The MetService rain map for 2pm on Friday. Photo: Screenshot / MetService
Heavy rain is forecast for the top of the North Island, Bay of Plenty and Tasman on Thursday and Friday.
Meteorologist John Law said wet weather would head towards parts of Southland and Fiordland overnight Wednesday with some heavy falls expected in places like Westland and the far western side of the Tasman District on Thursday.
Heading into Friday, the wet weather will move towards parts of the North Island as well, he said.
"As we head through the [Thursday] morning and into the afternoon, we'll find that rainfall feeds on towards parts of Northland with some heavy falls through there and perhaps even the odd rumble of thunder."
On Thursday night the rainfall will move down to places like Auckland the Coromandel and parts of Taranaki, he said.
Generally it will be dry and clear on the eastern side of the North Island on Thursday, he said.
In the South Island, heavy rain is forecast for parts of Southland and Otago on Thursday, with patchy rain forecast for parts of Canterbury.
"The heaviest rainfall [will be] up about the ranges and also ... western parts of the Tasman District."
Friday may see heavy rainfall in places like Nelson and Marlborough which may see severe weather warnings issued for those regions, he said.
MetService has issued heavy rain watches for the following regions:
- Northland from 1pm Thursday until 11am Friday
- Auckland including Great Barrier Island and Coromandel Peninsula from 8pm Thursday until 4pm Friday
- Bay of Plenty and Rotorua from 10pm Thursday until 8pm Friday
- Mt Taranaki from 10pm Thursday until 6pm Friday
- Tasman northwest of Motueka from 6pm Thursday until 6pm Friday
- Fiordland north of Doubtful Sound and the ranges of the Westland District from 11am Thursday until 3am Friday
Laws said on Wednesday the coldest temperatures were down south and it was -7C in Tekapo.
"A cold night coming up tonight but not quite as cold as those early morning temperatures we saw this morning."
Below zero overnight temperatures are forecast overnight Wednesday for Canterbury, but it will not be as cold as the -5C in Christchurch on Wednesday morning, he said.
Friday morning is not expected to be as cold as it has been in the North Island but it would be wetter and windier, he said.
Most early morning temperatures in the South Island were expected "to stay just this side of freezing" first thing Friday morning, he said.