A major climate pattern shift has finally happened. Will it change our weather?
First predicted to form last summer, climate troublemaker La Niña has developed at last, federal climate scientists announced Thursday morning. However, the pattern is a weak one, and isn't supposed to be around too long.
La Niña is a part of a natural climate cycle officially known as El Niño – Southern Oscillation, called ENSO by scientists. The cycle swings between warmer and cooler seawater in a region along the equator in the tropical Pacific. La Niña is marked by cooler-than-average ocean water in the region.
"We finally got to La Niña!" National Weather Service meteorologist Erica Grow Cei said in an email to Paste BN. La Niña conditions were finally officially met this week, the National Oceanic and Atmospheric Administration (NOAA) said.
But those conditions are only expected to stick around until the spring, "with a transition to ENSO-neutral likely during March-May 2025," NOAA said in a forecast released Thursday.
What is La Niña?
La Niña is a natural climate pattern marked by cooler-than-average seawater in the central and eastern Pacific Ocean. When the water cools at least 0.9 degree Fahrenheit below average for three straight months, a La Niña is declared.
"While this may sound like a small change in temperature, it can cause significant changes in the weather patterns around the globe," AccuWeather meteorologist Brian Lada said.
It is one of the main drivers of weather in the United States, especially during the late fall, winter and early spring. It's the opposite to the more well-known El Niño, which occurs when Pacific Ocean water is at least 0.9 degree warmer than average for three months.
What took so long for this La Niña to develop?
"Simply put, we don't know exactly, but it will make for interesting research I am sure," said NOAA meteorologist Tom DiLiberto, in an email to Paste BN. "The model forecasts that we rely upon were clearly too cold when they were run earlier this year."
La Niña had first been predicted to form in the summer, forecasters said.
What does this weak La Niña mean for the rest of our winter weather in the US?
The national forecast is still the same, with overall dry weather expected across the southern U.S. and wetter-than-average weather in the Northwest.
"We’re not expecting any major changes to the winter/spring impacts that forecasters have already been predicting in their seasonal temperature and precipitation outlooks," DiLiberto said.
Was NOAA's winter forecast accurate?
"I'm always a bit nervous to make claims about winter with months left before the season is over," he added. "We've seen in past years how one month can impact the seasonal pattern."
"But so far this winter, the patterns seen over the U.S., including drier than average conditions across the southern tier, and wetter than average conditions in the Pacific Northwest, are consistent with the historically expected La Niña pattern, and also generally consistent with the winter outlook issued in November 2024," DiLiberto said.
Dry conditions across the Southwest helped fuel the wildfires that are currently scorching southern California. All of Los Angeles County is in a drought, according to the most recent U.S. Drought Monitor released Thursday.