The MetService is warning Aucklanders to batten down the hatches for one of the worst storms in recent years tomorrow.
MetService spokesman Peter Kreft says the storm is "one of the largest and deepest lows we've seen for some years."
The severe storm is expected to hit Auckland some time between midday Saturday and midday Sunday.
"By the time this system reaches northern New Zealand on Saturday, it is likely to have significant destructive potential," Mr Kreft says.
"The real issue will be the wind, with gusts of more than 110km/h expected."
The rapidly intensifying storm is expected to strike Northland first, then Auckland before reaching Bay of Plenty and Gisborne late Sunday, MetService said.
Far North District Council civil defence teams and contractors are on stand-by ready to deal with any fall-out from the storm.
Mr Duncan said: "It is going to deepen rapidly and has the potential of bringing damaging winds, flooding rains, big seas and strong rip tides. It may well be the most intense sub-tropical storm of the decade".
He said the air pressure with this system could drop to 967hPa for a time on Saturday which he says is extremely rare for areas near Auckland.
"This could help create one of the biggest storm surges seen in the upper North Island for several years," he said.
"If this prediction eventuates we could see storm surges flooding low lying eastern coastal areas from Northland to Auckland and across Coromandel and Bay of Plenty. It may also pose a serious risk for low lying areas around the Firth of Thames which is particularly vulnerable to northern storm surges".
This morning, Cook Strait ferries were cancelled after swells of up to four metres.
The MetService has issued a storm warning for the area and the Interislander has cancelled two sailings out of Wellington and one from Picton.
The current storm is forecast to subside this afternoon and afternoon sailings have been scheduled to sail on time.
Meanwhile further south, the heavy snow falls forecast yesterday are no longer expected.
Forecasters are predicting light snow showers down to 300 metres above sea level in the foothills north of Methven and around the Banks Peninsula in the South Island.
The good news on the rain front for the weekend is that, while it is expected to be heavy, it should be short.
"The real issue will be the wind," with gusts of more than 110km/h expected, Mr Kreft.
A low is crossing the north Tasman Sea today and is expected to deepen rapidly as it approaches northern New Zealand Saturday morning.
The unusually intense low is forecast to move over Cape Reinga late Saturday afternoon then track southeastwards to lie near the Coromandel Peninsula at midnight and near East Cape midday Sunday.
A front ahead of the low is expected to bring widespread rain to the North Island by the end of Saturday and gales are likely to affect most parts of the North Island.
The heaviest rain should be in Northland, northern Auckland, the Coromandel Peninsula, Gisborne and Hawkes Bay ranges and these areas streams and rivers could rise quickly along with some surface flooding.
East to southeast gales may affect many parts of the North Island with strongest winds gusting to around 120 km/h in parts of Northland, Auckland,Coromandel Peninsula, Waikato, eastern Bay of Plenty, Gisborne, the central North Island,Manawatu and Wellington.
MetService advises the public that winds of this strength have the potential to cause damage and make driving hazardous.Boaties are advised to make moorings secure as high winds and large waves are likely about northern and eastern coasts of the North Island.
- NZ HERALD STAFF, NZPA