Photo: MetService
MetService has issued heavy rain warnings for parts of the West Coast, and a heavy rain watch for the Tararuas and Tasman.
A front is slow-moving over the northwest of the South Island through to Sunday afternoon. A moist northwest flow ahead of this front brings periods of heavy rain to western areas of the South Island and the Tararua Range.
There is a heavy rain warning (orange) for Buller until 4pm Sunday and for the ranges of Westland about and north of Harihari until 3pm Sunday.
MetService said there would be periods of heavy rain and possible thunderstorms over Saturday, where amounts may approach warning criteria.
More significant heavy rain is predicted from Saturday night through to Sunday evening, with 120-160 mm of rain expected in Buller, and 90-130mm of rain for the ranges of Westland, peaking at 15 to 25 mm/hr.
The forecaster warned that heavy rain may cause streams and rivers to rise rapidly. Surface flooding and slips were also possible and driving conditions may be hazardous.
There are heavy rain watches in place for the Tararua ranges until 2am Sunday and for Tasman, west of Takaka, until 5pm Sunday. Amounts may approach warning criteria, according to MetService.