UPDATE: Cyclone Gita to potentially bring 7.5 metre waves, snowfall in onslaught set for Tuesday

Cyclone Gita is continuing a path that forecasters expect will bring it crashing into New Zealand on tomorrow or Wednesday, unleashing heavy rain and possibly snowfall.

Having caused damage to Tonga last week, the cyclone is taking a boomerang-shaped path that has it currently lying south of New Caledonia, according to MetService's latest tracking map today.

It is expected to soon begin its turn back towards New Zealand and approach from the northwest as it transforms into an extra-tropical cyclone, MetService says.

Check the forecast in your region on the 1 NEWS NOW weather page

Metservice has issued a severe weather warning for Cyclone Gita to bring damaging winds and heavy rain to parts of central New Zealand on Tuesday and Wednesday.

Cyclone Gita, currently located over the Tasman Sea, is forecast to track southeastwards and cross central New Zealand late Tuesday and early Wednesday.

The passage of Gita is expected to bring a period of high-impact severe weather to many parts of central New Zealand. 

Heavy rain will cause slips, rapidly rising streams and rivers, and flooding. 

Severe gales with damaging gusts are expected, so people are advised to secure property and items that may be blown away by strong winds. 

There is also the potential for coastal inundation with high tide overnight Tuesday and before dawn on Wednesday, due to the combination of tides, low air-pressure, strong onshore winds and large waves in excess of six metres in some places. 

For the North Island, coastal areas from Raglan southwards to southern Wairarapa are most at risk. 

For the South Island, the risk of coastal inundation is greatest for areas from Buller and North Canterbury northwards. 

In a live update on Facebook at 2.30pm, senior meteorologist Lisa Murray said the latest map shows the heaviest rain will be over the Wellington region, southern Wairarapa, Nelson, Buller, Marlborough, the Kaikoura coast, Canterbury plains and high country and along Westland including the ranges.

She also said that with strong wind, some places could see 7.5 metre swells affecting the coast, including in Nelson and Marlborough, Buller, Kapiti and northern Wellington.

Keep up to date with MetService's latest warnings.

Cold air being dragged northwards by the cyclone may lead to snow falling to unseasonably low levels about the Canterbury high country on Tuesday.

It is unlikely the snow will warrant a widespread snow warning, but it may still affect some of the alpine roads in Canterbury.

CIVIL DEFENCE: PREPARE NOW AND BEHAVE SENSIBLY DURING THE STORM

The Ministry of Civil Defence and Emergency Management is advising people to prepare for the possibility of power cuts, water outages and road closures.

Ministry of Civil Defence Director Sarah Stuart-Black yesterday said it's a good idea to have a grab bag ready in case you need to evacuate.

Non-essential travel during the storm is strongly discouraged, as roads will be especially dangerous.

Items which could be blown around by wind should be tied down and secured, including items like trampolines.

During the storm, close windows and curtains and avoid potential injury from breaking glass.

Bring your pets inside, and if you are forced to leave your home, be prepared to take them with you.

Marlborough warnings

Marlborough Civil Defence says anyone in the Marlborough Sounds, especially campers, trampers and boaties should leave the area today. Hunters and trampers in the high country should also keep an eye on rapidly rising rivers.

Marlborough Civil Defence says there's a heavy rain warning from 10am to 10pm Tuesday when 150 to 200mm of rain around higher ground and lesser amounts elsewhere is expected. Peak intensities of 20 to 30mm/hr are possible 

And there's a strong wind warning from 4pm Tuesday to 4am Wednesday for severe gale southeasterlies gusting 130 km/h in exposed places.

Be aware of fast rising streams and river levels. Expect coastal impacts with high tide overnight Tuesday and before dawn on Wednesday, due to the combination of tides, low air pressure, strong onshore winds and large waves in excess of six metres in some places.

Road closures from high river levels are possible at the Pelorus across SH6, Wakamarina Rd, Queen Charlotte track at Havelock, SH1 beside the Para Swamp and SH63 Wairau Valley. 

Boaties should be aware of debris at sea over the next few days.

Grey District schools to close

Grey District Council says all schools, early childhood centres and the Polytech will be closed on Tuesday and Wednesday.

Cyclone Gita, currently over the North Tasman Sea, is forecast to affect the West Coast overnight tonight, tomorrow and Wednesday. 

The council says this is a significant storm with potential for severe gale-force winds, dangerous storm surges and waves causing coastal inundation and flooding, and heavy rain causing rapidly rising streams and rivers, causing flooding.