Conditions are expected to remain relatively settled through Tuesday as a ridge of high pressure moves away to the east, with minimal risk of severe weather.
However, by Wednesday, the subtropical low is forecast to move west of the North Island, bringing rain and strengthening northeasterly winds, particularly to northern regions.
There is low confidence in warning-level rain for Northland, or severe gale northeasterly winds over Northland and northern Auckland.
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.
There is a moderate chance of rainfall and strong winds along the west coast of the country on Thursday. Photo / MetService
Auckland, the Coromandel Peninsula, Bay of Plenty, Taranaki, Tasman and parts of the West Coast face a lower chance of significant rainfall.
There is moderate confidence that severe gale northeasterly winds could affect parts of Northland, Auckland and the northern Coromandel Peninsula.
A low risk has been put in place for other areas, including Waikato, Taranaki and Banks Peninsula.
Forecasters note the exact impacts will depend on the track of the low as it moves south from the subtropics.
By Friday, the low is expected to move on to the South Island, with associated rain spreading eastwards across the country.
Martino said while the term may sound similar to a tropical system, a subtropical low simply refers to where the system forms.
“What we’re talking about is a low that forms in the subtropics, roughly between 20 and 35 degrees south,” she said.
Because these systems form in warmer regions, they can carry significant moisture, which can then be drawn down over New Zealand, increasing the risk of heavy rainfall.