A severe weather warning for heavy rain has been issued for Bay of Plenty.

Up to 80-120mm of rain is expected to accumulate, especially about the ranges, across Tuesday night and into Wednesday.

MetService is forecasting a low to move southeast over the country on Wednesday, bringing rain with heavy falls to the North Island and upper South Island. Meanwhile, the remainder of the South Island remains dry in the east, but rain or a few showers affect the west and Far South.

Heavy rain watches have also been issued for Northland, Auckland, Coromandel Peninsula and Mt Taranaki.

Rain and strong north-easterly winds develop over Northland Tuesday morning, spreading southwards to Taupo by the end of the day and over the remainder of the North Island early Wednesday as a deep low crosses the country.

'There is also a moderate risk of thunderstorms over Northland during Tuesday afternoon and evening, which then extends towards Auckland at night and into Bay of Plenty on Wednesday,” says MetService meteorologist Amy Rossiter.

Whilst we may be in for some wet and stormy weather, temperatures in the Bay of Plenty are set to increase after the recent chilly nights. Temperatures overnight Tuesday are expected to be above average.

'Models are forecasting Whakatane to be well above average with a minimum of 18 degrees overnight Tuesday.” Rossiter said.

Over the South Island, rain is expected to develop in the northwest of the South Island Tuesday evening and spread into Marlborough for a time on Wednesday as the low moves southeast across the country.

Further south, eastern regions remain dry while western areas continue to see a few showers or rain in the onshore flow, clearing for a time on Wednesday.

A front also approaches the Far South on Wednesday bringing brief scattered rain to Southland and Clutha, before becoming slow moving and weakening away early Thursday.