Bay of Plenty is likely to be upgraded to a heavy rain warning tomorrow, MetService says.

A heavy rain watch remains in place for the region, including Rotorua, between 1pm tomorrow and 5am Saturday.

"A Heavy Rain Warning will be issued if there is an expectation that widespread rainfall (over an area of 1000 square kilometres or more) greater than 50mm will fall within 6 hours or 100mm within 24 hours," said MetService meteorologist Michael Pawley.

Periods of heavy rain were expected, which could cause surface flooding, slips and difficult driving conditions.

MetService said there was a high chance this would be upgraded to an orange warning.

An orange heavy rain warning has been issued for Coromandel Peninsula and Waikato between 11am tomorrow and 2am Saturday.

Severe Weather Update

Heavy rain and strong winds move in on Friday.

A lot of this rain will be falling on saturated soils so impacts will come about faster.

Rapidly rising rivers, surface flooding and potential slips.

Get all the details here: https://t.co/HZ2TSD5rV7 pic.twitter.com/eDNODngBBj

— MetService (@MetService) July 9, 2025

Pawley said a front over the Tasman Sea spreads on to New Zealand this week, bringing heavy rain to northern and western parts of the North and South Islands.

The forecast for Bay of Plenty today is mostly cloudy with isolated showers.

On Saturday, early rain clears to cloudy weather with a chance of a shower, while Sunday is mostly fine with possible showers.

It comes after two weeks of similar rain watches and warnings for the region, said Pawley acting like a “scoop” for wild weather.

Parts of Bay of Plenty received more than 100mm of rain in 24 hours last Thursday, with flooding reported.

"A Heavy Rain Warning will be issued if there is an expectation that widespread rainfall (over an area of 1000 square kilometres or more) greater than 50mm will fall within 6 hours or 100mm within 24 hours.

"Warnings are issued within 24 hours of the severe weather event, so I'd advise to keep an eye on our Warnings & Watches page, as the next updates will be this completed this evening and then again on Friday morning."