A cold front is expected to cross much of the South Island tomorrow morning and the MetService expects northwest winds to reach severe gale force briefly in Fiordland, Southland, Otago, and Canterbury.
"These winds have the potential to damage trees and powerlines, to lift roofs, and make driving hazardous, especially for motorcycles and high sided vehicles," the MetService website said.
There is also expected to be a burst of heavy rain tomorrow morning about Fiordland, and the ranges south of Otira. Although the amounts forecast are not large for the area, the intensity means streams and rivers could rise rapidly.
Between midnight tonight and 9am tomorrow, northwesterlies could reach 70 kmh at times in exposed places, with gusts of 130 kmh, especially about higher parts of Fiordland, and in inland Southland.
Between 3am and noon tomorrow in Otago and Canterbury northwesterlies could reach 65 kmh at times in exposed places - mainly inland - with gusts of 120 kmh.
In the six hours from midnight tonight to 6am tomorrow, Fiordland can expect 80-90mm of rain with intensities reaching 25mm per hour. The Westland ranges, south of Otitra will have the same intensities per hour but can expect 70-80mm in the six hours starting 3am in the south, and 6am in the north.