Civil Defence is warning Aucklanders to “get a plan ready in case the worst happens” ahead of heavy rain warning expected to hit the region this weekend.

Auckland Emergency Management general manager Paul Amaral urged Aucklanders to “keep an eye on forecasts” and be prepared before the predicted bad weather strikes the upper North Island from early Sunday morning.

“If you live in an area prone to flooding or isolation, make sure you’ve got a plan to secure your property, shelter in place if you need to or know what you might need to do if evacuation is required,” Amaral said.

“Pre-storm checks include clearing gutters and drains on your property, securing loose items outdoors and checking your emergency plan is up to date.

“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 flood waters and phone 111 if your life is in danger.

“Based on the latest advice from MetService, we are expecting areas on Auckland’s east coast, including Whangaparaoa 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.”

Heavy rain and gales are bearing down on the North Island, with an atmospheric river set to unpack a torrid week of wet weather on Auckland and surrounding regions.

One forecaster predicts at least one month’s worth of rain - possibly more - could fall between Sunday to next Friday with up to 200mm predicted for parts of the top half of the North Island and the South Island’s West Coast.

Meanwhile, Auckland Mayor Wayne Brown is requesting a top-level briefing from key emergency management staff ahead of the tropically-fuelled storm.

A review into the fatal Auckland Anniversary weekend floods concluded the city’s leadership was found wanting after the lack of early response.

Brown, who apologised for “dropping the ball” in his public communication the night of January 27, has today sought expert advice in advance of the storm hitting.

“The mayor has requested a briefing from emergency management staff. At this stage we have no further information,” said a spokesperson.

Meanwhile, Brown today said Auckland Emergency Management staff have presented a detailed work programme for implementing the recommendations of the Bush review into the January 27 floods.

There was a strong focus on improving operational and governance relationships and a key recommendation to complete a review of a group plan with urgency would see a draft of the plan coming to the civil defence and emergency committee for consultation in July, he said.

Auckland Mayor Wayne Brown speaks at an Auckland Emergency Management (AEM) press conference. Photo / Jed Bradley

The rain is forecast to start falling on Saturday evening across Northland before the system moves to Auckland, Coromandel and Bay of Plenty on Sunday.

Auckland will get eight days of wet weather from Sunday, the first few days with heavy downpours and gales forecast.

The first weather alerts were issued by MetService this morning.

A 42-hour heavy rain watch is in place for Northland from 9pm tomorrow, and Auckland’s rain is set to start before dawn on Sunday.

A strong wind watch has also been issued for Auckland and Northland across the weekend through to Monday afternoon.

The wind is expected to whip up wild seas with waves up to 6m crashing against the upper North Island eastern coastline on Monday night.

MetService forecaster Jessie Owen said the sub-tropical low-pressure system packed with strong winds and rain was bearing down on New Zealand dragging a lot of warm wet air with it.

“It’s going to bring rain to the most northern parts of the North Island such as Northland late on Saturday and then spread south throughout the weekend.”

Owen said some of the rain would be heavy. It would also be partnered with strong northeasterly winds that would whip up wild seas.

Weatherwatch.co.nz this morning warned the gales had potential to be damaging, gusting up to 90km/h in exposed parts.

“This is enough to cause isolated power cuts and trees/branches down,” said forecaster Philip Duncan.

Owen said next week the low would keep tracking south dragging the rain across most of the country, unleashing the worst weather on northern and western regions.

“After that low moves to the south [and] we’re into a general wet disturbed northerly flow.

“We’re looking at several bands of rain coming in from the north. It’s all looking a bit messy and not particularly well defined but wet.”

Auckland, Northland, Coromandel and the Bay of Plenty were expected to fare the worst.

“We don’t have any warnings out just yet but we probably will within the next day or so,” she said.

The same regions would also be at risk of strong winds and big swells.

Owen said after a few chilly nights people would see a return to sticky, humid conditions.

Auckland day-time temperatures are forecast to remain above 20C for the coming week even as the tropically charged wet spell swamps the atmosphere.

“Once this warmer air comes down we’re looking at some pretty warm overnight temperatures in the mid-to-high teens.

“There’s not going to be much cooling between day and night from Saturday night in the Far North.”

Niwa said the atmospheric river would import water vapour from the tropics - or fuel for rain - increasing the risk of heavy downpours.

“Since the low originates from the subtropics, it will drag warm, moist subtropical air over New Zealand, raising overnight temperatures into the teens for most of the North Island.”

Weatherwatch said the high levels of moisture and warmth from the tropics could produce thunderstorms. The main risk would be from Wednesday to Friday next week.