It's a wet day for the South Island on Saturday as waves of wind and rain lash the north and west, with a moderate risk of thunderstorms for Westland and Fiordland.
As a big high-pressure system moves east of New Zealand it will pull down warm moist air from the sub-tropics, creating a "complex trough" in the Tasman Sea.
"A series of fronts are expected to move onto the South Island from the Tasman Sea this afternoon, then move onto the North Island during Sunday," MetService says on Facebook.
"These fronts, preceded by strong north to northwesterly winds, are forecast to bring periods of heavy rain to the west of the South Island, including the headwaters of the Otago and Canterbury lakes and rivers, also to the Tararua Range and Mount Taranaki. Heavy Rain Warnings and Watches are now in force for these areas.
"In addition, strong north to northwest winds could approach severe gale strength in exposed parts of Fiordland, Southern Lakes, Canterbury High Country, Marlborough, Wellington and Wairarapa, where Strong Wind Watches are in force."
While there will be little change in maximum temperatures for most on Saturday, as the subtropical air washes over the country it means warmer than average temperatures for most on Sunday.
"As warmer, wetter air washes over the country this weekend, maximum temperatures are set to rise," MetService says.
"Kaikoura, Timaru and Christchurch are set to beat their May averages by 10C tomorrow [Sunday]."
