Severe thunderstorms have been battering parts of the North Island today bringing torrential rain and strong winds to much of Bay of Plenty.
MetService said one of the worst-hit areas was Waihi.
Meteorologist Alec Holden said 43 millimetres of rain fell in the hour from 10am this morning at the Waihi township.
He said more rain was coming for the Bay of Plenty and the Coromandel Peninsula throughout the day.
"Especially this evening, which is when the rain watch for Coromandel kicks in," he said.
"So they've already seen quite a lot today and they will be seeing more."
Holden said the thunderstorms were currently east of Te Puke towards Whakatāne.
A severe thunderstorm warning was issued earlier today for the western Bay of Plenty and Tauranga.
MetService said its weather radar detected severe thunderstorms near Te Puke and Motiti Island around midday.
The thunderstorms were moving towards the west-southwest and were expected to lie near Te Puke, Paparoa and Paengaroa at 1pm.
They were expected to be accompanied by very heavy rain, which could cause surface or flash flooding and make driving conditions extremely hazardous.
The National Emergency Management Agency (NEMA) advised that as the storm approached, people should take shelter, preferable indoors away from windows, avoid sheltering under trees if outside, get back to land if outdoors on the water, secure loose objects, check drains and gutters are clear and move cars under cover or away from trees.
Meanwhile, MetService has a heavy rain watch in place for Coromandel Peninsula, Gisborne, and Hawke's Bay until Tuesday afternoon.
A strong wind watch was also in place for Taranaki, Nelson, Buller and Marlborough west of Wairau Valley, but excluding the Sounds, until Tuesday afternoon, and for Wellington and Marlborough Sounds until Monday night.
Snowy conditions down south
Waka Kotahi crews will be patrolling southern alpine highways as people travel home from the long weekend in snowy conditions.
Parts of the South Island have received several centimetres of snow overnight and icy conditions are expected to continue on Monday.
MetService's road snowfall warnings over Sunday night for Lewis Pass (SH7), Arthur's Pass (SH73), Porters Pass (SH73) have already lapsed.
Waka Kotahi South Island journey manager Tresca Forrester said crews were out monitoring the state highways and alpine passes 24/7.
"We put down chemical compound which helps where ice is forming on the highway, some areas where it is iced already we'll be putting grits down," Forrester said.
"But obviously if it's starting to turn and get a bit dangerous, our crews will close the road."
People should carry chains and travel during daylight hours if they were planning on using Porters Pass, Burkes Pass, Lindis Pass, Lewis Pass or Arthur's Pass, Forrester said.
"We're expecting extra people on the road, be prepared for extra traffic and potentially if you are travelling in some of those snow-affected areas, there could be a closure which may catch you up."
Mount Hutt was waiting to see if the wintry blast would be enough to open as planned for its 50th ski season on Friday.
The cold snap has dumped more than 10 centimetres of snow on the mountain, and staff have been able to get snow machines up and running for the first time this winter.
But field ski manager James McKenzie said they might still have to push out the date if the forecast weakened further.
"We didn't have anything really on the ground before this southerly came through, so it's quite nice to see the mountain changing to a bit more of a winter playground, but there's a reasonable way to go because we've only got sort of the first 10cm on the ground and we need a bit more than that to get it opened," McKenzie said.
"A week or so ago, it looked like it was going to be a phenomenally useful storm, with over a metre of snow forecast but everyday that we were closer to this weekend, those numbers dropped back," he said.
"I would be happy with 15-20 cm of snow and working with our snow bank system to get the rest of what we need to get our main trails open."
The opening date was a goal and subject to change - last year's opening date was moved back by 10 days, McKenzie said.
Prior to the snowfall, North Otago Federated Farmers president Myfanwy Alexander said farmers would be keeping their stock warm and dry in preparation.
Most South Island farmers had a plan for extreme cold weather in winter because of how frequent it could be, Alexander said.
