Weather: NIWA warns 'polar jet' to cause plunge in temperatures, rain, thunderstorms, wind to lash NZ

Weather: NIWA warns 'polar jet' to cause plunge in temperatures, rain, thunderstorms, wind to lash NZ
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With winter just around the corner, New Zealand is set to get hit by more wild weather, with wind, rain and thunderstorms to lash the country. 

MetService said low and associated fronts over the Tasman Sea are expected to move east and hit New Zealand from late Sunday to early Tuesday, bringing strong winds and heavy rain to many parts of the country. 

NIWA said a "sub-tropical jet" will keep New Zealand's weather story moist and mild but warns it won't stay like that for long.

"Just as the page turns to meteorological winter next Thursday, the polar jet will poke northward, plunging our temperatures in early June," NIWA said.  

Weather warnings and watches 

This has seen MetService issue 13 weather warnings and watches for parts of the South and North Islands. 

An orange heavy rain warning is in place for Tasman west of Motueka from 2am to 5pm on Monday, with 120mm of rain expected. 

Westland south of Otira is expected bare the brunt of the bad weather with a heavy rain warning in place for 37 hours from 5am on Monday until 6pm on Tuesday 

MetService said the area should expect 280mm of rain at peak rates of 25mm/h, with thunderstorms possible. 

Heavy rain is also coming for Northland, with a warning in place from 3pm on Sunday until 6am on Monday, with 80mm of rain expected. 

Bay of Plenty about and west of Whakatane including Rotorua is also in the firing line, with a heavy rain warning issued from 5am to 9pm on Monday. 

The Bay of Plenty east of Whakatane and Gisborne north of Tokomaru Bay doesn't escape the bad weather with a warning in place from 10am on Monday until 3am on Tuesday. 

The forecaster said this area should expect 140mm of rain at peak rates of 25mm/h, with thunderstorms possible. It also warns the warning may be extended. 

MetService warns the heavy rain in these areas under a heavy rain warning could cause streams and rivers to rise rapidly. 

"Surface flooding and slips are also possible and driving conditions may be hazardous," MetService said. 

A heavy rain watch is also in place for Mount Taranaki, Buller, Richmond and Bryant ranges including the Rai Valley, also Tasman from Motueka eastwards but excluding the Nelson Lakes, Fiordland, Auckland including Great Barrier Island and the Coromandel Peninsula. 

MetService warns these areas will see periods of heavy rain, with thunderstorms possible for Auckland, Great Barrier Island and the Coromandel Peninsula. 

The upper North Island will also be lashed by gale-force winds, with a strong wind watch in place for Northland and Auckland including Great Barrier Island from Sunday evening until Monday morning. 

"Northeast winds may approach severe gale in exposed places," MetService said. 

"Drivers need to be prepared" - NZTA's warning for South Island drivers 

The expected wild weather has seen Waka Kotahi New Zealand Transport Agency (NZTA) warn motorists at the top of the South Island to take care when on the roads over the next few days. 

Tasman and Nelson drivers will need to have their safe driving skills fully tuned with bad weather forecast for the region on Monday, NZTA said. 

The weather will affect State Highway 6 and State Highway 60 and heavy rain increases the risk of slips, rockfalls, and localised flooding on these routes," NZTA said.

Contractors will be monitoring the slip at Spooners Saddle on State Highway 6 ahead of further repairs planned for Wednesday.

"Drivers need to be prepared for driving hazards. For Nelson drivers, please take extra care on your commute to and from work," NZTA said.

"Some simple steps will help keep you and others safe on the roads. Use your headlights when visibility is poor, watch your speed and following distances, and drive to the conditions. You never know what might be around the next corner.

"It is also important to check road and weather conditions before you travel, as bad weather can see roads closed at short notice."