Forecasters say the bullseye of the wettest weather is likely to shift, before snaking back and forth between islands into next week.
MetService issued warnings for the top of the South Island: An extremely large amount of rain could fall about Nelson-Tasman and Marlborough until this evening before the storm moves further south.
Upwards of 250mm of rain was forecast to fall about Nelson-Tasman and Marlborough over the next day to Saturday evening.
MetService updated its warnings yesterday morning, saying streams and rivers could rise rapidly, and any deluge could cause surface flooding, slips and would make driving dangerous.
Meanwhile, in Auckland, where wet weather hampered both the morning and evening commute yesterday, Saturday was set for cloudy periods and a few showers, MetService said.
Train services were cut in the morning due to a weather-related safety event and ferry services for Rakino Island wouldn’t run until the weather eased tomorrow.
Temperatures in the city were expected to sit at 22C with a low of 17C. MetService said the tropical air which was bringing the rain also made for unusually warm and humid conditions for May.
“Several spots across the motu have even had their warmest May temperatures on record. These include Auckland, Hamilton, Whanganui and Queenstown,” MetService said.
But with the muggy weather came torrential downpours for Northland and Taranaki.
Roads started flooding across Northland, particularly in the Far North yesterday, and access on more roads was restricted due to fallen trees, slips and washouts.
Two police officers kneeled in floodwaters to clear out a blocked drain by hand, successfully draining the inundation on one street.
As of 4pm yesterday, five roads in the Far North were closed due to flooding, all in the Doubtless Bay and wider Kaitāia areas.
MetService issued an orange heavy rain warning for Northland, where up to 100mm of rain was likely to fall over 21 hours from 9am yesterday to 6am today.
Up to 130mm was expected to fall around Mt Taranaki over 24 hours from yesterday morning until 9am today, where an orange heavy rain warning was also in place.
“These areas have seen a lot of rain recently. Further rain could cause significant impacts,” MetService meteorologist Andrew James said.
“Rain sticks around the through the weekend and into early next week, but snakes back and forth over western parts of both islands,” he said.
The National Institute of Water and Atmospheric Research (Niwa) said the atmospheric river, which has brought a waterfall of rain throughout this week, could clearly be seen in satellite images.