MetService has issued a severe weather warning for Fiordland, Westland, Canterbury and Nelson today.
They report that an active front is expected to move eastwards across the South Island today, preceded by strong northerlies and a period of heavy rain for the West Coast and Alps.
The heaviest falls are expected in the ranges of Westland where 180mm of rain may fall, and in Fiordland north of about Milford Sound and the ranges of northwest Nelson with 80mm possible.
Significant spillover rain is also expected for the headwaters of the Canterbury lakes and rivers.
Behind this front, further rain or heavy showers are likely but at lesser intensities.