Weather: Heavy rain, strong winds and plunging temperatures

MetService is urging people to make the most of any good weather today, as heavy rain and strong winds are forecast for many parts of the country from tomorrow.

The forecaster has issued orange heavy rain warnings, rain watches, strong wind watches and heavy snow watches for various parts of New Zealand.

MetService meteorologist Surprise Mhlongo told 1News a deep flow was expected to pass across the country late Wednesday into Thursday.

He said the week so far had brought "relatively quiet weather, especially in the eastern areas", and this was set to change to more unsettled weather.

"You can expect significant changes in weather and of the rainfall amounts we're expecting," he said.

Mhlongo said high lying areas would likely receive the most rain, saying Taranaki maunga was expected to get 180mm – 220mm of rain from Wednesday morning.

He said while there were "still a fair amount of uncertainties in the models at this point", wet weather was forecast throughout the country.

"It's most likely that everyone is going to get rain, at this point it looks like the main amounts will be over the highline areas with significant drop in temperatures for the South Island, and that's where we will see snowfall."

Heavy rain warnings have been issued for Bay of Plenty east of Whakatāne and inland Gisborne/Tairāwhiti, Tongariro National Park, Taranaki Maunga, the Tararua Range, Tasman District west of Motueka and Marlborough Ranges.

Heavy rain watches have been issued for Northland, Auckland, Buller, Grey, Westland and Fiordland.

In Canterbury, where a heavy snow watch had been issued, MetService said there was a high chance of this being upgraded to a warning as heavy snow above 300 metres was possible, especially about the Mackenzie Country.

"Travel disruption and damage to trees and powerlines possible. Cold conditions may cause stress for livestock," it said.

MetService warned people that streams and rivers may rise rapidly, and surface flooding, slips, and difficult driving conditions were possible.

"Clear your drains and gutters to prepare for heavy rain. Avoid low-lying areas and drive cautiously," it said.

Another MetService meteorologist John Law said temperatures were expected to tumble later in the week, with daytime highs struggling to get beyond the teens in much of the country.

"The second half of the week will be feeling very different to the first, as cold southwesterly winds sweep across New Zealand,” said Law.

“The coldest spots will be found in Central Otago, where daytime temperatures for Wānaka and Alexandra are only likely to reach 3°C or 4°C this weekend.”

Heavy Rain Warning - Orange

Bay of Plenty east of Whakatāne and inland Gisborne/Tairawhiti - 10 hours from 8pm tomorrow.

Tongariro National Park - 14 hours from 10am tomorrow.

Taranaki Maunga - 12 hours from 7am tomorrow.

Tasman District west of Motueka - 16 hours from 6am tomorrow.

The Tararua Range - 12 hours from 11am tomorrow.

Marlborough about and northwest of the Richmond Range, and Nelson east of Nelson City - 15 hours from 9am tomorrow.

Heavy Rain Watch

Northland and Auckland, including Great Barrier Island - 8 hours from 4pm tomorrow.

Buller, Grey and Westland Districts between Karamea and Harihari - 17 hours from 1pm tomorrow.

Fiordland north of Breaksea Sound - 13 hours from 9pm.

Heavy Snow Watch

Canterbury (excluding Banks Peninsula) - 12 hours from midnight tomorrow.

Strong Wind Watch

Northland and Auckland, including Great Barrier Island - 16 hours from 8am tomorrow.

Bay of Plenty east of Whakatāne and Gisborne/Tairawhiti - 12 hours from 9pm tomorrow.

Taranaki - 11hrs from 9am tomorrow.

Wellington and Wairarapa, including the Tararua District - 9 hours from 4am Thursday.