A big low will grow over the next 48 hours to engulf much of the Tasman Sea,tapping into sub-tropical air just north of New Zealand and helping to fuel more heavy rain on Wednesday as the system slowly crosses the country.

By Thursday a windy south to south west flow will spread northwards across most of the country and by Friday all of New Zealand will be cooler – with the worst of the polar blast mainly out to the east of the South Island.

A big high is coming afterwards – the weekend coming up should see conditions ease and calm down again.

There’s currently quite a strong pattern of large highs and deep lows tracking in from the west – but despite these large highs the rain events have made May wetter than average so far in most parts of the country. 

WeatherWatch.co.nz