Once again a large high pressure system is drifting past the country, well to our north. As it tracks eastwards the anticyclonic flow pushes air down from between Northland and New Caledonia across northern parts of New Zealand.  At the same time a low in the Tasman Sea is tracking towards New Zealand, but it’s further south and has cyclonic winds – this feeds into that same wind flow over the North Island in particular, creating warm nor’westers across Wednesday.

Northland may reach 20 degrees while Auckland, Waikato, Bay of Plenty, Hawkes Bay and Gisborne may all reach the late teens.

The windy warm nor’wester will also affect northern parts of the South Island, with Kaikoura likely to also reach into the late teens.

But then the southerlies arrive.

So Northland tumbles from Wednesday’s high of around 20 degrees, to highs of 12 degrees over the weekend and next Monday.

Auckland tumbles from a high on Wednesday in the late teens, to highs as low as 11 or 12 this weekend and early next week.

In Hawkes Bay highs in the late teens on Wednesday will tumble into the single digits next week.

Wellington looks to have single digit highs from Friday to Monday – and surrounding days only getting to 10, after a high of around 13 or 14 on Wednesday.

Hokitika on the West Coast has a high of 11 on Wednesday and Thursday but then just 8 or 9 into Friday and Saturday. The south east wind flow, as usual, means the West Coast will be one of the sunniest places in New Zealand by the weekend with potentially sunny skies for several days after (frosty nights too!).

Dunedin has a high of just 8 on Wednesday – but the high is only 5 on Saturday, while Queenstown goes from a balmy high of 4 degrees on Wednesday, to a ‘high’ of 1 degree on Friday and just 2 over the weekend.

Meanwhile, Saturday morning is likely to see severe frosts through the South Island’s interior with overnight lows below -10C expected.

– Image / A large high north of NZ is feeding down warm air to some parts of the country, while a low in the Tasman Sea pushes windy, mild, nor’westers from the Tasman area. The polar southerlies are on the left hand side pushing into Sydney and eastern Australia.

– WeatherWatch.co.nz