The Child comes out. Will dry conditions return to California?

After a year of dominance, El Niño's wrath has come to an end, but its weather-shaking counterpart, La Niña, is hot on its heels and could signal a return to dryness in California.

El Niño is the warm phase of the El Niño Southern Oscillation, sometimes called ENSO. The weather pattern in the tropical Pacific is the largest driver of weather conditions around the world and has been actively altering global temperatures and precipitation patterns since its arrival last summer.

Among other effects, the El Niño phenomenon contributed to months of record-breaking global ocean temperatures, extreme heat stress on coral reefs, drought in the Amazon and Central America, and record-breaking atmospheric rivers on the US West Coast. ., the Oceanic National Park and the Atmospheric Administration said in its latest ENSO update.

The system now offers a brief respite as it has adopted a “neutral” pattern, but it will not remain that way for long.

There is a 65% chance that La Niña will develop between July and September and persist through the Northern Hemisphere winter, NOAA said. There is an 85% chance that between November and January.

A La Niña event generally means a drier winter across the southern United States.

(Paul Duginski / Los Angeles Times)

Along the West Coast, and in Southern California in particular, La Niña is often associated with colder, drier conditions. La Niña was last present during the state's three driest years on record (2020 to 2022), which saw devastating drought conditions and unprecedented water restrictions for millions of people.

Bill Patzert, a retired climatologist at NASA's Jet Propulsion Laboratory in La Cañada-Flintridge, noted that Southern California has experienced 25 years of weak to strong La Niñas since 1950, when modern record-keeping began. Nineteen of those years have been drier than normal.

“So for Angelenos, La Nina loads the dice for a drier than average winter and is rightly often called 'the Drought Diva,'” he said.

“But it's not a sure thing,” Patzert added. “La Niña can surprise us. “It’s still a game of chance, but firefighters, water managers and farmers would do well to be prepared.”

In fact, state water managers are preparing, but for wet or dry conditions later this year, according to Jeanine Jones, interstate resources manager for the California Department of Water Resources.

This is because La Niña is just one of many factors that can influence California's climate, and its results are never a guarantee.

“Historically, most La Niña years have been dry, but by itself it's not a good predictor because there are other things going on,” Jones said. “We always like to say that in any given year, because of the extreme variability of precipitation in California, we should prepare for a wet or dry year.”

Among those preparations are ongoing discussions about a state climate bond, which would provide more financial assistance to help prepare for both extremes, he said. State officials also continue to implement Gov. Gavin Newsom's strategy, unveiled in 2022, for a warmer, drier future.

But images of the most recent drought remain fresh in the memories of many Californians, including brown, dead grasses and dangerously low water levels in Lake Oroville and Lake Mead.

Jones noted that the severe water restrictions Southern California experienced during that drought were due to State Water Project cutbacks as well as long-term drought conditions on the Colorado River. The good news is that California reservoirs are currently at above-average levels following two consecutive wet winters driven by El Niño.

“Most water users in California are equipped and accustomed to dealing with a single dry year,” he said. “When conditions persist for several dry years in a row, life becomes more difficult.”

La Niña is not just a factor when it comes to precipitation. The pattern could also indicate a slight break with the phenomenon caused by El Niño. Record global temperatures that have taken over the planet over the past 12 months, NOAA officials said.

However, long-term warming trends driven by climate change could still place 2024 among the hottest years on record, according to Michelle L'Heureux, a climate scientist at NOAA's Climate Prediction Center.

“La Niña generally results in colder global mean temperatures,” L'Heureux said in an email. “However, we are still feeling the effects of the previous El Niño on global average temperatures, so it is not entirely clear where it will rank this year, other than it will probably be in the top five. Because climate change is increasing temperatures over time, we can hope that La Niña can make a dent in that upward trend, but it probably won't be much.

La Niña also poses other challenges, including links to the forecast active Atlantic hurricane seasonwhich is expected to spawn up to 25 named storms.

L'Heureux said La Niña's immediate effects will be limited since ENSO has “minimal influence on summer temperature and precipitation anomalies in the United States,” and that its impacts don't really start to emerge until the fall or winter. .

NOAA's latest winter outlook currently points to warmer, drier conditions across the southern half of the United States, including Southern California. Parts of the Midwest, Montana, Idaho and Washington could experience wetter weather.

“The tilt toward higher chances of below-average precipitation and above-average temperatures for the Southwest and California is fairly typical of a La Niña-influenced winter,” L'Heureux said.

It's too early to say how strong La Nina is likely to be, as a wide range of possible outcomes are still in play, forecasters said.

In fact, it is rare for ENSO to change from El Niño to La Niña in a year, something that happens only 10 times in the historical record, Rebecca Lindsey of NOAA's Climate Program Office wrote on the agency's blog.

Of those cases, four of the six “strong” El Niño evolved into strong La Niñas. But the strongest El Niño of all ended up becoming the weakest La Niña, so “it's complicated,” Lindsey wrote, noting that the strength of the next event will become clearer as it gets closer.

JPL's Patzert also cautioned that La Niña is not the only player in predicting precipitation and temperature, and that global warming “is surely impacting the impacts of El Niño and La Niña in ways that are not yet understood.” completely”.

“The reach of La Niña, reinforced by climate change, is global,” he said. “In many parts of the world, last year's rainfall and temperature patterns can reverse from droughts to floods, from rains to wildfires, from economic benefits to devastating disasters. La Niña is a big problem.”