A cold front, preceded by strong northwesterlies, is expected to approach Fiordland from the south Tasman Sea today (Tuesday), then move northeast over the South Island during Wednesday and early Thursday before weakening. A Heavy Rain Warning is now in force for much of Fiordland and Westland from Moeraki southwards, and a Heavy Rain Watch is in place for the ranges of Westland between Otira and Moeraki.
Just an update on the current Heavy Rain Warning in place for Fiordland.

There is now a Strong Wind Warning in place for Southland, Fiordland and Stewart Island.

Heavy Rain Warning for Fiordland – Orange
Heavy rain may cause streams and rivers to rise rapidly. Surface flooding and slips are also possible and driving conditions may be hazardous.

Issued: 8:42pm Tuesday, 26th January 2021
Area: Fiordland north of Dusky Sound
Valid: 11:00am Wednesday to 7:00pm Wednesday
Expect 70 to 100mm of rain to accumulate. Peak rates of 20 to 30mm/h.
Strong Wind Warning for Southland, Fiordland, Stewart Island – Orange
Strong wind gusts could damage trees, powerlines and unsecured structures. Driving may be hazardous, especially for high-sided vehicles and motorcycles.

Issued: 8:42pm Tuesday, 26th January 2021
Area: Fiordland, Southland including Stewart Island
Valid: 9:00pm Tuesday to 6:00pm Wednesday
North to northwest gales are forecast to be severe at times, with gusts reaching 120 to 130km/h in exposed places.

For more information head to https://www.metservice.com/warnings/home#severe-weather-warnings-and-watches

For more information on how to prepare head to https://getready.govt.nz/emergency/storms/