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San Francisco Chronicle
2 days ago
- Climate
- San Francisco Chronicle
La Niña is brewing. Here's what it means for California weather
Forecasters expect La Niña conditions to develop this fall and winter, according to an update Thursday by the National Weather Service's Climate Prediction Center. The agency has issued a La Niña watch, indicating that conditions in the tropical Pacific Ocean are favorable for the climate pattern's formation in the coming months. La Niña is defined by cooler than average sea surface temperatures in the central and eastern Pacific along the equator. The ocean waters affect atmospheric activity, tilting the odds toward drier than normal conditions in Southern California and wetter than average conditions to the far north, especially in the winter. The Climate Prediction Center's latest seasonal outlook for November, December and January hints at such a pattern. But the forecast isn't guaranteed: La Niña may not emerge at all. And, even if it does, other factors could outweigh La Niña's influence. The recurring climate phenomenon involving La Niña and its counterpart, El Niño, is 'the great nudger,' said Climate Prediction Center scientist Michelle L'Heureux. 'It won't always be successful.' Sea surface temperatures in the central and eastern tropical Pacific are currently near normal, following a brief stretch of La Niña conditions last winter. The Climate Prediction Center outlook gives a 53% chance that La Niña conditions will develop in the fall. Forecasters expect the cooler than average waters to disappear shortly thereafter, with sea surface temperatures returning to near normal, or neutral, conditions in a few months. During the most recent fall and winter, California precipitation mimicked the expected La Niña pattern: Northern California logged above-average rain, while southern regions remained parched. A lack of rain in Los Angeles set the stage for the devastating Palisades and Eaton fires, and more recent blazes that broke out in the region. But during the 2022-23 La Niña winter, Central and Southern California faced a flurry of storms fueled by atmospheric rivers, ribbons of water vapor in the sky. Downpours brought flooding across California and snowstorms produced one of the state's largest snowpacks on record. La Niña and El Niño aren't the only factors behind California weather. A recent study reported atmospheric rivers are 'wild cards' that can disrupt the patterns expected during La Niña or El Niño years. 'One or two atmospheric rivers can turn it into a wet year, but a weak atmospheric river season can turn it into a dry year,' said author Rosa Luna-Niño, a postdoctoral scholar at UC San Diego's Scripps Institution of Oceanography, in a statement. 'This means we can't trust El Niño and La Niña completely to make accurate water year predictions.' L'Heureux explained that La Niña's influence is on seasonal time scales, rather than the day-to-day time scale of individual weather events. It's 'playing on a slightly different ball field,' L'Heureux said. One effect, for example, could be shifting atmospheric rivers slightly northward over the course of an entire season. Signs that La Niña could potentially form have appeared in the past month, with shifts in ocean temperatures and wind patterns, L'Heureux said. But how the coming months will play out remains an open question. 'We need to wait … to see if a significant La Niña is going to develop this winter,' said Shang-Ping Xie, a climate scientist at UC San Diego's Scripps Institution of Oceanography, by email.
