Thunderstorms and hail ahead
Thunderstorms and hail will hit much of the country this afternoon, with a small chance of localised tornados for coastal Buller and Westland.
An unstable westerly flow is covering New Zealand, with several bands of heavy showers and thunderstorms moving over the country, MetService said.
The first of band of rain struck the western North Island this morning and is moving northeast across the rest of the island this afternoon.
Aucklanders are being warned to get out their umbrellas and prepare for wild weather this afternoon, with MetService forecasting a risk of moderate thunderstorms and hail.
It could result in thunderstorms that could be accompanied by rainfall rates of 10 millimetres to 15mm an hour and 5mm to 10mm of hail.
It would also bring a few thunderstorms to Bay of Plenty and Hamilton in the late afternoon and evening. Brief heavy rain and hail would accompany these thunderstorms.
After the afternoon drenching, a new band of rain will start tracking up the country.
It will bring rain and thunderstorms along the South Island's western coastline during the day, then move onto the west coast of the North Island, stretching all the way from Auckland to Kapiti, late tonight.
These thunderstorms could be accompanied by rainfall rates of 10mm to 15mm an hour and 5mm to 10mm of hail, but might also bring a one or two small tornados to coastal Westland and Buller.
MetService meteorologist John Law said the chance of this happening was quite small and it was more likely to just be thunderstorms.
There is a low risk of one or two thunderstorms about eastern Otago and Canterbury this evening as well.
It remains chilly in Invercargill, Dunedin and Queenstown, with temperatures nudging just 7.1 degrees Celsius, 8.8C and 4.9C respectively just after 1.30pm as snowy weather closes in.
Snow is expected down to 200 metres in Fiordland this afternoon and to 300m in Southland and Otago this evening, with snow showers continuing throughout Wednesday when they are likely to lower to 300m on Banks Peninsula as well.
Sunny Hawke's Bay remains the place to be as temperatures push 18C, although this could be ruined by a late afternoon or early evening shower.
Law said the next few days would be bitterly cold, especially for the South Island.
"It's going to feel pretty unpleasant with some cold nights for some."
Snow could reach low levels in Southland, affecting roads, and might even cause trouble on the Desert Road in the North Island later in the week, he said.