A low pressure system is expected to move slowly across northern New Zealand from today through to Saturday, directing moist northeast winds with several embedded fronts across northern and central regions.

Periods of heavy rain and possible thunderstorms are forecast from Northland to northern Auckland, and southwards to western Bay of Plenty and northern Tairawhiti/Gisborne, and also the Central Hawkes Bay ranges and eastern Marlborough.

This rain will affect areas that are already saturated from recent rain events.

Heavy rain watches and warnings are in force.

A Heavy Rain Watch is in place for:

Area: Coromandel Peninsula and Bay of Plenty west of Te Puke
Valid: 35 hours from 1:00am Thu 22 Jun to 12:00pm Fri 23 Jun
Forecast: Periods of heavy rain and possible thunderstorms. Rainfall accumulations may approach warning criteria.

Area: Northland
Valid: 19 hours from 9:00am Wed 21 Jun to 4:00am Thu 22 Jun
Forecast: Periods of heavy rain and possible thunderstorms, spreading southwards today. Rainfall accumulations may approach warning criteria, especially in the north and east.

Area: Auckland about and north of Whangaparaoa, including Great Barrier Island
Valid: 12 hours from 9:00pm Wed 21 Jun to 9:00am Thu 22 Jun
Forecast: Periods of heavy rain and possible thunderstorms. Rainfall accumulations may approach warning criteria.

Area: The Ruahine Range and Kaweka Forest Park
Valid: 21 hours from 3:00am Thu 22 Jun to 12:00am Fri 23 Jun
Forecast: Periods of heavy rain. Rainfall accumulations may approach warning criteria.

Periods of heavy rain are due to return late Friday and persist through Saturday, also possibly affecting the coastal hills south of Napier during this time.

Area: Eastern Marlborough, south of Ward
Valid: 51 hours from 3:00pm Thu 22 Jun to 6:00pm Sat 24 Jun
Forecast: Periods of heavy rain. Rainfall accumulations may approach warning criteria.

Heavy Rain Warning

A Heavy Rain Warning is in place for Tairawhiti/Gisborne about and north of Tolaga Bay. This is valid for 24 hours from 3pm Wednesday June 21 to 3pm Thursday June 22. Expect 100 to 140 mm of rain in the ranges, and 60 to 90 mm of rain about the coast. Thunderstorms are possible, and rain peak intensities may reach 15 to 25 mm per hour.

Periods of heavy rain return early Friday and spread throughout the Tarawhiti/Gisborne region as winds turn more easterly. Heavy rain is expected to continue through the weekend, with further warnings likely to be issued.

People are advised to keep up to date with the latest forecasts in case further areas are added or upgraded.

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