UPDATED 10.47AM: The MetService has issued a severe weather warning for the Bay of Plenty.

Heavy rain is being forcast for tomorrow.

Rain is expected to hit the Bay this weekend before making way to fine weather next week. Photo; MetService.

In the 12 to 15 hours from midday Saturday 80 or 90mm is likely to accumulate. Rainfall intensities of 20-25mm/hr are possible Saturday evening.

This rain has the potential to cause rivers and streams to rise quickly, surface flooding and make driving conditions hazardous.

Earlier:

While today looks like bringing relatively settled conditions across the country, all eyes are on a significant weather system set to affect New Zealand over the weekend.

A low pressure system developing over the Tasman Sea is set to intensify as it approaches from the west during Friday.

Meanwhile, a frontal system approaches the south of the country late on Friday, bringing rain to much of the South Island during Saturday, with snow falling to low levels.

This rain is expected to move up the country over the weekend.

'These weather systems are set to bring severe weather right across the country during the weekend,” says MetService meteorologist Rob Kerr.

'As heavy rain and strong winds affect the North Island and the top of the South Island on Saturday, the cold southerly change further south will have a dramatic effect on where the heaviest snow falls are as the frontal system moves northwards.

'The cold outbreak will quickly sweep over the North Island on Sunday as the low moves away to the east, and could result in significant snowfall about some lower North Island ranges.

'The MetService team will be posting regular forecast and warning updates on metservice.com and via the MetService Facebook and Twitter feeds as this event unfolds.”

Looking beyond the weekend, the southwest flow eases on Sunday as a broad ridge approaches from the west, moving over all of New Zealand during Tuesday and Wednesday.

This means a return to fine days with frosty starts for most Kiwis.