CNN
01-05-2025
- Climate
- CNN
La Niña is dead. Here's what to expect in the coming months
The short-lived reign of La Niña has come to an end. La Niña – a natural climate pattern that can influence weather worldwide – arrived at the start of this year but had a very short and odd life. The atmosphere first started to take on a La Niña look last fall, but the cooler than average ocean temperatures in the tropical Pacific Ocean that typically mark its arrival didn't get with the program until the end of the year. Once they finally did, they only maintained La Niña levels for a few months. Now, neither La Niña nor its counterpart El Niño are present and a so-called neutral phase has begun, according to a new National Oceanic and Atmospheric Administration report. This neutral phase is forecast to last through the rest of spring, summer and into at least early fall. Forecasters closely monitor La Niña and El Niño because they influence global weather in a way that's largely consistent and predictable well in advance. But La Niña's demise doesn't flip an on-off switch in the atmosphere. Its fingerprints will linger even if they could be limited by its duration and strength, according to Michelle L'Heureux, a climate scientist with the Climate Prediction Center. It's 'very difficult' to quantify exactly how long and to what extent La Niña's ghost could stick around, L'Heureux said. Months elapsed before the impact of an extremely strong El Niño dwindled. It played a part in record-warm global temperatures the last two years. What could happen to the weather in the coming months without La Niña and El Niño is less clear-cut, but forecasters are already making predictions. There will not be a clear influence from El Niño or La Niña to help guide forecasts on how this upcoming Atlantic hurricane season – which starts in June – will unfold. Neutral conditions basically have coin-flip odds to persist through the peak of hurricane season this year, which stretches from mid-August to mid-October. La Niña typically leads to a much more active hurricane season while El Niño is more prone to suppressing hurricane activity – except for in 2023. Forecasters need to factor in other influences without either heavy-hitter. Lingering abnormal ocean warmth and a planet warming due to fossil fuel pollution have at least one group of experts thinking this hurricane season will be a busy one. Oceans are incredibly slow to cool, especially since about 90% of the world's excess heat produced by burning planet-heating fossil fuels are stored in them. Global ocean temperatures were at record highs for large parts of 2023 and 2024. El Niño transitioned to neutral conditions shortly before the start of last year's incredibly active hurricane season. Extremely warm oceans churned out 18 named storms, including 11 hurricanes. Five of those hurricanes – including now retired Helene and Milton – slammed into the US. Neutral conditions also offer a somewhat muddled influence on upcoming temperature and precipitation patterns in the US, especially during the summer, but there's still a lot of time for forecasters to zero in. The latest forecasts from the Climate Prediction Center show plenty of above-average warmth coming through the reminder of spring and into summer. Above average temperatures are forecast nearly everywhere in the US aside from the Pacific Northwest and parts of the Northern Tier through June. Above average temperatures could spread across the entire Lower 48 for summer. Temperatures continue to rise globally, and there are more frequent and extreme bouts of heat from planet-warming pollution. That, along with an expansive drought in parts of the US, are the reasons for the toasty forecast over the next several months. Prolonged heat and dry weather tend to get stuck in a loop where each factor continuously makes the other worse – something that unfolded to the extreme last summer.
CNN
10-04-2025
- Climate
- CNN
La Niña is dead. Here's what to expect in the coming months
Hurricanes Storms Climate changeFacebookTweetLink Follow The short-lived reign of La Niña has come to an end. La Niña – a natural climate pattern that can influence weather worldwide – arrived at the start of this year but had a very short and odd life. The atmosphere first started to take on a La Niña look last fall, but the cooler than average ocean temperatures in the tropical Pacific Ocean that typically mark its arrival didn't get with the program until the end of the year. Once they finally did, they only maintained La Niña levels for a few months. Now, neither La Niña nor its counterpart El Niño are present and a so-called neutral phase has begun, according to a new National Oceanic and Atmospheric Administration report. This neutral phase is forecast to last through the rest of spring, summer and into at least early fall. Forecasters closely monitor La Niña and El Niño because they influence global weather in a way that's largely consistent and predictable well in advance. But La Niña's demise doesn't flip an on-off switch in the atmosphere. Its fingerprints will linger even if they could be limited by its duration and strength, according to Michelle L'Heureux, a climate scientist with the Climate Prediction Center. It's 'very difficult' to quantify exactly how long and to what extent La Niña's ghost could stick around, L'Heureux said. Months elapsed before the impact of an extremely strong El Niño dwindled. It played a part in record-warm global temperatures the last two years. What could happen to the weather in the coming months without La Niña and El Niño is less clear-cut, but forecasters are already making predictions. There will not be a clear influence from El Niño or La Niña to help guide forecasts on how this upcoming Atlantic hurricane season – which starts in June – will unfold. Neutral conditions basically have coin-flip odds to persist through the peak of hurricane season