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Experts anticipate shift from El Niño to La Niña this summer

The transition will impact precipitation, storms and temperature distributions worldwide.

Ocean Waves Sunset
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According to the latest climate forecasts by the National Oceanic and Atmospheric Administration (NOAA) and the National Weather Service, a shift from the current El Niño conditions to ENSO-neutral is expected within the next month. There is also a significant probability that La Niña could develop later in the year, with chances increasing through the summer and early fall.

During April 2024, a mixture of below-average and above-average sea surface temperatures (SSTs) was observed across the equatorial Pacific. While small regions of the eastern Pacific experienced cooler than average SSTs, warmer temperatures prevailed across the majority of the equatorial Pacific. This temperature distribution has contributed to the weakening of El Niño conditions.

The latest data shows weekly Niño index values ranging from +0.5°C to +0.8°C across various regions, signaling a continuing transition toward ENSO-neutral conditions. Subsurface ocean temperatures remained below average throughout April, extending from the Date Line to the eastern Pacific, indicating a potential setup for La Niña development.

Atmospheric conditions also reflect this transition, with easterly wind anomalies noted over the western equatorial Pacific and average conditions in upper-level winds. Convection patterns were reported as near average across the equatorial Pacific and Indonesia.

Forecasts from dynamic models provided by climate experts indicate a 49% chance of La Niña developing as early as June-August 2024, with a higher likelihood of 69% during the July-September period. These forecasts suggest that La Niña could persist through the Northern Hemisphere winter, following the typical pattern where strong El Niño events are often succeeded by La Niña.

Understanding El Niño and La Niña

El Niño and La Niña are significant climate phenomena that form part of the El Niño-Southern Oscillation (ENSO) cycle, impacting global weather, ecosystems, and economies. These events typically occur every two to seven years and can last from nine months to several years.

El Niño: Characterized by weakened trade winds and warmer than usual water being pushed back towards the Americas, El Niño conditions disrupt typical weather patterns, leading to wetter conditions in the U.S. Gulf Coast and Southeast and drier, warmer conditions in the northern U.S. and Canada. This warming disrupts marine life due to decreased upwelling, which normally brings nutrient-rich cold water to the surface, supporting a rich marine ecosystem.

La Niña: Often considered the counterpart to El Niño, La Niña involves stronger than usual trade winds pushing warmer water towards Asia and enhancing upwelling off the west coast of the Americas. This results in colder, nutrient-rich waters that affect weather patterns by pushing the jet stream northward, often leading to drought in the southern U.S. and heavier rains and potential flooding in the Pacific Northwest and Canada. La Niña conditions also enrich the marine environment off the Pacific coast, supporting more marine life and attracting cold-water species.

This transition and the potential for La Niña have significant implications for global weather patterns, affecting precipitation, storms, and temperature distributions worldwide. The next detailed ENSO Diagnostics Discussion from NOAA is scheduled for June 13, 2024, which will provide further updates on these evolving climate conditions. Meanwhile, updated oceanic and atmospheric data continue to be available on the Climate Prediction Center’s website.

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