Heavy rain and northwest gales for parts of southern and central New Zealand

An active low pressure system moves east across the South Island early Sunday, while an associated front moves across the North Island during Sunday and early Monday. This weather system is forecast to bring a period of heavy rain and strong northwest winds.

Warnings and Watches for heavy rain and northwest gales are in force for areas of both Islands.

Please keep up to date with the latest forecasts.

Area: Taranaki Maunga

Period: 18hrs from midnight Sat, 17 May - 6pm Sun, 18 May

Forecast: Expect 150 to 200 mm of rain. Peak rates of 25 to 35 mm/h expected Sunday afternoon. Minimal chance of upgrading to a Red Warning.

Impact: Streams and rivers may rise rapidly. Surface flooding, slips, and difficult driving conditions possible.

Action: Clear your drains and gutters to prepare for heavy rain. Avoid low-lying areas and drive cautiously. Preparedness advice.

Area: Tararua Range

Period: 10hrs from 6am - 4pm Sun, 18 May

Forecast: Rain is forecast to become heavy Sunday morning. Expect 70 to 120 mm to accumulate. Peak intensities 25 to 30 mm/h. Minimal chance of upgrading to a Red Warning.

Impact: Streams and rivers may rise rapidly. Surface flooding, slips, and difficult driving conditions possible.

Action: Clear your drains and gutters to prepare for heavy rain. Avoid low-lying areas and drive cautiously. Preparedness advice.

Area: Ranges of the Westland District

Period: 8hrs from 8pm Sat, 17 May - 4am Sun, 18 May

Forecast: Expect 90 to 140 mm of rain on top of what has already accumulated. Peak rates of 20 to 30 mm/h with thunderstorms possible. Minimal chance of upgrading to a Red Warning.

Impact: Streams and rivers may rise rapidly. Surface flooding, slips, and difficult driving conditions possible.

Action: Clear your drains and gutters to prepare for heavy rain. Avoid low-lying areas and drive cautiously. Preparedness advice.

Area: Headwaters of the Canterbury Lakes and Rivers about and south of Arthur's Pass

Period: 8hrs from 8pm Sat, 17 May - 4am Sun, 18 May

Forecast: On top of the rain that has already accumulated, expect 90 to 130 mm about the main divide, and 60 to 100 mm 15 kilometres further east. Peak intensities 15 to 25 mm/h. Thunderstorms possible. Minimal chance of upgrading to a Red Warning.

Impact: Streams and rivers may rise rapidly. Surface flooding, slips, and difficult driving conditions possible.

Action: Clear your drains and gutters to prepare for heavy rain. Avoid low-lying areas and drive cautiously. Preparedness advice.

Area: Ranges of Tasman northwest of Motueka

Period: 11hrs from 10pm Sat, 17 May - 9am Sun, 18 May

Forecast: Expect 90 to 140 mm to accumulate. Peak intensities 20 to 25 mm/h. Minimal chance of upgrading to a Red Warning.

Impact: Streams and rivers may rise rapidly. Surface flooding, slips, and difficult driving conditions possible.

Action: Clear your drains and gutters to prepare for heavy rain. Avoid low-lying areas and drive cautiously. Preparedness advice.

Area: Buller

Period: 10hrs from 10pm Sat, 17 May - 8am Sun, 18 May

Forecast: Expect 60 to 110 mm to accumulate. Peak intensities 20 to 25 mm/h. Minimal chance of upgrading to a Red Warning.

Impact: Streams and rivers may rise rapidly. Surface flooding, slips, and difficult driving conditions possible.

Action: Clear your drains and gutters to prepare for heavy rain. Avoid low-lying areas and drive cautiously. Preparedness advice.

Area: Marlborough

Period: 8hrs from midnight Sat, 17 May - 8am Sun, 18 May

Forecast: Severe gale northwest winds gusting 120 km/h in exposed places. Minimal chance of upgrading to a Red Warning.

Impact: Damage to trees, powerlines, and unsecured structures possible. Driving may be difficult, especially for high-sided vehicles and motorcycles.

Action: Prepare your property by securing items that can be picked up by strong winds. Drive cautiously. Preparedness advice.

Area: Wellington

Period: 12hrs from midnight Sat, 17 May - noon Sun, 18 May

Forecast: Severe gale northwest winds gusting 120 km/h in exposed places. Minimal chance of upgrading to a Red Warning.

Impact: Damage to trees, powerlines, and unsecured structures possible. Driving may be difficult, especially for high-sided vehicles and motorcycles.

Action: Prepare your property by securing items that can be picked up by strong winds. Drive cautiously. Preparedness advice.

Area: Canterbury High Country

Period: 8hrs from 8pm Sat, 17 May - 4am Sun, 18 May

Forecast: Severe gale northwesterlies gusting 120 km/h in exposed places. Minimal chance of upgrading to a Red Warning.

Impact: Damage to trees, powerlines, and unsecured structures possible. Driving may be difficult, especially for high-sided vehicles and motorcycles.

Action: Prepare your property by securing items that can be picked up by strong winds. Drive cautiously. Preparedness advice.

Issued: 8:39pm Sat, 17 May
Next update: 10am Sun, 18 May
Action advice supplied by the National Emergency Management Agency.