this year, which stretches from mid-August to mid-October. La Niña typically leads to a much more active hurricane season while El Niño is more prone to suppressing hurricane activity – except for in 2023. Forecasters need to factor in other influences without either heavy-hitter. Lingering abnormal ocean warmth and a planet warming due to fossil fuel pollution have at least one group of experts thinking this hurricane season will be a busy one. Oceans are incredibly slow to cool, especially since about 90% of the world's excess heat produced by burning planet-heating fossil fuels are stored in them. Global ocean temperatures were at record highs for large parts of 2023 and 2024. El Niño transitioned to neutral conditions shortly before the start of last year's incredibly active hurricane season. Extremely warm oceans churned out 18 named storms, including 11 hurricanes. Five of those hurricanes – including now retired Helene and Milton – slammed into the US. Neutral conditions also offer a somewhat muddled influence on upcoming temperature and precipitation patterns in the US, especially during the summer, but there's still a lot of time for forecasters to zero in. The latest forecasts from the Climate Prediction Center show plenty of above-average warmth coming through the reminder of spring and into summer. Above average temperatures are forecast nearly everywhere in the US aside from the Pacific Northwest and parts of the Northern Tier through June. Above average temperatures could spread across the entire Lower 48 for summer. Temperatures continue to rise globally, and there are more frequent and extreme bouts of heat from planet-warming pollution. That, along with an expansive drought in parts of the US, are the reasons for the toasty forecast over the next several months. Prolonged heat and dry weather tend to get stuck in a loop where each factor continuously makes the other worse – something that unfolded to the extreme last summer.
Yahoo
10-04-2025
- Climate
- Yahoo
La Niña's odd, short life is over. Here's what could happen to the weather without it and El Niño
The short-lived reign of La Niña has come to an end. La Niña – a natural climate pattern that can influence weather worldwide – arrived at the start of this year but had a very short and odd life. The atmosphere first started to take on a La Niña look last fall, but the cooler than average ocean temperatures in the tropical Pacific Ocean that typically mark its arrival didn't get with the program until the end of the year. Once they finally did, they only maintained La Niña levels for a few months. Now, neither La Niña nor its counterpart El Niño are present and a so-called neutral phase has begun, according to a new National Oceanic and Atmospheric Administration report. This neutral phase is forecast to last through the rest of spring, summer and into at least early fall. Forecasters closely monitor La Niña and El Niño because they influence global weather in a way that's largely consistent and predictable well in advance. But La Niña's demise doesn't flip an on-off switch in the atmosphere. Its fingerprints will linger even if they could be limited by its duration and strength, according to Michelle L'Heureux, a climate scientist with the Climate Prediction Center. It's 'very difficult' to quantify exactly how long and to what extent La Niña's ghost could stick around, L'Heureux said. Months elapsed before the impact of an extremely strong El Niño dwindled. It played a part in record-warm global temperatures the last two years. What could happen to the weather in the coming months without La Niña and El Niño is less clear-cut, but forecasters are already making predictions. There will not be a clear influence from El Niño or La Niña to help guide forecasts on how this upcoming Atlantic hurricane season – which starts in June – will unfold. Neutral conditions basically have coin-flip odds to persist through the peak of hurricane season this year, which stretches from mid-August to mid-October. La Niña typically leads to a much more active hurricane season while El Niño is more prone to suppressing hurricane activity – except for in 2023. Forecasters need to factor in other influences without either heavy-hitter. Lingering abnormal ocean warmth and a planet warming due to fossil fuel pollution have at least one group of experts thinking this hurricane season will be a busy one. Oceans are incredibly slow to cool, especially since about 90% of the world's excess heat produced by burning planet-heating fossil fuels are stored in them. Global ocean temperatures were at record highs for large parts of 2023 and 2024. El Niño transitioned to neutral conditions shortly before the start of last year's incredibly active hurricane season. Extremely warm oceans churned out 18 named storms, including 11 hurricanes. Five of those hurricanes – including now retired Helene and Milton – slammed into the US. Neutral conditions also offer a somewhat muddled influence on upcoming temperature and precipitation patterns in the US, especially during the summer, but there's still a lot of time for forecasters to zero in. The latest forecasts from the Climate Prediction Center show plenty of above-average warmth coming through the reminder of spring and into summer. Above average temperatures are forecast nearly everywhere in the US aside from the Pacific Northwest and parts of the Northern Tier through June. Above average temperatures could spread across the entire Lower 48 for summer. Temperatures continue to rise globally, and there are more frequent and extreme bouts of heat from planet-warming pollution. That, along with an expansive drought in parts of the US, are the reasons for the toasty forecast over the next several months. Prolonged heat and dry weather tend to get stuck in a loop where each factor continuously makes the other worse – something that unfolded to the extreme last summer.
