Weather: Heavy rain warnings across North Island, wet week ahead

Heavy rain warnings have been issued for Northland, the Bay of Plenty and Mt Taranaki. Photo / Metservice

The country is in for a wet week, as MetService warned of heavy rain for parts of the North Island, and forecast possible thunderstorms in the South Island.

The greatest volume of water is expected to fall in already rain-sodden areas.

Northland, Bay of Plenty, and Mt Taranaki have heavy rain watches in place, with up to 80mm possible within 15 hours in places.

An already soaked Northland can expect over 50mm of rain to fall between Monday afternoon and Tuesday evening.

The Bay of Plenty, east of Kawerau, could also see heavy rain reach volumes of 80mm. Most rain should fall between Monday evening and midday Tuesday, and then later Tuesday to midday Wednesday.

The national forecaster had "moderate confidence" that Auckland and the Coromandel Peninsula could also see warning amounts of rain on Tuesday and early Wednesday.

MetService said "bursts of rain" will fall over the North Island this week, as a front lingers over the country.

The South Island may face a few thunderstorms, although the rest of the week is looking better.

The West Coast, in particular, was looking "particularly sunny" for the latter half of the week, Metservice meteorologist Stephen Glassey said.

Glassey said, "bursts of heavy rain are also likely in the upper North Island outside of the current watch areas, so it is important to stay up to date with the latest forecasts from MetService."

Another bout of rain should come on Thursday and Friday, as a low-pressure system develops over the North Island.

Glassey added, "there is always a bit of uncertainty regarding the exact distribution of rain when lows develop over New Zealand, but it looks likely that the heaviest rain later in the week will be in the east of the North Island, whereas in the first half of the week, the heaviest falls are likely in the top half of the island".