A storm could rapidly develop near the upper North Island this weekend, bringing more heavy rain to Northland, Auckland and the Coromandel Peninsula.
Early forecasts show low-pressure systems in the Tasman and another brewing around New Caledonia will arrive on Saturday morning.
It follows hundreds of passengers having had domestic flights delayed or cancelled in the upper North Island as a result of low cloud on Wednesday morning.
Storm may develop near Upper North Island
On Tuesday, thick fog also affected some upper North Island airports, including 20 domestic flight cancellations at Auckland Airport alone.
NIWA meteorologist Chris Brandolino told Morning Report on Wednesday it could be a wet and windy end to the school holidays.
"It looks like rain will unfold Friday night across the upper North Island, so Northland and Auckland, and that rain could be heavy, potentially," Brandolino said.
"It gets into the Coromandel late Friday night, early Saturday morning, and then perhaps grazing the far eastern Bay of Plenty.
"And then, Tairāwhiti - Gisborne, Hawke's Bay will likely see some pretty good rain as you work your way through much of the day on Saturday."
Brandolino said there could be up to 100mm of rain.
MetService meteorologist Lewis Ferris said on Monday northern and eastern areas of the North Island may be affected by strong winds, heavy rain and dangerous coastal conditions.
"While it's far too early to try nail down any firm details, we're recommending people around the north and east of the North Island keep an eye on the forecasts for the end of the week, and especially the daily updates to our Severe Weather Outlook."
However, much of the eastern part of the South Island, from Canterbury down to eastern Otago, even maybe eastern Southland, is going to be largely dry and devoid of any rain over the next several days, Brandolino said.
"In fact, that may be a problem. Winter is a wet time of the year. It's really important in those agricultural areas, such as the eastern South Island, that we get that groundwater recharge."