Forecasters are predicting 989mm to fall in a 62-hour constant deluge that will last until Thursday evening as the forecast worsens for the West Coast.

MetService forecasters are predicting a deluge of one to two times the region’s monthly rainfall over the space of a few days.

Arrangements are underway to activate an Emergency Operation Centre (EOC) as required from tomorrow morning in Westland due to the severe weather.

Emergency services and other key agencies such as infrastructure entities, representatives from the farming community, Department of Conservation and regional and local councils on Tuesday morning to share their updates.

Queenstown Airport has advised of multiple flight delays to the severe weather.

Several agencies are deploying additional resources into the area, including support personnel for South Westland.

”There is a considerable amount of caution and concern regarding this weather event. We cannot be complacent. MetService has kept the warning level at Orange, however with the amount of rainfall forecast we must remain prepared,” said West Coast Emergency Management group manager Claire Brown.

“There are a number of events and activities around the coast at this time. We are asking everyone to keep up to date on the road conditions and to be careful travelling as the worst of the weather passes by in the next three days.”

Accumulations around the ranges are expected to range from 600 to 800mm, and 200 to 300mm along the coast.

Peak downfall rates of 25 to 35 mm/h are expected, with such conditions posing risks of rapidly rising streams, rivers, surface flooding, and potential slips, rendering driving conditions hazardous.

The weather front is set to traverse northwards over Fiordland from Tuesday, and is anticipated to linger between Westland and Fiordland through Wednesday and into early Thursday.

Meanwhile, Fiordland and north of George Sound are also bracing for heavy downpours, with an additional 80 to 110mm and peak rainfall rates of 15 to 25mm/h anticipated.

The Canterbury High Country and the headwaters of Canterbury Lakes and Rivers south of Arthur’s Pass are expecting 400 to 600mm of rainfall around the main divide and 200 to 300mm further east.

Similar conditions are forecasted for the headwaters of the Otago Lakes and Rivers, with peak rates of 15 to 25mm/h.

Residents in these areas have been advised to prepare for the possibility of flooding and to exercise caution.

West Coast Emergency Management (WCEM) said it has started planning and preparing for the weather warning issued by MetService on Monday.

“WCEM asks everyone to keep up to date with the forecast and take precautions. This is a good time to review your emergency plans for home or work, and if travelling to check you have some emergency supplies [water, food, warm clothing] with you.”

Westland Mayor Helen Lash said important conversations are happening between herself and supporting agencies such as Fenz, St John, police, and NZTA Waka Kotahi.

“Everyone knows what is potentially coming, so we will wait for the latest update, and then start mapping things out from there. That may include placing certain people in certain areas.”

Wet end to the week for North Island

MetService meteorologist John Law said, for the next couple of days, the weather in the North Island is forecast to look good.

However, by Thursday, it will start to turn as bad weather will roll in from the west.

“For places like Northland and Auckland, we could see some strong winds and reaching gales at times,” he said.

He said southern Taranaki, Wanganui and Wellington could see similar conditions.

Law said the rain and wind is set to continue to move east on Friday.

“Places like the Bay of Plenty, Waikato and Auckland could well find some heavier rainfall,” he said.

“It’s a situation to be aware of, but it’s looking like there will be some heavy rainfall by Thursday and Friday.”

This article was originally published on the NZ Herald here.