New Zealand set to be hammered by significant rainfall as front moves north

NZ Herald

24 Mar, 2019 02:48 AM4 mins to read

The active front is set to have its way over the South Island before moving northwards. Photo / Supplied

Severe weather is set to unleash itself on New Zealand over the coming days, starting in the deep south before sweeping northwards.

Forecasters are warning the big wet could trigger slips, flooding, road closures and detours.

The MetService predict heavy rain accumulation for parts of the South Island with Fiordland and West Coast set to take on 600mm between Sunday and Tuesday.

"A change is coming for many this week, as a cold front moves over the South Island and lower North Island," MetService meteorologist Rob Kerr said.

"Warm, moist northwesterlies ahead of the front set to bring heavy rain and gale force winds to southern and central parts of the country during the next few days."

Severe Weather Warnings are now in place as NW winds bring heavy rain to parts of the South Island over the next few days. Details at https://t.co/5g5AYiYBwb ^RK pic.twitter.com/MiF7Bd7k2y
— MetService (@MetService) March 23, 2019

Otago and Canterbury headwaters can also expect significant rainfall with 500mm possible about the divide and 280mm within 20km of the divide during tomorrow and Tuesday.

The cold front will slowly sweep over the South Island before stalling over the North Island about midweek.

In Auckland, weather consisting of cloudy periods and isolated showers can be expected before the front arrives and with it, rain and windy conditions.

"As [the front] stalls, it's going to bring more rain and shower activity across the North Island," MetService meteorologist Josh Griffin said.

"In Auckland ... there is some rain developing late Wednesday into Thursday and it'll kind of be cloudy and a bit showery for the Auckland area towards the end of the week."

This shows expected rainfall through Monday, and already amounts will be >150 mm in the Alps. By Wed, amounts >500 mm are possible in the Alps, and 200-300 mm possible in low elevations of the West Coast.

* Flooding is likely
* High winds & saturated ground may bring down trees. pic.twitter.com/dMfXA7vPll
— NIWA Weather (@NiwaWeather) March 24, 2019

However, the time has not yet come to pack away the shorts and t-shirts with New Zealand's long, hot summer set to linger.

Temperatures have remained consistently in the mid to high 20s for the upper North Island and in the low 20s for much of the rest of the country.

A high-pressure system brought settled weather to the country this month and despite the arrival of the cold front midweek, the weather will remain warm.

The continuing mostly settled, warm weather might be bringing smiles to many, but it was no anomaly.

"It seems to be nothing out of the ordinary for this time of year ... it's not going to be getting cold just yet," Griffin said.

WeatherWatch.co.nz says the combined rain bands will create a significant rain event with totals potentially exceeding 300 or 400mn in the next few days on the West Coast.

"While the West Coast, especially Fiordland and Westland, are used to big rainfall totals, the rain coming this week is above normal and could lead to slips, flooding and road closures and detours."

The heaviest rain would from around Hokitika southwards.

"It's unlikely much rain will fall over eastern areas like Canterbury, but some is possible especially closer to the ranges.

"For those needing rain in the North Island this front will weaken significantly as it moves northwards around late Wednesday and Thursday, but there may be some isolated downpours which bring relief."