Heavy rain is expected for the Bay of Plenty, as well as Northland, Coromandel Peninsula and Gisborne from Tolaga Bay northwards as a heavy rain warning has been put in place.

A complex low pressure system over the northern Tasman Sea is forecast to move east across the upper North Island today and through Christmas Day.

Fronts associated with this low are expected to spread across the North Island during this period bringing periods of heavy rain and possible thunderstorms to the northern districts.

In a statement issued by MetService it is the heaviest rain is expected in Northland, Coromandel Peninsula, Bay of Plenty and Gisborne for Tolaga Bay northwards and a heavy rain warning in in force.

'This is likely to be a significant event for these areas, especially for parts of the Coromandel Peninsula and Western Bay of Plenty, where further flooding is likely.

'Note, the combination of the approaching low, strong onshore winds and king tides late Monday and during Christmas Day could cause some coastal flooding about eastern coasts.”

Heavy rain may cause streams and rivers to rise rapidly. Surface flooding and slips are also possible and driving conditions may be hazardous.

Heavy Rain Warning:

Area: Bay Of Plenty, including Rotorua, also Gisborne from Tolaga Bay northwards
Valid: 24 hours from 12:00 pm Monday to 12:00 pm Tuesday
Forecast: Periods of rain, heavy at times. Expect 100 to 130mm to accumulate, especially in areas west of about Whakatane. Peak intensities 20 to 30mm per hour from early evening through into early morning, then rain gradually easing from the west.

Area: Northland
Valid: 12 hours from 9:00 am to 9:00 pm Monday
Forecast: A period of heavy rain. Expect 50 to 70mm. Peak intensities20 to 30mm per hour and possibly higher. Thunderstorms also possible.

Area: Coromandel Peninsula
Valid: 21 hours from 9:00 am Monday to 6:00 am Tuesday
Forecast: Periods of heavy rain. Expect 90 to 110mm to accumulate. Peak intensities of 20 to 30mm per hour or possibly higher. Thunderstorms also possible.