Heavy rain and possible thunderstorms are possible for today, with the MetService issuing a severe weather warning for the region.

Heavy rain is expected to spread through the area today.

The MetService predicted about 100 to 140mm of rain to fall from 10pm Thursday until 10pm tonight.

The rain is expected to spread down the country, arriving in Christchurch early Saturday and should bring some help there with the fires on the Port Hills.

'There is still some uncertainty with rainfall amounts for the Christchurch region on Saturday,” says forecaster Cameron Coutts, 'but up to 10mm is possible.”

Low-pressure drags moist east to northeasterly wind across NZ on Friday. Rainy in the North & upper South https://t.co/Yjbq0jfCz1 ^CL pic.twitter.com/b22e4uWxi7

— MetService (@MetService) February 16, 2017

There are many events on over the country this weekend, with those in the south of the South Island, such as the Challenge Wanaka triathlon, looking fine.

Unfortunately, rain, showers and thunderstorms over the North Island and northeast of the South Island through Friday and into Saturday will have a significant effect on events elsewhere.

'Some of the falls could be heavy over the North Island, with the risk of downpours and localised flooding,” says Coutts, 'so keep an eye on the latest forecasts and the MetService rain radars.”