Auckland is set for more than a day of rain as a subtropical storm brings downpours and severe gales to the top of the North Island, and a fresh threat of flooding and slips.
Eight weather alerts have been issued by MetService as a tropical low moves into the Tasman Sea, bringing significant rain and strengthening easterly winds from Wednesday.
A 38-hour heavy rain warning has been issued for Northland starting from 7pm tomorrow, with up to 250mm of rain possible in northern and eastern areas.
MetService warned that streams and rivers may rise rapidly, causing surface flooding, slips and difficult driving conditions. There is a moderate chance of the forecast being upgraded to a red warning.
Stormy conditions will then move south to Tāmaki Makaurau early Thursday morning, with a 33-hour heavy rain watch from 6am.
Heavy rain warnings have also been issued for the Coromandel Peninsula and Bay of Plenty, west of Whakatāne.
Tasman, west of Motueka in the upper South Island, is also set for heavy rainfall.
People in affected areas are advised to stay prepared by clearing drains and gutters, watch for flooding, debris, slips and poor visibility, allow extra travel time and drive to conditions, with power outages possible.
Earlier, MetService meteorologist Brian Mercer said forecasters were monitoring a developing subtropical system north of Aotearoa that could bring wet, windy weather.
The low-pressure system, which was near Vanuatu yesterday afternoon, is heading south over warm seas, where it could briefly develop into a tropical cyclone, before weakening.
“It won’t last as a cyclone very long because it’s moving out of the tropics and changing its nature,” Mercer said.
The subtropical low is forecast to move west of the North Island tomorrow, bringing rain and strengthening northeasterly winds, particularly to northern regions.
By Thursday, the system is expected to intensify further while remaining west of the country, pushing bands of rain on to both islands and strengthening winds.
Windy and wet weather from Wednesday 🌧️💨
— MetService NZ (@MetService) March 23, 2026
Heavy Rain, strong winds and large waves will begin to impact the country from Wednesday as a low from the tropics moves into the Tasman Sea.
🟡 Yellow Heavy Rain and Strong Wind Watches have been issued for Northland from Wednesday… pic.twitter.com/H5vJsKxKe1
Conditions today are expected to be similar to yesterday, though with high cloud drifting down from the tropics.
“That’s going to have the effect of keeping the temperatures that little bit milder for the North Island,” Mercer said.
Highs of about 23C are forecast across the upper North Island from Kaitāia to Auckland, with similar temperatures expected in Waikato.
Further south, parts of the Wairarapa, including Dannevirke and Masterton, could also have warm conditions, with developing northwesterly winds helping lift temperatures through the afternoon.
Wellington is forecast to reach a high of about 22C today, with northerly winds strengthening during the morning after several days of light winds.
“There is just a chance that we could get a shower or two during the afternoon, however, by evening that risk goes away and it’ll be relatively fine, though there may be bits of cloud around,” Mercer said.
Across the South Island, areas of cloud and fog may develop in inland Marlborough and Otago early in the day, though these should clear as temperatures rise.
“There’s still quite a bit of heating in the sun so those will burn off during the morning,” Mercer said.
Dunedin is expected to reach a high of 21C today, with Christchurch topping out at 23C.
Most of the South Island is expected to remain fine throughout today, though Fiordland and Southland could have a few spots of rain in the morning, becoming slightly more widespread along coastal areas later.
Forecasters say the outlook will become clearer over the next few days as the subtropical system moves south towards New Zealand.