Heavy rain, gales and possibly thunderstorms are forecast for parts of the South Island today.
MetService said rain may reach warning levels or up to 90mm in some places on the West Coast, but there's warm temperatures in the east.
Dunedin could reach a high of 21degC, Christchurch 22degC and Invercargill 20degC.
Driving this weather is a complex frontal system, preceded by a strong moist north to northwest flow, approaching the South Island before moving north across the island.
This system is expected to bring periods of heavy rain to the west and north of the South Island, and gale northwesterlies about Canterbury High Country, where warnings and watches are in force.
MetService said a trough in the upper atmosphere brings unstable conditions and there's a moderate risk of thunderstorms for Clutha and areas of Dunedin, south of Dunedin City.
Any thunderstorms that occur in these areas could bring localised heavy rainfall rates of 10mm to 20mm per hour.
On the West Coast, heavy rain warnings are in place for the ranges of Westland, about and north of Otira from 9am until 8pm today, with a further 50mm to 70mm of rain to accumulate on top of what has already fallen.
For Westland, south of Otira, up to 90mm of rain is expected about the ranges on top of what has already fallen, and 20 to 40mm near the coast until 4pm today.
For the headwaters of the Canterbury lakes and rivers, a further 60mm to 90mm may accumulate about the main divide on top of what has already fallen, and 40 to 60mm within 15km east of the divide.
Heavy rain may cause streams and rivers to rise rapidly. Surface flooding and slips are also possible and driving conditions may be hazardous.
A strong wind watch is also in place for the Canterbury High Country, as northwest winds may approach severe gale in exposed places at times until about 4pm today, MetService said.
Late tonight the rain was expected to spread from the West Coast to the North Island, reaching most western areas from Wellington to Auckland and Northland by the end of tomorrow, with scattered showers in the east.
On Tuesday the rain will shift to the northeast, stretching from Northland to Gisborne, as showers clear to the south.
MetService forecast Tuporo Marsters said those attending the Bledisloe match between the All Blacks and Australia in Wellington this afternoon might want to bring a raincoat with showers forecast, accompanied by strong northerlies.
- ODT Online and NZ Herald