CNN
10-04-2025
- Climate
- CNN
La Niña's odd, short life is over. Here's what could happen to the weather without it and El Niño
The short-lived reign of La Niña has come to an end. La Niña – a natural climate pattern that can influence weather worldwide – arrived at the start of this year but had a very short and odd life. The atmosphere first started to take on a La Niña look last fall, but the cooler than average ocean temperatures in the tropical Pacific Ocean that typically mark its arrival didn't get with the program until the end of the year. Once they finally did, they only maintained La Niña levels for a few months. Now, neither La Niña nor its counterpart El Niño are present and a so-called neutral phase has begun, according to a new National Oceanic and Atmospheric Administration report. This neutral phase is forecast to last through the rest of spring, summer and into at least early fall. Forecasters closely monitor La Niña and El Niño because they influence global weather in a way that's largely consistent and predictable well in advance. But La Niña's demise doesn't flip an on-off switch in the atmosphere. Its fingerprints will linger even if they could be limited by its duration and strength, according to Michelle L'Heureux, a climate scientist with the Climate Prediction Center. It's 'very difficult' to quantify exactly how long and to what extent La Niña's ghost could stick around, L'Heureux said. Months elapsed before the impact of an extremely strong El Niño dwindled. It played a part in record-warm global temperatures the last two years. What could happen to the weather in the coming months without La Niña and El Niño is less clear-cut, but forecasters are already making predictions. There will not be a clear influence from El Niño or La Niña to help guide forecasts on how this upcoming Atlantic hurricane season – which starts in June – will unfold. Neutral conditions basically have coin-flip odds to persist through the peak of hurricane season this year, which stretches from mid-August to mid-October. La Niña typically leads to a much more active hurricane season while El Niño is more prone to suppressing hurricane activity – except for in 2023. Forecasters need to factor in other influences without either heavy-hitter. Lingering abnormal ocean warmth and a planet warming due to fossil fuel pollution have at least one group of experts thinking this hurricane season will be a busy one. Oceans are incredibly slow to cool, especially since about 90% of the world's excess heat produced by burning planet-heating fossil fuels are stored in them. Global ocean temperatures were at record highs for large parts of 2023 and 2024. El Niño transitioned to neutral conditions shortly before the start of last year's incredibly active hurricane season. Extremely warm oceans churned out 18 named storms, including 11 hurricanes. Five of those hurricanes – including now retired Helene and Milton – slammed into the US. Neutral conditions also offer a somewhat muddled influence on upcoming temperature and precipitation patterns in the US, especially during the summer, but there's still a lot of time for forecasters to zero in. The latest forecasts from the Climate Prediction Center show plenty of above-average warmth coming through the reminder of spring and into summer. Above average temperatures are forecast nearly everywhere in the US aside from the Pacific Northwest and parts of the Northern Tier through June. Above average temperatures could spread across the entire Lower 48 for summer. Temperatures continue to rise globally, and there are more frequent and extreme bouts of heat from planet-warming pollution. That, along with an expansive drought in parts of the US, are the reasons for the toasty forecast over the next several months. Prolonged heat and dry weather tend to get stuck in a loop where each factor continuously makes the other worse – something that unfolded to the extreme last summer.
