In March, the US National Oceanic and Atmospheric Administration (NOAA) predicted that the 2023-2024 El Nino phenomenon was gradually ending and La Nina could appear soon after.
A month earlier, NOAA released data showing that a cooling pattern in the equatorial Pacific Ocean has about a 55% chance of forming during the summer months.
By April, NOAA raised its forecast to 85% chance that El Nino would end by June (which it did) and that La Nina could emerge by late August. The Australian Bureau of Meteorology also joined in the forecast, issuing an official La Nina warning in May.
Historically, there have only been 10 times when El Nino has transitioned to La Nina in the same year, but 2024 is expected to be the 11th. Those living on the US West Coast have reason to brace themselves for a tumultuous winter if this scenario occurs.
However, forecasts began to change.
In July, NOAA meteorologists adjusted the message, saying the chances of La Nina occurring were decreasing: 70% for August-October, and 79% for November-January.
By October, NOAA was still predicting a La Nina winter but said it would not be as strong. There have only been four times when La Ninas have formed this late in the year.
“La Nina is forecast to occur between September and November (with a 60% chance) and could last until January and March 2025. The La Nina warning is still in effect,” NOAA announced on social network X.
However, with just 11 days left until 2025, La Nina has yet to appear. So what happened?
Surprisingly, NOAA forecasters kept their La Nina forecast unchanged, with a 59% chance of it forming “in the near term.”
“The atmosphere has been La Nina-like for a long time, but the ocean is not, at least by traditional measurements of sea surface temperatures,” NOAA writes bluntly, adding that strong trade winds will cool the surface waters and “push warm water into the western Pacific.” When that happens (which is expected soon), conditions in the Pacific will reach La Nina levels.
“However, even if we do issue a La Nina warning in the near term, it is likely to be a weak event,” NOAA forecasters said.
