MetService meteorologist Mmathapelo Makgabutlane said the weather system would send thundery showers over most regions today and into tomorrow.
Auckland is in the firing line for rush-hour thunderstorms as the rain band passes over.
MetService said there was a risk of localised heavy rain with intensities of 10-20mm per hour and small hail.
Makgabutlane said the already saturated ground could mean there is some surface flooding.
She said as the rain band passes over, there would be a brief period of heavy rain, followed by showers.
“There is a possibility of a more intense rainfall as they move across.”
The rain was also expected to hit Coromandel Peninsula and western Bay of Plenty this evening.
Makgabutlane said Northland had already received some heavy rain this morning, which would linger for the rest of the day.
MetService is also forecasting a moderate risk of thunderstorms in western regions of both islands from this afternoon through until tonight.
Makgabutlane said although the incoming rain was not expected to reach warning criteria, MetService was keeping a close eye on the situation.
“We want people to be aware there is a wet period ahead … and there will be some wetter periods within that.”
Further south, road snowfall warnings are in place as alpine passes in the South Island plunge back into wintry conditions.
From 3pm until 9pm, 1-3cm of snow is expected to accumulate on Arthur’s Pass (SH73).
Porters Pass (SH73) is under a road snowfall warning from 2pm until midnight, with 3-8cm expected to fall around the summit.
A road snowfall warning is already active for Lindis Pass, where 1-3cm is forecast to fall. The snowfall warning is in place until 1pm.
Rachel Maher is an Auckland-based reporter who covers breaking news. She has worked for the Herald since 2022.
