Climate troublemaker La Niña hasn’t arrived yet, but it’s underway, federal forecasters said in a report released Thursday morning.
In fact, National Oceanic and Atmospheric Administration forecasters give this weather pattern an 85% chance of forming by late fall. “We are very confident that La Niña will develop by this fall,” NOAA meteorologist Nat Johnson told USA TODAY. Once it occurs, it is thought to persist into the next winter and will affect the weather in the United States during the coldest months.
An even more pressing concern is that there is a 69% chance of developing the disease by summer (July through September), NOAA said. This is important because a full-blown La Niña event could worsen the intensity of the Atlantic hurricane season, which typically centers around September.
What is La Niña?
La Niña is a natural climate pattern characterized by lower-than-average seawater in the central and eastern Pacific Ocean. La Niña is declared when water temperatures are at least 0.9 degrees Fahrenheit below average for three consecutive months.
Amazingly, even that small amount is enough to influence weather and climate patterns in the United States and around the world.
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The cycle between La Niña and its “brother” El Niño is extremely important for agriculture around the world. While El Niño generally brings wetter conditions to the Americas, La Niña has the opposite effect.
Is El Niño over?
Although it still technically still has an impact, it is rapidly fading and will soon be replaced by what is known as an “ENSO neutral” state, an intermediate stage between La Niña and El Niño. NOAA’s forecast “supports an imminent transition to ENSO-neutral conditions, with La Niña developing from July to September 2024 and continuing through the Northern Hemisphere winter.”
The entire natural climate cycle, officially known by climate scientists as the “El Niño-Southern Oscillation” (ENSO), is a seesaw dance of warm and cold ocean waters in the central Pacific Ocean.
Is this an unusually slow transition from one state to another?
“In fact, this transition seems to be happening pretty quickly,” Johnson told USA TODAY. “While it is unlikely that ENSO neutrality lasts for many seasons before La Niña begins, in some cases we may experience more than a year before transitioning to La Niña.”
“The strength of El Niño is likely the main factor why this transition is so fast,” he added. “After a strong El Niño, the release of heat from the tropical Pacific Ocean tends to be more dramatic, so it is not uncommon for a strong El Niño to quickly transition into a La Niña.”
What is La Niña winter?
Forecasters expect the La Niña phenomenon to continue into next winter. According to NOAA’s Climate Prediction Center, a typical La Niña winter in the United States brings cold and snow to the Northwest and unusually dry conditions to most of the southern tier of the United States. The Southeast and mid-Atlantic also tend to experience warmer-than-average temperatures during La Niña winters.
