"If Auckland is getting reports of snow flurries now at the warmest point of the day that makes you wonder about what might be coming tonight.
"There could be some snow flurries in Queen Street, but it won't settle."
Mr Duncan said 'graupel' - a soft hail that resembles snow - along with hail and sleet were also falling across the city.
He said snow would settle at heights of 200m and fall to 100m in Auckland overnight.
The storm was a 'once in a lifetime' event and similar conditions had not been seen in the city since the 1930s, he said.
Meanwhile, snowfall is being reported in downtown Wellington.
Twitter users reported heavy falls in Newton, while Parliament workers have confirmed snowfall at the Beehive.
The bitterly cold southerly blast has now brought snow to most of New Zealand, closing roads, some airports and cutting power to thousands.
Snow has made roads impassable in many areas of both islands.
MetService head forecaster Peter Kreft told NZPA the polar blast was "of the order of a 50 year'' event and warned it could last for several more days.
"It's a once in many decades event. We are probably looking at something like - in terms of extent and severity, maybe 50 years,'' he said.
The level of snow that fell in Wellington had not been seen since at least the 1970s, he said.
The front was bringing snow to parts of the country which did not usually see it and even Auckland would not be spared.
"I'd be surprised if over the next few days people didn't see sleet [in Auckland],'' he said.
NZ Post warned mail deliveries would be delayed in many areas because of the snow.
Animals in the snow
Christchurch's Orana Zoo is closed to the public because of the snow, but if it were open there would not be much for people to see.
"Ninety-nine per cent of the animals are inside," animal collection manager Ian Adams said.
"I wouldn't have thought many are enjoying the cold, they usually come out and play when it is sunny.
"We haven't had much snow, probably just two to three inches. The wind chill is the issue, it's much colder than usually."
Mr Adams said the key when the temperature dips was to keep the animals well fed and sheltered.
Animals at Wellington Zoo have also been confronting the cold.
Meanwhile Federated Farmers are not expecting the polar blast to adversely affect livestock.
Adverse events spokesperson David Rose said farmers had received plenty of notice from MetService to move vulnerable stock into sheltered paddocks and into yards.
"The MetService is also forecasting a number of good weather days towards week's end, so the light is appearing at the end of the tunnel.
"The only note of concern is from areas where snow is a complete rarity, like the Waikato. Dairy farmers couldn't believe their eyes this morning that they were milking in snowfall. Being in a 'warmer' part of New Zealand, lambing is underway there.
"That said, in the Bay of Plenty, farmers are mostly reporting a light dusting of snow and lambing is really just beginning up there. Certainly, there are no real issues for livestock and it's a similar picture in Auckland and Northland.
"While there are pockets of lambing underway in Canterbury, for the cooler regions of New Zealand or those at elevation, full scale lambing is still several weeks away.
Mr Rose said lambing does not begin in Southland until September and the High Country until October.
"Lambs and calves are incredibly robust. Even if it's cold for us humans, it takes just a few days of settled weather for them to find their feet."
Strong winds in Auckland cause injuries
Strong winds are also buffeting the north of the country, causing injuries to a number of people in Auckland city.
Four people have been taken to Middlemore Hospital after a tree fell on their home in Pakuranga Heights, Auckland this morning.
St John duty operations manager Patsy Carlyle said the mother and her two children received minor injuries, while an older man at the same address received moderate head injuries.
St John was called out to another weather-related incident at 7am this morning when ambulance officers tended a man in his 70s who had been blown against a pole at Grafton, moderately injuring his arm and leg.
He was taken to Auckland Hospital.
Fire Service crews in the northern half of the North Island have had a busy morning, with around 50 weather-related callouts between 8am and 9am.
Incidents ranged from downed trees and power lines to roofs being lifted due to high winds.
"It just went nuts for a period there," spokesman Colin Underdown said. "It's all calmed down now."
Big snow shutdown
Snow has made road conditions impassable in many parts of both islands.
Dunedin woke this morning to between three and four centimetres snow in the central city with the northern motorway closed in both directions and the southern motorway only open to traffic coming in to the city, Senior Constable Ian Henderson told NZPA.
In other parts of the South Island State Highway 1 is closed from Dunedin to Gore, Dunedin to Palmerston and Kaikoura To Waipara. Many other roads were also closed.
Mr Henderson warned people to think twice before driving unless they had a four-wheel-drive and chains.
The Southern District Health Board has postponed elective surgery and outpatient appointments at Dunedin and Wakari Hospitals today.
Dunedin Airport was also closed this morning with about 150 passengers forced to stay there overnight after four flights were grounded.
The airport would remain closed until the weather improved and ice on the runway was able to melt, Dunedin Airport chief executive John McCall told Radio New Zealand.
Passengers were also left stranded in Queenstown Airport and a number have flights had been cancelled in and out of Christchurch Airport this morning.
Christchurch Airport advised people to check with their airline before going to the airport.
Many schools across the South Island were closed for the day.
'Stay at home' message to South Islanders
Christchurch police urged people to check conditions before travelling and drive to the conditions.
"We are asking the public to stay at home and delay all non-essential travel if they do not think they can travel safely in their local conditions,'' Inspector Al Stewart, Canterbury road policing manager said.
