It's going to rain this weekend with some heavy falls possible, as another sub-tropical low pressure system passes down the North Island's West Coast.

How heavy the rain will be and how long it lasts depends on the pace of a trough associated with the weather system, which MetService meteorologists are keeping an eye on.

Heavy rain watches and warnings for the Bay of Plenty may be issued on Friday says meteorologist Lisa Murray.

'What we will get is a lot of rainfall. We are going to have some rain and some heavy falls probably coming in tomorrow,” says Lisa.

'The north east flow will push it right in there to you guys. It's not looking like the best of weekends, I would have to say.”

Temperatures will remain warm, 23 maximum, 21 minimum – the same as the overnight low expected Saturday.

It will be muggy and humid, and if the associated trough should stall over the Bay of Plenty the heavy rain will linger. And the rain will continue through to Monday and possibly Tuesday next week.

It's the sort of forecast where she recommends gutters, spouting and drains are checked and cleared, says Lisa.

'The wind is not expected to be as strong as last time, there is that,” says Lisa.

Wind will be east to north east, depending on the time of day and will be ‘pretty fresh' at 45-50kmh, and stronger gusts.