Heavy rain warnings for sodden Northland, Auckland and Coromandel

Heavy rain watches have been upgraded to warnings as downpours close in on an already saturated Northland, parts of Auckland, and the Coromandel Peninsula.

MetService has issued orange heavy rain warnings for Monday and Tuesday, with a strong, humid easterly flow set to deliver prolonged rain, possible severe thunderstorms, and localised downpours.

In Northland, up to 110mm of rain is expected across a broad area between Monday night and Tuesday afternoon, with northern and eastern areas possibly receiving 150mm or more.

For Auckland north of the Harbour Bridge, Great Barrier Island and the Coromandel Peninsula, heavy rain is forecast from early Tuesday, with totals generally between 80 and 120mm, but up to 140mm in eastern and higher areas.

More heavy rain was expected on Wednesday, with another watch or warning potentially to be issued.

MetService said a low of tropical origin, moving southeast, was expected to be approaching the North Island on Wednesday, bringing heavy rain and strong east to northeast winds.

"The path and strength of the low originating from the tropics is very uncertain," the forecaster said.

"It is likely that it will pass over the central North Island, and may extend a trough onto the South Island. The low and associated fronts should move off to the east of mainland New Zealand late in the day. Heavy rain and strong winds are possible in many northern and central parts of the country."

The uncertainty of the situation meant the possibility of "significant changes" in these areas with subsequent forecasting, it added.

Northland was slammed by torrential rain early on Sunday morning that washed out roads and bridges, cutting off some communities along the east coast of the region.

Up to 200mm of rain fell in localised areas, MetService said, causing "significant flooding" which damaged homes and a recently renovated community hall in Ōakura.

MetService meteorologist Devlin Lynden said yesterday a persistent moisture-laden easterly flow drawn down from the tropics had brought the rain to Northland.

"As the moisture is pushed onto the coastal ranges, it is forced upward, this cools the air down and allows that moisture to condense and fall out as rain... and a lot of it."

Civil Defence Northland said it was "actively preparing" for further heavy rain by monitoring forecasts alongside MetService and hydrologists, with planning and coordination meetings with councils and key stakeholders taking place this morning.

"Thanks to the efforts of emergency services, council teams, and volunteer community response groups, access has now been restored to nearly all previously affected areas across Whangaruru and much of the Whangārei District."

Residents were encouraged to secure outdoor furniture and loose items, clear drains and gutters, move valuables and vehicles away from flood‑prone areas, relocate stock from low‑lying land and bring pets indoors, ensure you have food, water, medications, torches, and charged devices, as well as getting a grab bag and evacuation plan ready.

NZTA also announced on Sunday that State Highway 2 through the Waioweka Gorge, the main route between Gisborne and Ōpōtiki, was likely to remain closed for several weeks after heavy rainfall on Friday triggered dozens of slips, washed out sections of road and forced more than 40 stranded people to be rescued by helicopter.

Around 322mm of rain fell in 48 hours — double the area’s January average — causing up to 40 slips on the state highway.

Heavy Rain Warning - Orange

Northland - 17 hours from 9pm Monday to 2pm Tuesday

Auckland north of the Harbour Bridge and Great Barrier Island - 16 hours from 2am Tuesday to 6pm Tuesday

Coromandel Peninsula - 24 hours from 2am Tuesday to 2am Wednesday