The South Island faces heavy rain in the west and gales in the south as a front moves tomorrow.
On Sunday the front, preceded by a strong, moist northwest wind, will move eastward on to the far south of the South Island. It will then head northeast over the South Island on Monday.
MetService said this will mean heavy rain for Fiordland, Westland, and the headwaters of the Otago lakes and rivers, as well as strong northwesterly winds to Fiordland, Southland, Stewart Island, and Clutha.
In addition, it warned that rainfall amounts are "unusually large for Fiordland (300-400mm)".
"Streams and rivers may rise rapidly and damage to trails and roads is possible," MetService added on Facebook.
Heavy Rain Warning - Orange
Impact: Heavy rain may cause streams and rivers to rise rapidly. Surface flooding and slips are also possible and driving conditions may be hazardous.
Area: Westland south of Ōtira
Period: 27hrs from 7pm Sun, 12 Nov - 10pm Mon, 13 Nov
Forecast: Expect 100 to 150 mm about the ranges north of the Glaciers and 200 to 250 mm of rain about the ranges farther south. Expect 70 to 140 mm nearer the coast, with the largest amounts about and south of the Glaciers. Peak rates of 15 to 20 mm/h about the ranges.
Area: Fiordland
Period: 31hrs from 8am Sun, 12 Nov - 3pm Mon, 13 Nov
Forecast: Expect 300 to 400 mm of rain, with the largest amounts about the fiords. Peak rates of 15 to 25 mm/h. Note that these rainfall amounts are unusually large, even for Fiordland. Streams and rivers are likely to rise rapidly and damage to trails and roads is possible.
Heavy Rain Watch
Area: Headwaters of the Otago lakes and rivers
Period: 31hrs from 11am Sun, 12 Nov - 6pm Mon, 13 Nov
Forecast: Periods of heavy rain. Rainfall amounts may exceed warning criteria within 30 km east of the main divide and it is likely that this watch will be upgraded to a warning closer to the event.
Strong Wind Watch
Area: Fiordland, Southland, Stewart Island and Clutha
Period: 13hrs from 1am - 2pm Sun, 12 Nov
Forecast: Northwest winds may approach severe gale in exposed places.
