Heavy rain set to hit NZ, Tasman faces fresh flood risks with 57-hour drenching forecast

Heavy rain watches are in force across the top of both islands – including flood-hit Tasman – bringing fresh slips and flood fears.

The weather is set to turn for the remainder of the school holidays, with heavy rain for northwest Tasman starting at 3pm today and lasting until midnight Friday.

MetService says this would be followed by bursts of “fast-moving” heavy rain for many areas on Friday.

The first front was expected to bring a period of heavy northerly rain for the already flood-devastated upper South Island from this afternoon until early tomorrow morning.

Another “more intense” front was forecast to move east across New Zealand on Friday, bringing heavy northerly rain and strong winds to many areas, MetService said.

MetService meteorologist Lewis Ferris told the Herald Friday is set to bring the worst of the heavy rain, which will continue to linger into Saturday.

“The bigger concern is as we head into Friday, that’s when we have quite a widespread band of heavy rain moving on to the country from the Tasman Sea, affecting northern and western areas.”

The heavy rain watches for the already saturated upper South Island are likely to be upgraded to a warning tomorrow morning, Ferris said.

“That means that potential for a bit of tree fall, some slips, [and] more surface flooding.

“It is a relatively quick burst of heavy rain. It’s not the situation that we saw at the end of June with that prolonged, persistent heavy rain.”

With the current state of the region, residents should pay attention to forecasts.

Auckland will receive a burst of heavy rain on Friday, with a showery weekend and slightly above-average morning temperatures.

Heavy rain watches are in force across much of New Zealand, with a band of rain expected to bring a “fast-moving” deluge. Photo / MetService

How likely are thunderstorms?

The chance of thunderstorms accompanying the heavy rain across the country cannot be ruled out at this stage, Ferris said.

There is a low risk of thunderstorms in northern Northland from late afternoon, spreading south to central Northland this evening and tonight.

A low risk of thunderstorms also develops along the west of the South Island this evening.

For southern Westland and Fiordland, the risk of thunderstorms increases to moderate during the evening.

These thunderstorms may bring localised heavy rain with intensities of 10 to 20mm per hour and small hail.

What is in store for the weekend?

Much of New Zealand won’t see clear skies for the final weekend of the school holidays after a prolonged period of unsettled weather.

“It just looks a little bit messy heading into the weekend.

“It’s looking better for people who are in the eastern areas of the North and South Islands, but really not a perfectly sunny weekend.

“We’re in a quite generally unsettled run of weather, which looks to linger as we move into next week.”

People who want to make outdoor weekend plans “shouldn’t assume the weather is going to be fine because it is going to be quite changeable in the coming days and through the weekend”, Ferris said.

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