The top of the North Island is under a severe thunderstorm watch, with lightning and downpours tipped to rattle Auckland this evening as regions farther south grapple with snowstorms and heavy rain. 

MetService issued a new weather alert for Northland, Auckland, Coromandel and the Bay of Plenty this morning, active for eight hours from 8pm today. Flash flooding, landslides, and dangerous driving conditions are possible, the forecaster warned. 

Gusts up to 110km/h are also possible in these regions, as well as in Gisborne and Rotorua. These winds could down powerlines, trees and any loose structures. 

Civil Defence groups, including Auckland Emergency Management and the Bay of Plenty CD, have already warned residents to take precautions and keep an eye on the developing forecasts. 

Intense downpours have begun hitting the south of the country with snowstorms expected later, and heavy falls are slated for the North Island this afternoon. 

MetService has updated and extended its severe weather alerts, now covering North Otago, Dunedin, Clutha and Southland as well as the West Coast and the upper North Island. 

The Coromandel, Bay of Plenty, northern Gisborne and Northland are also under alert. MetService said there was a high chance the heavy rain watches would be upgraded to warnings. The weather watch for storm-battered Gisborne was upgraded to a heavy rain warning about midmorning. 

Heavy falls are expected in Auckland this afternoon. The daily high should reach 19C today and remain at 18C until the weekend, with rain forecast into next week. 

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. 

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

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

A 24-hour orange heavy rain warning came into effect for the Westland District at 11pm last night. Meanwhile, warnings will also come into force for Tasman northwest of Motueka, Richmond and Bryant ranges including the Rai Valley, and Mount Taranaki throughout Wednesday. 

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 urged people to clear drains and gutters in preparation. 

‘A lot of anxiety’ as wet weather disrupts farmers 

Federated Farmers Southland provincial president Jason Herrick said the upcoming conditions were expected to be very challenging for many farmers, more so off the back of a very wet September. 

“There’s a lot of stress and a lot of anxiety – she’s pretty hard graft but it is what it is. You take it as it comes. There is light at the end of the tunnel.” 

Throughout September, parts of Southland had more than 200mm of rain, Herrick said. 

“It is terrible timing. It’s the springtime when we’re doing all the lambing and calving and so it can be a challenging time of year anyway, and to just throw the weather on top of it.” 

A swathe of heavy rain watches have also been issued from Northland down to Bay of Plenty, with moderate-to-high chances they would be upgraded to warnings. 

Ferris said the potentially severe weather is brought about by a low-pressure system approaching from the Tasman Sea, which drags some warm and humid air across New Zealand’s shores. 

“While this does mean some warmer than average temperatures it also increases the chance of heavy rain as the system passes over.” 

Road snowfall warnings are in place from 9am today at the earliest for Crown Range Rd, Milord Rd (State Highway 94), 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.