State Highway 1 at Dome Valley is closed to southbound traffic due to a slip and Auckland Emergency Management are warning restrictions could be placed on the Harbour Bridge if wind gusts worsen.

The sub-tropical storm has begun dropping heavy downpours on Northland while Auckland and the Coromandel are bracing for a month’s worth of rain in just two days.

Metservice said this afternoon that Kaikohe had been hardest-hit so far today, with 96mm of rain falling by 2pm.

The heavy rain was moving south to Coromandel and Bay of Plenty, Metservice said, and lesser amounts of rain were expected in Auckland.

Auckland Emergency Management (AEM) duty controller Rachel Kelleher said, given there may be some increasing wind gusts throughout the afternoon and tonight, it was important to take “extreme care” while driving.

Kelleher warned there may be restrictions to the Harbour Bridge if wind gusts “get up” and said it was “really important” for people to keep an eye out on the weather forecast.

“Not just for today and tomorrow, but also as we move throughout this week because it does look like we might have some further adverse weather coming through around Wednesday and Thursday with the potential of thunderstorms.”

Kelleher said people should have their phones charged up, torches handy, water bottles filled and a plan if you need need to leave your home.

 “We are prepared to stand up civil defence shelters and civil defence centres if they are indeed needed and the locations of any of those sites will be made available throughout Auckland Emergency Management channels.”

This comes as NIWA modelling shows North Island rivers will “respond rapidly” to the heavy rain as the storm moves across the country and Civil Defence says both Top Energy NZ and Northpower are reporting some unplanned outages.

An orange heavy rain warning will come into force for Bay of Plenty, west of Kawerau and including Rotorua, from 2pm today and will remain in place until 2am Tuesday.

MetService is warning the area to expect up to 220mm of rain and peak rainfall amounts to reach 25mm/h.

There is also an orange heavy rain warning for Tasman northwest of Motueka from 3pm tomorrow through to 3pm Tuesday.

The wet and wild active front has been edging its way down the upper North Island and has forecasters warning of potential flooding and slips.

MetService meteorologist Mmathapelo Makgabutlane said rainfall so far has been widespread.

“We are still expecting that to continue for today,” she said.

“The other thing to keep in mind today is we are expecting quite strong winds as well.”

MetService said it’s been a windy 12 hours in Northland with Whangārei and Kaitaia recording 76km/h gusts.

Further north, Purerua has seen wind gust speeds around 87km/h and Kaikohe has seen speeds of 72km/h and 53mm of rainfall since midnight.

Northland’s heavy rain watch has been upgraded to an orange heavy warning.

It will be in force until 8pm tonight and MetService is warning that the area can expect to see up to 140mm of rain. Peak rates of rainfall will be around 15 to 25 mm/h, but are expected to increase to 25 to 35 mm/h in localised places late Sunday morning and afternoon.

“Further heavy rain is possible overnight Sunday and Monday morning.”

Overnight heavy downpours were recorded in Kaikohe, with 10mm of rain falling per hour.

Auckland is being warned to be ready for 26 hours of heavy rain from the early hours of today to tomorrow morning.

The National Institute of Water and Atmospheric Research (Niwa), meanwhile, says the low will cause an “atmospheric river” that will stick around for the week, “waxing and waning in intensity as it funnels moisture” from the tropics to New Zealand.

There are fears of a repeat of the deadly Auckland Anniversary weekend floods that saw the city’s leadership, including Auckland Mayor Wayne Brown, coming under fire for their response over the flooding’s first 12 hours, when much of the damage was done.

Seeing the increasingly bleak storm outlooks, Brown requested a top-level briefing with key emergency management staff on Friday.

Last night , MetService forecaster Aidan Pyselman said the “nasty weather” would peak today and tomorrow.

Auckland Emergency Management (AEM) has told Aucklanders to “keep an eye on forecasts” and prepare for bad weather, while MetService has issued a heavy rain watch for the nation’s biggest city.

Forecasters have warned of periods of heavy rain that “may approach warning criteria”.

An orange heavy rain warning has already been issued for the Coromandel Peninsula, with the region being told to expect between 150 millimetres and 200mm of rain from early Sunday morning to late Monday, with peak rates of 15mm/h to 25mm/h expected from Sunday evening.

It could mean the region will get a typical April amount of rain in less than 48 hours.

The Bay of Plenty, especially regions west of Kawerau, including Rotorua, should also expect heavy downpours from Sunday evening through to Tuesday morning.

AEM general manager Paul Amaral urged residents to monitor weather updates and make sure they’ve got a plan “in case the worst happens.

“We’re expecting high winds and rain for some areas of Auckland, so remember, in a storm, consider your travel plans carefully, never drive through floodwaters and phone 111 if your life is in danger,” Amaral said.

“Based on the latest advice from MetService, we are expecting areas on Auckland’s east coast, including Whangaparāoa and Aotea Great Barrier, to be hit with the most intense rainfall and wind.

“Charge your phones, ensure you have a torch ready and check your emergency plan.”

MetService’s Pyselman says there will be little relief from the wet as the week goes on too, with more heavy rain potentially coming on Thursday and Friday.

But while it will be wet, the moist air of the sub-tropical storm will also bring mild autumn temperatures.

“This coming week is looking really warm, especially with overnight temperatures in the mid-teens for a lot of the country,” Pyselman said.

There is also a strong wind watch in place for Northland, Auckland, the Coromandel Peninsula and eastern Waikato near the Coromandel and Kaimai ranges.

Waka Kotahi New Zealand Transport Agency advised any drivers around the Coromandel Peninsula this morning to be cautious.

“Many locations on the Coromandel network are still compromised following this year’s storm events, and drivers need to be aware that heavy rain will increase the vulnerability,” said Waikato journey manager Liam Ryan.

A damning review into the record-breaking Auckland Anniversary weekend downpour, which was undertaken by former police commissioner Mike Bush, found that “senior leaders underestimated the importance of their visible leadership roles”.

Wayne Brown was widely criticised for the slowness of his public response to the event and the eventual decision to place the Auckland region under a state of emergency after 10pm, when flooding was already widespread across the city.