Temperatures will be up and down this week as subtropical and polar air swirls around us, but it’s the windy westerlies that will be the main feature of NZ’s weather with surges of gales, potentially severe gale, coming and going.

Around Wednesday high pressure does briefly track over the very upper North Island – and as it departs Thu/Fri it drags down subtropical winds for some, windy nor’westers out of Australia for others – either way, it’s warmer.

But this weekend a large low south of the country will bring yet another surge of windy westerlies, especially through the mountains/ranges and out to the east. Severe gales are possible in both main islands