Downpours are expected to hit the country tomorrow, prompting MetService to upgrade and extend its severe weather alerts across the upper North Island and West Coast.

A heavy snow watch has been issued for Central Otago and Queenstown, along with four road snowfall warnings for mountain passes in the Southern Alps. The Coromandel, Bay of Plenty, northern Gisborne and Northland are also under alert for heavy rain.

While Auckland had a forecast of cloudy periods and isolated showers today, heavy falls are expected tomorrow afternoon. The daily high should reach 19C on Wednesday, and remain at 18C until the weekend, with rain forecast into next week.

MetService’s five-day rain forecast imagery shows a mass of rain from the Tasman Sea slamming into Fiordland early Wednesday and fully enveloping the country early Thursday morning.

MetService meteorologist Lewis Ferris said it was “a bad start for the first week of the school holidays”.

A smattering of orange heavy rain warnings are in place for 24 hours from 11pm today for the West Coast, Tasman northwest of Nelson, and the Richmond and Bryant Ranges including the Rai Valley in Nelson.

In the Bay of Plenty, it was possible more rain could fall there in 36 hours from Thursday than in all of its notably dry September.

Up to 190mm of rain is expected on the West Coast, threatening to cause streams and rivers to rise rapidly, surface flooding, slips and difficult driving conditions. MetService has urged people to clear drains and gutters in preparation.

Road snowfall warnings are in place from 11am tomorrow at the earliest for the Milord Rd (State Highway 94), Crown Range Rd, Lindis Pass (SH8) and Haast Pass (SH6). These should all lapse by 3am Thursday.

Snow is possible down to 500m in Otago and South Canterbury on Thursday, when a mass of cold air passes over the South Island. 

Ferris said: “On Thursday, as a low-pressure system gets close to our shores, it drags in some cold air from the south of the South Island, and that’s lining up with the band of rain that brings the risk of snow.” 

It comes as Niwa warns of a potential for more downpours throughout October, amid an emerging “La Nina-like” pressure pattern raising the odds of big rain events. 

Raphael Franks is an Auckland-based reporter who covers breaking news. He joined the Herald as a Te Rito cadet in 2022. 

Sign up to The Daily H, a free newsletter curated by our editors and delivered straight to your inbox every weekday.