A tropically-fuelled low packed with rain was starting to unleash on the top half of the North Island this morning, while flood-ravaged parts at the top of the South Island are set for another round of intense downpours, and a polar blast bringing widespread snow.
MetService warned of a stark and sharp change in store today, with temperatures in the south taking a dive, coupled with wet weather as a cold front sweeps up the island.
The mercury is set to plunge across the mainland to freezing by the end of today, with southerly winds bringing rain and frigid air from Antarctica - starting in Southland in the morning and reaching Canterbury after lunch.
MetService said Gore and Invercargill were forecast to reach their maximum of 13degC by 1am, Dunedin would have a high of 15degC and a low of just 4degC, Queenstown a high of 14degC and low of 3degC, while Christchurch was expected to drop from a balmy 23degC in early afternoon to a wintry 10degC by evening.
Snow for alpine roads
Snow is forecast to lower to 400 metres in parts of Canterbury, Otago and Southland and most alpine passes in the South Island were set to get some snow today and tomorrow, MetService advised.
Crown Range Road: from 5pm until 9pm on Thursday snow flurries may affect the road linking Queenstown and Wanaka, but little snow was expected to settle.
Lindis Pass (SH8): From 11pm on Thursday until 4am on Friday expect 1cm to 2cm to settle on the road.
Porters Pass (SH73): From 1am-11am on Friday snow was likely to affect the road, with 3cm to 5cm expected to settle.
Arthur's Pass (SH73): From 3am-8am on Friday snow was likely to affect the road, with 2cm to 4cm expected to settle.
Lewis Pass (State Highway 7) : From 8am-12pm on Friday some snow flurries may affect the road in the morning and up to 2cm may settle on the road.
Heavy rain warnings
Heavy rain warnings have been issued for western regions of the South Island and the bottom half of the North Island through to Mt Taranaki.
Up to 180mm is expected to fall in Kahurangi National Park at the top of the South Island, while rain forecast for the Tararua Range and Mt Taranaki may reach warning criteria when it starts falling after lunch today.
Those in affected central regions should watch for rapidly rising streams and rivers, potential slips and hazardous driving conditions.
Warnings and watches also now include northern regions including Auckland, Northland, Coromandel Peninsula and Bay of Plenty. Heavy rain is forecast to fall for 24 hours from 3am on Saturday to 3am on Sunday.
"At this stage it looks like the heaviest rain will affect Auckland and Coromandel Peninsula and it is likely that a warning for those areas will be issued closer to the event," said the forecaster.
MetService said by Saturday, a low pressure system affecting the North Island would make for a rainy start to the school holidays while the South Island would have more settled weather.
- NZ Herald and ODT Online
