Weather: Heavy rain, thunderstorm threat as lightning strikes blast North Island

The North Island is threatened by rain and thunderstorms as lightning strikes blast their way towards the Waikato.

A low-pressure system in the Tasman Sea is sending waves of strong wind and wet weather to much of the North Island on Monday.

Earlier today a strong southerly change swept up from the South Island to Wellington with gale-force southerlies through the Cook Strait. And MetService warns this is heading back to the capital.

"Wellingtonians I hope you enjoyed the brief respite from the southerlies because they're due to return shortly and they're looking to linger through the week," it says.

As the low-pressure system moves onto the North Island from the west, it brings the risk of thunderstorms and heavy rain.

"A heavy rain watch has just been issued for Taranaki," MetService says.

"This radar and lightning composite grabbed at 7:43am today shows lightning strikes moving towards Waitomo and Waikato associated with an approaching front."

Auckland is next in the firing line as a band of heavy showers pushes towards the city from the west.

Further south, the southerlies have developed a band of intense showers over the Canterbury Plains, extending northwest across the Alps.

"A chilly start for many down south, with frosts in Otago overnight, and Blenheim down to just 5C at 7am," MetService says.

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