Weather: Heavy rain, gale-force winds hit New Zealand as parts of country brace for wet and wild week

The weather appears to have missed the memo that it's summer as heavy rain and strong winds are forecasted to lash parts of the country this week.

Unfortunately for holidaymakers, the wet and wild weather has forced many campers to cut their trips short, with a subtropical low set to bring heavy rain and gale-force winds for parts of Northland and the Tasman District.

MetService has issued a heavy rain warning from 1am on Wednesday until 5am on Thursday for the Northland region, with up to 160mm of rainfall expected. A heavy rain watch has also been put in place for 24 hours from 9am on Wednesday for the Auckland region, with the forecaster additionally issuing a 24-hour heavy rain watch for the Coromandel from 9pm.

"The Coromandel, western Bay of Plenty and Tasman regions have been upgraded to Heavy Rain Warnings. Auckland has been upgraded to a Strong Wind Warning," MetService later tweeted.

And festival-goers have also been impacted by the unseasonal shift in weather, with Summer Haze organisers cancelling the Matakana gig on Tuesday due to the conditions. 

In a post shared on the concert's official Instagram, the event organisers said: "We regret to inform you that the Summer Haze Matakana concert for Wednesday, 4th January 2023, has been cancelled due to the current and incoming weather forecast."

The organisers added the health and safety of the crew and those attending was their top priority.

According to MetService, the subtropical low over the Tasman Sea is expected to direct a strong and moist northeast flow to central and northern parts of the country.

In WeatherWatch's forecast for Wednesday, they said the northeasterly airflow will be responsible for the significant rainfall in Northland.

"Northeasterly winds strengthen during the day with strong to gale northeasterlies likely for areas north of Waikato. Northland has heavy rain, reaching Auckland this afternoon, especially in the east. Wairarapa should stay mainly dry. Out west (south of Taranaki) expect partly cloudy skies, light winds tend onshore in the afternoon," the forecaster said.

The forecast for the South Island is looking a little more promising however, with a sunny Christchurch expected to reach a high of 23C. Dunedin is also in for a warm day, with a high of 22C.

The West Coast could see the odd shower in the south near Greymouth.

"Cloud may thicken up later today about Southland and Otago. Winds generally from the northerly quarter, [with] afternoon sea breezes for Southland. Northeasterly winds become gusty [and] strong today about the coast north of Banks Peninsula."

A Newshub reporter who was driving over the Auckland Harbour Bridge said the speed limit has dropped to 70km/h because of the strong winds.

On Wednesday, New Zealand Transport Agency Waka Kotahi urged motorists to take care on the roads after MetService issued heavy rain warnings for the Tasman region.

"A heavy rain warning is in place for Tasman, northwest of Motueka, for 30 hours from midnight Wednesday with 120-180 mm of rain forecast. This will affect State Highway 60 in Tākaka/Golden Bay," Waka Kotahi said in a statement on Wednesday.

Waka Kotahi also said a heavy rain watch has been put in place in the Nelson/Marlborough region, which could impact motorists.

"A heavy rain watch is in place for the Richmond and Bryant Ranges, the Rai Valley, and the Marlborough Sounds from 6am on Thursday," Waka Kotahi said. "This covers State Highway 6 between Nelson and Havelock."