Nina levels (below −0.8 °C),” it said in its Climate Driver Update.
The Copernicus Climate Change Service (C3S), the earth observation component of the European Union’s Space programme, said in a press release on Monday that temperatures were below average over the eastern equatorial Pacific, indicating a developing La Nina. However, air temperatures over the ocean remained at an unusually high level over many regions.
BoM said, “During June, the rate and extent of cooling both at the surface and at depth has slowed. Cloud and surface pressure patterns are currently ENSO-neutral.”