Strong blustery winds, squally thunderstorms and downpours are set to hammer central New Zealand and the upper North Island, including Auckland.
A strong wind warning has been put in place for Auckland including Great Barrier Island, Marlborough Sounds and Wellington with the southerly gales in the capital this afternoon expected to reach 120km/h.
Squally thunderstorms are expected across Northland, Auckland and Coromandel Peninsula this morning.
The average wind speed in Auckland had already hit 28km/h and was expected to climb to 36km/h by 10am, according to the Metservice. The rain was also expected to hit Auckland by 10am and continue through until at least 4pm.
Auckland Transport has warned commuters that the weather would cause delays and disruptions to ferry services throughout the day and into the evening.
The organisation also warned those cycling and walking to take care and watch out for debris with strong gales and heavy rain expected.
The poor weather caused a short delay to this morning's Great Barrier Air flight to the island. The first flight of the day was delayed by 15 minutes due to bad weather on the island, the airline confirmed.
No flights to or from Auckland Airport had currently been delayed due to poor weather, an airport spokeswoman said.
According to MetService, these thunderstorms may bring heavy rain of 10-25mm, and strong wind gusts of 90-110km/h, along with a low risk of localised downpours of 25-40mm.
"However there is moderate risk that some of the thunderstorms may become severe, bring localised damaging gusts greater than 110 km/h and localised tornadoes, especially to northern and eastern areas."
Wind gusts of this strength can batter trees and power lines, and may make driving hazardous.
According to MetService, if any tornadoes do occur, they will be localised.
The extreme weather is thanks to a deepening low pressure system that will track quickly from the Tasman Sea across the North Island.
This intense pressure system is expected to bring brief spells of heavy rain to many parts of the North Island and the top of the South Island.
There is a heavy rain watch in place for Northland this morning, as well as for Auckland, Great Barrier Island, Coromandel Peninsula, Waikato, northwest Nelson and Bay of Plenty throughout most of the day.
Further south a heavy snow warning is in place in Marlborough where rain may turn to snow down to 500m.
Forecaster Weatherwatch.co.nz is warning of huge waves on the west coast of the country from Thursday.
The forecaster predicts waves over Thursday, Friday and Saturday could exceed 10m.
Main centre forecasts today
Morning rain then a few showers. Possible squally thunderstorms until evening. Strong northerly turning strong southwest evening. High 19C, low 10C
Rain turning to showers afternoon. Possible squally thunderstorms and downpours. Strong northerly turning strong southwest evening. High 18C, 10C
Rain, some heavy from late morning with possible thunderstorms, easing to showers evening. Northerlies changing southwesterly evening. High 16C, 5C
Rain, heavy from late morning with chance thunderstorm and downpours, turning to showers evening as strong northerlies change strong westerly. High 18C, 7C
Showers turning to rain this morning, chance heavy from midday, easing to isolated showers evening. Gale southerly from afternoon gusting 120 km/h. High 12C, 5C
A foggy and frosty start then cloud developing. Southerlies developing in the morning. High 9C, -3C
Fine, but chance shower until evening. Southwesterlies. High 8C, 4C