Thunderstorms, heavy rain and severe gales are all being forecast for later today.

A severe weather watch is in force for the Bay of Plenty and warning has been issued for the Coromandel Peninsula.

"A large, deep, complex low pressure system moves slowly southeast towards northern New Zealand during today and Monday," says the MetService.

"An associated front is forecast to move slowly southwards over northern New Zealand on Monday, with heavy rain and easterly gales preceding the front.

"Large waves are also expected to affect eastern coasts of the upper North Island.

"Warnings and Watches for heavy rain and severe east to southeast gales are in force."

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

Area: Northland
Valid: 18 hours from 12pm Sun 29 Oct to 6am Mon 30 Oct
Forecast: Expect 80 to 110 mm of rain, especially in eastern areas. Peak rates of 15 to 25 mm/h from this evening, and thunderstorms possible Monday morning.
Note: Scattered heavy showers and thunderstorms are forecast after the heavy rain has eased on Monday.

Area: Coromandel Peninsula
Valid: 18 hours from 9pm Sun 29 Oct to 3pm Mon 30 Oct
Forecast: Expect 100 to 140 mm of rain. Peak rates of 15 to 25 mm/h from Monday morning, with thunderstorms possible.

Area: Tairawhiti/Gisborne from Tolaga Bay northwards
Valid: 18 hours from 3am Mon 30 Oct to 9pm Mon 30 Oct
Forecast: Expect 120 to 170 mm of rain, especially about the ranges. Peak rates of 15 to 25 mm/h.

Heavy Rain Watch

Area: Auckland and Great Barrier Island
Valid: 15 hours from 6pm Sun 29 Oct to 9am Mon 30 Oct
Forecast: Periods of heavy rain. Rainfall amounts may approach warning criteria, especially about Great Barrier Island and North Auckland, where thunderstorms are possible Monday morning.
Note: Scattered heavy showers and thunderstorms are forecast after the heavy rain has eased on Monday.

Area: Bay of Plenty north of Tauranga
Valid: 18 hours from 12am Mon 30 Oct to 6pm Mon 30 Oct
Forecast: Periods of heavy rain, and amounts may approach warning criteria.

Area: Tairawhiti/Gisborne south of Tolaga Bay
Valid: 12 hours from 10am Mon 30 Oct to 10pm Mon 30 Oct
Forecast: Periods of heavy rain. Amounts may approach warning criteria, especially about the ranges.

Area: The western ranges of Hawke's Bay south of State Highway 5
Valid: 12 hours from 12pm Mon 30 Oct to 120am Tue 31 Oct
Forecast: Periods of heavy rain, and amounts may approach warning criteria.

Strong Wind Watch
Area: Auckland south of Whangaparaoa
Valid: 15 hours from 6pm Sun 29 Oct to 9am Mon 30 Oct
Forecast: East to southeast winds may approach severe gale in exposed places.

Area: The Kaimai Range and eastern Waikato
Valid: 11 hours from 12am Mon 30 Oct to 11am Mon 30 Oct
Forecast: East to southeast winds may approach severe gale in exposed places.