La Niña has not yet returned as hurricane forecasters had predicted | Hurricane Center

There is still about a month and a half left in the 2024 Atlantic hurricane season, and La Niña has not yet appeared, although early forecasts predicted a return in late summer.

That's good news for the Gulf Coast and other storm-weary regions because La Niña is associated with more tropical activity in the Atlantic Ocean, according to National Weather Service Climate Prediction Center forecaster Matthew Rosencrans.

“At this point, it doesn’t look like we’re going to have a really intense November,” Rosencrans said.

In its latest Oct. 10 update on the so-called El Niño-Southern Oscillation (ENSO) cycle, the Climate Prediction Center said the tropical Pacific continues to reflect the neutral conditions often seen during the El Niño-El Niño transition period La Nina.

According to the Climate Prediction Center, the chance of La Niña returning sometime before the end of November is still about 60%, although meteorologists expect that if such conditions do occur, they will be “weak” and not last long.

La Niña is the cool phase of the ENSO cycle, a pattern of alternating warmer and cooler surface waters in the tropical Pacific. Rising warm air in the tropics drives global atmospheric circulation, including the jet stream, storm tracks, and temperature and rainfall patterns.

La Niña tends to promote the formation and intensification of Atlantic hurricanes by reducing vertical wind shear over the Caribbean and tropical Atlantic. Wind shear can tear storms apart as they begin to form.

Before the start of the 2024 hurricane season on June 1, hurricane researchers and forecasters widely predicted that La Niña would return with full force after a record multi-year period of warmer water in the eastern Pacific, also known as El Niño.

The shift to La Niña was expected during peak hurricane season, which has historically been between mid-August and early October. According to Rosencrans, the Climate Prediction Center said in its spring outlook that there is a 77% chance of La Nina occurring sometime in August, September or October.

This, along with record-breaking temperatures in the Gulf of Mexico, led to alarming preseason forecasts that predicted 2024 would be one of the most active hurricane seasons in history.

Instead, Rosencrans said neutral conditions continued and the chances of La Niña returning by the end of the season had decreased.

“If anything, we will probably hit the low end of our projections,” Rosencrans said. “There’s no way we’re going to continue the rapid pace we’re at.”

The reasons why neutral conditions persisted are not simple and there are countless factors that influence the ENSO cycle, Rosencrans said, including both long-term climate patterns and short-term weather conditions. That can make it difficult to predict early how ENSO will evolve, he said, and ENSO forecasts ahead of hurricane season have earned a reputation for being inaccurate.