Large areas of the South Island and Wellington are in for heavy rain, snow and high winds for the rest of the week, MetService says.
Today's weather was a prelude, with a cold front moving across the North Island followed by a southwesterly flow that was expected to bring showers to most areas, with a moderate risk of thunderstorms from Whanganui to South Auckland.
Heavy rain and thunderstorms are possible from Waikato to Wellington and the Wairarapa, today before becoming fine later. Auckland could expect showers to become heavier later today, with strong southwesterlies.
A northwesterly system would follow the southwesterly flow, arriving in the capital tomorrow with rain and gusts up to 100kmh, MetService said, but the chance of forecast hail was now low.
However, forecaster John Law said "we have still got some pretty awful-looking weather" on the way.
In the South Island, a severe weather warning was in place for a front expected to approach the lower part of the country tonight and move northtomorrow.
A strong northwest flow preceding the front was expected to bring rain to the West Coast, and northwesterly gales about Southland, Otago and inland Canterbury, with wind gusts of 120kmh from this evening, and 140kmh gusts possible about Stewart Island and Foveaux Strait tomorrow morning.
Severe gales had the potential to damage trees and powerlines and create difficult driving conditions, especially for high-sided vehicles and motorcycles, MetService said.
From midnight until 3pm tomorrow, 80 millimetres to 100mm of rain was expected in the Westland Ranges south of about Otira, which was likely to cause rivers to rise rapidly and cause slips in vulnerable areas.
A cold southwest change was expected to follow the front, with snow expected to low levels in Fiordland and Southland.
More than 25 centimetres of snow are expected above 200 metres in 24 hours from tomorrow evening until Friday afternoon.
A weather watch was also out for severe thunderstorms early tomorrow morning across southern Fiordland, Southland and Clutha, especially about Foveaux Strait, MetService said.
These could produce damaging wind gusts in excess of 110kmh, as well as heavy rain and hail.
Further thunderstorms were likely through the afternoon and evening.