“Frequent patterns of high pressure near and south of New Zealand during November, owing to La Niña, have caused more sub-tropical, northeasterly winds than normal. Reduced wind speeds through the month have prevented colder, subsurface ocean waters from getting churned up to the surface. In addition, sunshine has generally been above normal, which has helped to heat the ocean surface.”
Marine heatwaves are becoming increasingly frequent in a warmer climate with 963 marine heatwave days observed in the New Zealand region between 2010-2019 compared with 366 between 2000-2009.
“NIWA’s Seasonal Climate Outlook for summer will be released tomorrow, providing commentary on the likelihood of warm seas continuing through the season and their impact on the summer ahead.”