Newstalk ZB
By Kate Newton of RNZ An El Nino that peaks over the New Zealand summer is now very likely, bringing with it the risks of drought, extremely hot days and wildfire. Earth Sciences New Zealand and the World Meteorological Organisation (WMO) are warning that an El Nino event is developing, fuelled by warmer-than-usual waters in the tropical Pacific. A WMO update issued overnight said there was an 80% chance of an official El Nino event emerging during winter, with a higher probability of that continuing until at least November. ESNZ’s latest seasonal climate outlook puts the prospect even higher, with a 95% chance of El Nino conditions forming over winter. “Peak El Nino conditions are expected to occur during the austral summer of 2026-27, with the potential for this event to have significant impacts,” the outlook summary said. El Nino forms when there are higher-than-usual temperatures in the eastern Pacific, causing trade winds to die down. That means clouds form and rain falls on that side of the ocean, rather than closer to Australia and New Zealand. The heavy rain events that brought flooding and landslides to many parts of the North Island at the start of the year would become less frequent over the next few months, ESNZ said. Instead, “areas hit by heavy rainfall are expected to shift to generally drier-than-usual conditions”. “The prospect of below normal winter rainfall in several regions is likely to translate to below-normal groundwater recharge, creating challenges for water-reliant sectors.” That could also be accompanied by “unusually windy conditions”. ESNZ principal forecasting scientist Chris Brandolino said El Nino was “well and truly on its way”. “All the makings for a rather profound and intense event are there as well.” While every El Nino was different, the general pattern was for wetter conditions in the southwest of the South Island, and drier, windier conditions in most other parts of the country, especially the east and northeast. That would not be welcome news for places such as Canterbury and Hawke’s Bay, which had already had an unusually dry past few months, Brandolino said. It would likely affect groundwater recharge over winter, which would have flow-on consequences for the growing season. “One [dry] month, two months, not great – but you can probably deal with it. But you start getting three months, five months, six months, when the rainfall is inadequate [and] then you really start to run into problems,” he said. “You’re coming off a dry winter and now you’re looking at the prospect of a dry spring or dry summer ... and then you throw in really warm temperatures as you get into spring.” That, together with higher winds and dry conditions, could also increase the risk of out-of-season fires or an early start to the fire season. Temperatures during El Nino could be “spiky”, he said, and that was set against a background of warming temperatures caused by climate change. “As we move through spring and summer there’s a distinct possibility we could see some pretty hot days.” He urged people who might be affected by dry conditions, such as farmers and horticulturists, and those reliant on tank water, to think back to previous El Nino conditions or droughts and start making a plan now. The outlook could still change for the better or worse. “It’s important for people to stay on top of the forecasts, particularly for those people in a water-reliant sector.” - RNZ
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