Parts of the Canterbury High Country, Cook Strait and Wellington are in for severe northwesterly gales on Friday.
The rain will ease as it moves north, but another “more active” system from over the Tasman Sea moves onto New Zealand late Friday.
Lyons said it will bring more rain to the North Island over the weekend.
She said this was due to the terrain in the South Island. “Which is why we’ve got the high potential of severe weather for those areas of the South Island.
“But it will be relatively quick-moving.”
Metservice wasn’t too concerned about the first system for Auckland, but a second system could have more impact.
“There’s lots of time for that feature to change and for our focus to change as well,” Lyons said.
Depending on the intensity of rainfall, she said, Metservice would issue warnings to the public.
While the entire country is set to be hit with rainfall, warmer days follow in the second half of the week.
Most parts of the country will see temperatures at or exceeding 20C from Wednesday, Metservice said.
Christchurch and Gisborne are expected to have maximum temperatures of 23C.
Malisha Kumar is a multimedia journalist based in Hamilton. She joined the Waikato Herald in 2023 after working for Radio 1XX in Whakatāne.