Violent thunderstorms are to lash the country with torrential rain and flash flooding for the fifth day in a row.

MetService has issued a thunderstorm warning covering much of the country and severe electrical storms are in store for the upper half of the North Island.

The electrical storms as set to hit after lunch, rumbling across the island from south of Auckland to Taihape. Those caught under the thunderous clouds can expect intense downpours packed with hail.

People are being warned there could be flash flooding and slips and to expect driving conditions to become dangerous during the downpours.

Advertisement

The South Island is also due to be rocked by the late spring storms. MetService has issued a moderate risk of thunderstorms from Nelson to Central Otago also after lunch.

Yesterday's thunderstorms brought heavy localised deluges with large hail stones sparking flash floods and slips.

On Tuesday more than 10,000 lightning strikes were recorded over the country and severe thunderstorm cells sparked warnings for the Mackenzie Basin and Marlborough.

WeatherWatchnz.co.nz head weather analyst Philip Duncan said the daily thunderstorm pattern was more typical for the peak of summer, not spring. He explained that the thunderstorms occurred as easterly and westerly winds converged in the middle of the country. They typically start around lunch time, then peak from 3pm to 6pm in the North Island and 4pm to 7pm in the South Island because of their later sunset. The storms subside in the late evening.

"Then they'll pop back up again tomorrow morning like Groundhog Day.

"It's very unusual, this pattern. It's not normal in spring to have long spells of warmer than average calm weather. This is very much like the peak of summer.

"The word normal shouldn't be used. This isn't normal weather. I think it'll break quite a few records."

Duncan said some areas of the central plateau would see a month's worth of rain this week.

The thunderstorms will continue through until Saturday when a strong westerly takes over the country. The South Island will clear up on Saturday and the whole country will be clear on Sunday.

Fine weather would bring some relief next week except for a small sub-tropical low potentially brushing northern New Zealand, Duncan said.

But mid to late December looked more like spring when downpours and rain are expected from a front now traversing Australia.

The Ministry of Civil Defence and Emergency Management advises that as storms approach people should:

​•Take shelter, preferably indoors away from windows.
​•Avoid sheltering under trees, if outside.
​•Move cars under cover or away from trees.
​•Secure any loose objects around your property.
​•Check that drains and gutters are clear.
​•Be ready to slow down or stop if driving.

During and after the storm, beware of fallen trees and power lines, avoid streams and drains as you could be swept away in flash flooding.

Main centre forecasts

Whangarei

Mainly fine, but a few afternoon​/​evening showers. Light winds and a high of 23C.

Auckland
Sunny spells, chance shower. Light winds and sea breezes and a high of 23C.

Hamilton
Partly cloudy. Showers from late morning. Possible thunderstorm. Light winds and a high of 23C.

Tauranga
Partly cloudy. Showers, mainly from late morning. Chance thunderstorm. Light winds with a high of 21C.

Wellington
Morning low cloud or fog, then fine. Light winds and a high of 20C.

Christchurch
Morning and evening low cloud, otherwise fine. Northeasterly breezes developing and a high of 22C.

Dunedin
Fine apart from low cloud morning and night. Northeasterly breezes developing and a high of 20C.

Queenstown
Morning cloud clearing to fine, but chance afternoon shower. Light winds and a high of 24C.​