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Our seas are experiencing their third heat wave in four years, which will also raise air temperatures, according to Niwa.
Meteorologist Ben Noll said Northland’s oceans are registering temperatures between 18 and 21 degrees Celsius, that is, 1.6 degrees Celsius above average for this time of year. These types of measurements officially put the region in a marine heat wave.
Because warmer seas translate to warmer air, this could be one of the first signs that another scorching summer is coming, along with potentially supercharged storms.
Northland swimmers and fishermen may have already noticed the effects, Noll said. “You can go into the ocean right now in the northern part of the country and think, ‘Wow, that’s not that great.’
Last month’s execution of high-pressure systems brought sunny and calm weather, which meant that the upper ocean waters remained settled and absorbed heat, Noll said.
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“Now that we get to November, you can see that ocean temperatures have kept that warm,” he said. “It’s fair to say that if warm ocean temperatures persist as we get closer to summer, we are probably also in a fairly warm summer here on land.
Temperatures have already risen, Noll said. “The airflow patterns in November are coming from the northeast and northwest and that has helped to draw warmer air masses from the subtropics and tropics to the north of the country. That has kept our nighttime temperatures warmer than average and, at times, our daytime temperatures quite warm as well. “
Dominico Zapata / Things
This month, much higher than average sea surface temperatures have been recorded in the oceans of the upper North Island.
The Pacific is in the La Niña weather pattern at the moment, so these weather conditions are likely to continue.
So far, Northland waters are the only ones to have reached marine heat wave status. This means that 90 percent of the time, the region’s seas are colder than the temperatures now recorded.
But other regions may be on the way. The oceans east and west of the South Island and the east coast of the North Island are 1.1 ° C warmer than normal, Noll said.
“We believe that there is a medium to high probability that other regions of coastal waters will reach marine heat wave status in the next few weeks or months.”
However, it is not all good news for tourists, he added. “These warm waters are fuel for the climatic systems that pass over them. In early 2018, three former tropical cyclones passed near New Zealand, two of which were quite shocking, so that’s something to consider as well. “
BRADEN FASTIER / Things
In 2018, the former tropical cyclone Gita caused widespread flooding and damage. The warm seas may have contributed to its strength.
Marine heat waves are becoming more common, Noll said. One was declared two years ago, in the summer of 2018/19.
The most severe was the 2017/18 season, when the oceans were up to 7 ° C warmer than average. “There were ocean temperatures as warm as 25 ° C, which was way above the norm. That’s what powered New Zealand’s warmest month on record, January 2018. “
This year’s sea surface temperatures are not expected to peak until January or February, Noll said, although we may not see these extremes. “We are still paddling in a very warm direction … If the marine heat wave conditions persist and expand over the course of a month or two, we could be preparing for a very warm start to the year 2021.”
A marine heat wave is unpleasant news for wildlife, whether at sea or in the mountains.
Northland’s marine species may be some of the first in the world to experience extreme temperatures on an average day. As the seas warm, fish and aquatic mammals will have to adapt to the heat, in addition to changes in the food chain, ocean currents and acidity.
Marine heat waves can also push hot air to mountain tops, with dire consequences for our glaciers, ice, and alpine species.
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