Parts of the South Island are in for a lashing today

MetService has issued a heavy rain watch for parts of Fiordland and the far south of Westland from 2pm until Friday morning.

Meanwhile, it's predicting very warm conditions for eastern New Zealand in coming days, with temperatures rising into the 30s from Friday through the weekend

Meteorologist Thapi Makgabutlane says thunderstorms are possible in parts of Fiordland and south Westland tonight.

She says on top of recent heavy rain, intense downpours may cause flooding and make driving dangerous.