Another unwelcome bout of bad weather is set to hit the upper North Island, arriving in the Far North this afternoon.

A heavy rain watch is in place for Northland, while Auckland, Coromandel and the Bay of Plenty can expect to be in the firing line later tonight and into Friday, with severe gale force winds forecast for some places.

MetService meteorologist Mmathapelo Makgabutlane told Morning Report the new system is more of the same subtropical flow Aotearoa has experienced this year.

"We've had quite an active year so far that has brought really heavy rain to the upper North Island, and that trend continues with this next system that we are expecting.

"It is coming from the subtropical regions so it is warmer as it's moving through so people will be feeling that in the temperature, but what will be most felt will be that rain as well as the wind.

"The one saving grace from this system in particular is that it does move through fairly quickly, so that means that over widespread areas probably not as much rain as we would have seen last week.

"However, that said, we do expect localised areas to still be in with a possibility of that heavier rain, especially considering the fact that we could see some potential thunderstorms embedded in that rain band."

Northland and other regions have already soaked up a lot of rain, which raises the chance of more flooding problems.

"The ground's very sodden, so it might not actually take those high rainfall accumulations that we would see to bring surface flooding."

She says that for anywhere that is already under a heavy rain watch or upgraded to a warning, "those impacts such as flooding and possible land slips are still a possibility".

As the system moves through the country it will head towards Bay of Plenty and Tai Rāwhiti, and while those areas are not under a watch, that could change, says Makgabutlane.

The South Island's West Coast experienced its own bout of heavy rain overnight - and it is still falling now - while there was some snow in Central Otago.

-RNZ.