Batten down the hatches - heavy rain, lightning and strong winds are surging up the country.
Wellington has been hammered by heavy rain, lightning and thunderclaps this morning - and the storm is on its way north.
MetService meteorologist Hannah Moes says the capital's had strong winds - with gusts recording at 117km/h after the front came from the south overnight.
She says there's also been torrential downpours, with 19mm of rain falling in the last hour.
The downpour has led to surface flooding on State Highway 1 south of Johnsonville and on State Highway 2 at Petone. Rail services on the Johnsonville line have also been affected by heavy rain.
A Wellington City Council spokeswoman said flooding was widely spread around the city, with the main affected areas Kilbirnie, Tawa, Khandallah, Strathmore Park, Roseneath, Newlands, Miramar, and Johnsonville.
"All reported incidents are logged with contractors so have either been fixed already, are being attended to, or they're on their way."
Fire and Emergency NZ shift manager Murray Dunbar said they had received about 10 calls in relation to surface flooding in Wellington.
In one instance a person drove into the floodwater on Kenmore St and could not move the vehicle, or get out of it, until the flooding was cleared, he said.
"There has been a little bit of surface flooding around Kenmore St and Bracken Rd in Newlands - that's been cleared by clearing the drains."
There was also a bit of flooding on Hutt Rd and in Tawa, he said.
Meanwhile fire investigators are looking into what caused a fire at a central Wellington motel this morning.
Seven fire appliances attended the blaze, which was contained to a single room at the Harbour City Motor Inn, on Webb Street.
Fire and Emergency New Zealand shift manager Murray Dunbar says crews were called at 8.08am. A specialist fire and emergency investigator is in attendance and the fire's been extinguished.
Cold front heading north, will hit Auckland later today
An active cold front with a band of heavy rain is moving quickly north from the South Island this morning to lie over the central and northern North Island.
MetService meteorologist Andrew James said some southern stations had recorded considerable rain overnight, especially in the western ranges.
Both Arthur's Pass and Milford Sound received over 100mm in the past 18 hours, while a station at Cropp River had 173mm in the past 24 hours.
There is a strong wind watch in place for most of the North Island throughout parts of the day, including Northland, Auckland, Taranaki, Whanganui, Manawatū and Wairarapa.
A strong wind warning is in place for Wellington and the Marlborough Sounds.
The gusts that reach Auckland could hit 90km/h, while at midday a downpour of heavy rain is expected, James said.
"After that front goes through, in behind there is quite a lot of cold air up high which can cause some thunderstorms."
Thunderstorms and hail are possible in Auckland during the evening, James said.
The bad weather is expected to clear in Auckland tomorrow morning, he said.
"However, then there is another feature coming on Tuesday," he said.
"So we are in this westerly pattern where we have got these features lined up and coming over the country again and again and again for the next week or so."
Main centre forecast
Cloudy periods and a few showers, but rain around midday. Strong northerlies turn westerly afternoon. High 18C, low 8C
Rain around midday, otherwise showers. Thunderstorms and hail possible from evening. Strong northerly gust 90 km/h turning westerly. 17C, 10C
Rain around midday, otherwise showers. Thunderstorms and hail from afternoon. Strong northerlies turning westerly afternoon. 16C, 6C
Showers, but a period of afternoon rain. Strengthening northerlies turning westerly afternoon. 17C, 8C
Morning rain, briefly heavy, then a few showers, possibly thundery with hail. Northerly gales, gusting 120 km/h, easing from afternoon. 14C, 9C
Rain, briefly heavy, easing to showers late morning as strong northerlies turn southwest, then becoming fine. 15C, 3C
Cloudy periods. A few showers developing afternoon as northeast turns southwest, possibly heavy and thundery with hail. 16C, 0C
Occasional showers. Strong northeasterlies turning southwest in the morning. 13C, 3C