MetService has issued a severe weather warning with heavy rain forecast for northern and western parts of New Zealand.

A front over the central South Island is drifting south today and tomorrow to lie slow moving near Fiordland before moving west across the South Island during Monday. Another front moves over the North Island during Sunday and Monday.

Heavy Rain Watches and Warnings are in place for northern and western parts of the country and Strong Wind Watches are also in force for the upper North Island.

People are advised to stay up to date with the latest forecasts in case any changes are made, or further areas are added.

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

Area: Tasman about and west of Motueka
Valid: 18 hours from 12:00am Mon 29 May to 6:00pm Mon 29 May
Forecast: Expect 80 to 120 mm of rain about the ranges, with 40 to 70 mm nearer the coast. Peak rates of 15 to 25 mm/h about the ranges.

Area: Westland from around Bruce Bay to Greymouth
Valid: 8 hours from 9:00am Sat 27 May to 5:00pm Sat 27 May
Forecast: On top of what has already fallen, expect another 40 to 60 mm of rain about the ranges and lesser amounts near the coast. Peak rates of 15 to 25 mm/h. Thunderstorms, mainly this morning.
Note: a few heavy showers are expected to persist after 5pm, but widespread heavy rain is expected to have eased.

A Heavy Rain Watch is in place for these regions:

Area: Northland
Valid: 15 hours from 3:00pm Sun 28 May to 6:00am Mon 29 May
Forecast: Periods of heavy rain. Rainfall amounts may approach warning criteria.

Area: Auckland including Great Barrier Island and Coromandel Peninsula
Valid: 15 hours from 9:00pm Sun 28 May to 12:00pm Mon 29 May
Forecast: Periods of heavy rain. Rainfall amounts may approach warning criteria.

Area: Bay of Plenty about and west of Whakatane
Valid: 15 hours from 3:00am Mon 29 May to 6:00pm Mon 29 May
Forecast: Periods of heavy rain. Rainfall amounts may approach warning criteria.

Area: Bay of Plenty east of Whakatane and Gisborne north of Tokomaru Bay
Valid: 15 hours from 9:00am Mon 29 May to 12:00am Tue 30 May
Forecast: Periods of heavy rain. Rainfall amounts may approach warning criteria.

Area: Mount Taranaki
Valid: 12 hours from 12:00am Mon 29 May to 12:00pm Mon 29 May
Forecast: Periods of heavy rain. Rainfall amounts may approach warning criteria.

Area: Richmond and Bryant ranges including the Rai Valley, also Tasman east of Motueka but excluding the Nelson Lakes
Valid: 15 hours from 3:00am Mon 29 May to 6:00pm Mon 29 May
Forecast: Periods of heavy rain. Rainfall amounts may approach warning criteria.

Area: Westland south of Bruce Bay
Valid: 12 hours from 12:00am Sun 28 May to 12:00pm Sun 28 May
Forecast: Periods of heavy rain. Rainfall amounts may approach warning criteria.
Note, more rain expected on Monday and this Watch may be extended or upgraded to a warning.

Area: Fiordland
Valid: 38 hours from 4:00am Sun 28 May to 6:00pm Mon 29 May
Forecast: Periods of heavy rain. Rainfall amounts may approach warning criteria.

A Strong Wind Watch is in place for these regions:
Area: Northland
Valid: 9 hours from 6:00pm Sun 28 May to 3:00am Mon 29 May
Forecast: Northeast winds may approach severe gale in exposed places.

Area: Auckland including Great Barrier Island
Valid: 12 hours from 9:00pm Sun 28 May to 9:00am Mon 29 May
Forecast: Northeast winds may approach severe gale in exposed places.

Watches no longer in Force
Strong Wind Watch lifted for Canterbury Plains and Christchurch: The threat of northwest winds reaching severe gale has passed and the Watch is now lifted.

Strong Wind Watch lifted for North Otago and Dunedin: The threat of northwest winds reaching severe gale has passed and the Watch is now lifted.