Canterbury University, Christchurch Polytechnic Institute of Technology, and Otago University's Christchurch campus had all been closed for the day and Environment Canterbury said all Christchurch metro bus services had been suspended until further notice.
Invercargill police said there had been some snow flurries overnight but rain had washed away most of the snow.
Southland Civil Defence was advising people to stay at home and avoid all non-essential travel this morning.
North Island roads affected
The main highways in and out of Hawke's Bay have been closed by snow as a result of the polar blast covering much of New Zealand.
The New Zealand Transport Agency reports State Highway 5 Napier To Taupo Road is closed due to snow along with State Highway 2 Norsewood - Waipukurau and State Highway 2 Gisborne To Nuhaka Road. State Highway 2 from Dannevirke To Norsewood is also closed.
It is unclear when the roads will reopen.
Snow has also fallen in many parts of the North Island including in and around Wellington.
Many hill roads around the capital were closed this morning, including the Rimutaka Hill Road. The Desert Road and the alternate route through National Park in the central North Island were also closed.
Power cuts in lower North Island, parts of Christchurch
High winds and snow caused trees and branches to tear down power lines cutting power to about 6000 customers across the lower North Island overnight and this morning.
"Supply is being progressively restored to customers and there are currently around 4000 properties without supply, the majority of those being in South Taranaki with a few in rural Wanganui, Manawatu and Wairarapa,'' Powerco Network operations manager Phil Marsh said.
Mr Marsh said Powerco expected to restore supply to the majority of affected customers by the end of the day..
"Safety is our number one priority and it is likely that if the forecast severe weather deteriorates we will have to call our field staff off the job until it is safe for them to be back out on the roads,'' he said.
Snow cut power to a few hundred people in Christchurch and central Canterbury overnight, lines company Orion said.
Crews were working as "fast as possible'' to restore power to parts of Sumner, Tai Tapu and Springston, Orion manager Rob Jamieson said.
"In general the network is coping pretty well, with fewer issues at this stage than we experienced during the July snow storm.
"However, it's likely to be a longer event this time, and our crews are ready to respond quickly to any further issues and make any repairs needed,'' Mr Jamieson said.
Snow in unusual places
Snow had settled in Wanganui for the first time since 1974, Constable Simon Beswarick told NZPA.
Worse weather is predicted for the North Island - including Auckland - today.
Last night, rescuers finally managed to free 100 people who had been trapped in their vehicles on the Rimutaka Hill Rd, between Wellington and Wairarapa.
Inspector Mike Coleman of police communications said officers had earlier urged people "to stay in their vehicles rather than get out and walk".
Emergency services used a four- wheel-drive vehicle and a snow plough to clear the road and rescue the motorists by 9pm. Other drivers were still trapped in parts of the Wairarapa.
Auckland snow forecast
Today, Auckland will have its turn. Snow is forecast to fall and possibly settle on the tops of the Waitakere and Hunua ranges and the peaks of the Coromandel Peninsula.
WeatherWatch chief analyst Philip Duncan said the polar outbreak was unlike anything he had seen.
"I've been watching the weather closely for about 15 years and I've never seen a prediction like this."
A large high stretching from the Antarctic to the sub-tropics had merged with three low-pressure systems to create the unusual weather.
He predicted snow to 200m above sea level in Auckland this morning.
"It doesn't mean that it's going to sit up there and snow all day, it just means that as the turbulent showers come through, they can drop snow," Mr Duncan said. "So we'll see it snow to about 200 metres and we'll get sleet below that."
He said Auckland could expect a maximum temperature of 10C today and 9C tomorrow.
The city's lowest recorded daily maximum is 7.8C.
Wellington's 'snowmageddon'
The snowfall in Wellington caused excitement and chaos throughout the city last night. Snow settled in the northern suburbs, including Churton Park, Newlands and Karori, and there was flooding in Kilbirnie.
The final of the Ford National Hockey League was called off mid-game because of the weather.
English actor Stephen Fry, who is in Wellington filming The Hobbit, was among hundreds of people who took to Twitter.
"It's been an exciting day here in Wellington. Snow. That's unusual ... NZ is same latitude as Melbourne so it's rare," Fry tweeted.
Another person described it as "snowmageddon".
"In wellington playing in the SNOW!!! theres so much of it!! yee snow fights and snow men!," said Kelsey Pilbrow.
Thomas Beagle, from the inner Wellington suburb of Northland, told the Herald he had never seen anything like it in the 40 years he had been in the city.
"It's really incredible. Everyone's very excited about it and getting out there ... I think they're hoping for more snow tomorrow so they don't have to go to work."
THE OUTLOOK
Today
* Snow expected to fall in Auckland region peaks. Maximum high of 10C.
* More snow for Wellington, Wanganui, Palmerston North, Napier and Hastings regions.
* More heavy snow expected in the South Island, with Queenstown dropping to minus 4C.
Tomorrow
* Auckland's maximum temperature expected to be 9C.
* Heavy showers forecast for much of the North Island.
* More heavy snow in the South Island and lower North Island.
* The polar outbreak will start to move from the north of New Zealand.
- additional reporting NZPA
