A front over the Tasman Sea is expected to cross the South Island Saturday night and Sunday morning, preceded by a period of heavy rain and strong to gale northerlies. The heaviest falls are expected in Fiordland and the ranges of Westland south of Otira, where 100mm of rain is possible through to early Sunday morning. The Tararua Range is also likely to receive heavy rain early Sunday morning. Although this is not an unusual amount of rain for these areas, people are advised rivers and streams may rise rapidly, slips and surface flooding are possible.

In addition, severe northwest gales are likely over Wellington until about dawn and Wairarapa until mid-morning Sunday. Winds of this strength have the potential to damage trees and powerlines, and make driving hazardous.