UPDATED 

Torrential rain continues to affect the Coromandel Peninsula and western Bay of Plenty with reports of minor flooding now coming in.

MetService has today increased their rain warnings to 18.  Click here to view them all.

Civil Defence authorities are on standby around New Zealand as they prepare for severe weather.

In Canterbury, the rain has started to fall with up to 250 millimetres predicted over the next few days. Strong gales and snow down to 500 metres are also in the mix.

WeatherWatch.co.nz weather analyst Richard Green says while there is patchy rain around Christchurch, it is falling heavily in the western suburbs and out towards the airport. There is surface flooding on Memorial and Roydvale Avenue.

Mr Green says the rain is forecast to get heavier this afternoon, with the heaviest falls tonight and tomorrow morning.

Emergency Management Office Emergency Manager Jon Mitchell says staff are monitoring the situation closely. He says drivers are advised to take emergency supplies in their cars, including blankets, walking shoes, waterproof clothing, medicines and food and water.

The area hit hard by a storm which struck Nelson last weekend is again being closely monitored by Nelson Civil Defence. Many families in Tapawera were airlifted to safety after being trapped by floods.

And while the amount of rainfall expected is not likely to be very high, Civil Defence are nevertheless urging residents to remain vigilant because rivers and streams could still be blocked following last weekend’s storm.

MetService says at least 34 millimetres of rain fell overnight in the Bay of Plenty, and it is expecting at least 140 millimetres in the Western Bay area before midnight tonight.

Environment Bay of Plenty spokeswoman Linda Thompson says the rain is not causing any problems just yet. She says the council is urging farmers to move stock to higher ground.

Tauranga City Council staff are urging locals to clear drains and gutters to avoid flooding.

Meanwhile the main low, currently west of Nelson, will deepen even further today and grow in size.  This low will slowly move towards Taranaki over the next 24 hours and will bring heavy showers and thunderstorms to the North Island’s west coast tomorrow afternoon and evening, along with strong winds while at the same time feeding very heavy rain into the South Island’s east coast.

Auckland & Northland

“A band of heavy rain has already cleared Auckland” says head weather analyst Philip Duncan.  “As we said yesterday, this was never going to be an Auckland event at the beginning, it is for eastern parts of both islands up until Tuesday morning”.

But Mr Duncan says the sheer size of the still developing system means that while conditions may be easing in Auckland and Hamilton this morning, it’s far from over.  “We’ll see heavy showers developing during Tuesday for the upper North Island which may well have embedded thunderstorms and cause localised surface and even flash flooding.  On top of that the strong winds from the system won’t arrive until later tomorrow then last for days”.

Yet another low is now being predicted by WeatherWatch.co.nz to move in from the northern Tasman Sea on Thursday bringing further heavy rain to Auckland.

“The heavy rain that fell over Auckland early this morning has now stalled just east of the city, over the Coromandel Ranges.  If that had happened over Auckland instead there would’ve been significant flooding in Auckland today”. 

Mr Duncan said since yesterday the prediction by WeatherWatch and MetService was for this to happen.

However with a new low developing just off Northland’s coast some rain is still affecting eastern areas.

WeatherWatch.co.nz predicts cloudy skies for much of the day in Auckland and Northland and frequent showers. 

“For these two regions the rougher weather will likely be Tuesday afternoon, Tuesday evening and then again on Thursday”.

Coromandel, Bay of Plenty, Gisborne, East Cape

Heavy rain is continuing to be fed into the Coromandel Peninsula this morning, including both coasts from Thames to Whangamata. 

WeatherWatch.co.nz says the rain will linger for much of the day bringing slips and causing rivers to become swollen, possibly flooding some low lying areas. 

It’s possible the severe weather may affect some state highways, especially because of the risk of slips.

The heavy rain will slowly move across Bay of Plenty and East Cape today, bringing the same threat of rock falls and slips on the state highways.  Surface flooding is also highly likely, says WeatherWatch.co.nz.

South Island concerns

The low, which is expected to double in size today and then roughly double on itself yet again tomorrow is forecast to bring rain heavy enough to cause flooding in some regions, most likely across eastern parts of the South Island but also possibly in northern regions of the South Island.

Heavy rain is now being reported to WeatherWatch.co.nz in Ashburton and Christchurch.

This morning NewstalkZB is reporting severe flood warnings have been issued for all North Otago catchments on Monday night and into Tuesday.

The Otago Regional Council says 250 millimetres of rain is predicted, which is higher than any previously recorded level in North Otago.

Farmers are being advised to move stock and equipment from low-lying areas and the Regional Council says flooding could affect many roads, including State Highway One.

The Dunedin and Taieri catchments could also be affected.

At the time this story was written there was 16 rain warnings in force.  Click here to see all current warnings.

WeatherWatch.co.nz will have extensive updates over the following 72 hours.

– WeatherWatch.co.nz, additional NewstalkZB