Weather: Heavy rain watch for Fiordland and Southland as tropical low develops north of New Zealand

Heavy rain drenching the lower South Island could approach warning criteria today as forecasters monitor a developing tropical low that could bring unsettled weather to the upper North Island.

A heavy rain watch has been issued by MetService as a front is expected to bring a period of heavy rain to Fiordland and Southland today.

MetService meteorologist Katie Lyons said places such as Invercargill were already seeing rain as the system moved across the region.

“A heavy rain watch is in place for Southland from 9am today through to 7pm tonight,” Lyons said.

“We also have a heavy rain watch out for Fiordland from 9am today through 9pm tonight.”

There is a low chance the Fiordland watch will be upgraded to a warning, while the Southland watch has a moderate chance of being escalated if rainfall intensifies.

Lyons said the watches were updated this morning and are expected to remain at watch level for now while MetService continues to monitor rainfall totals.

She said MetService remained in contact with local councils in case conditions worsen.

Forecasters are also keeping a close eye on a developing weather system that could affect Northland early next week.

Lyons said the developing tropical low could move towards the country, but that it was too early to know its path and strength.

“From what we see at the moment on Tuesday into Wednesday, it does look like this low moves down and either brushes the top of the North Island or just kind of gets down a bit more to Auckland and Bay of Plenty as well,” she said.

Lyons said what MetService “can be a bit more certain of is the window that we’re looking at for where this low could impact us” would be late Tuesday through Thursday.

“It’s a bit too early and a bit too unclear for us to be confident to put out any watches, so we’re just keeping an eye on it at the moment.”

MetService said the system is expected to sit north of the North Island if it develops as forecast.