TOKYO - The Japan Meteorological Agency (JMA) announced that an El Niño phenomenon is believed to have developed this spring, warning that Japan is likely to experience above-average temperatures nationwide this summer despite the climate pattern's traditional association with cooler summers.
El Niño is a phenomenon in which sea surface temperatures remain higher than normal for about a year across the equatorial Pacific, stretching from off the coast of Peru in South America to the central Pacific Ocean.
According to the JMA, the previous El Niño event lasted from the spring of 2023 through the spring of 2024, making this the first occurrence in about two years.
Although El Niño has generally been associated with cooler summers in Japan, the effects of global warming in recent years have increased the likelihood of extreme heat even during El Niño years. The summer of 2023, when the previous El Niño event was underway, was tied for the second-hottest summer on record in Japan.
For this summer, the JMA said atmospheric conditions resemble those seen in 2023. Even when forecasts account for the development of El Niño, the westerly jet stream is expected to remain farther north than usual, allowing the Pacific high-pressure system to strengthen and extend over Japan. As a result, temperatures are expected to remain above normal across the country.
The agency urged the public to take precautions against heatstroke and other heat-related illnesses.
El Niño may also influence typhoon activity. The JMA said typhoons tend to form farther south during El Niño events, causing them to travel over warmer ocean waters for longer periods. This can extend their lifespan and make it easier for them to intensify, often resulting in lower central atmospheric pressure.
The El Niño phenomenon is expected to persist through autumn.
A JMA official noted that El Niño is a long-lasting climate pattern that often strengthens toward winter. When El Niño conditions are present, Japan is generally more likely to experience a warmer-than-average winter, the official said.
Source: TBS
