Issued at 7:36pm 4/09/2026

Valid from 7:36pm 4/09/2026 to Midnight 4/09/2026

Update Friday evening at 7:30pm to extend moderate risk of thunderstorms for Fiordland, Westland and Buller into evening. From Buller to Fiordland, and also Southland, Stewart Island, Clutha and Dunedin, there is a moderate risk of thunderstorms bringing a risk of rain with intensities of 10 to 15 mm/h, strong wind gusts of 90 to 100 km/h, and hail of 5 to 15 mm diameter. Note, the risk of thunderstorms in these areas should decrease to low from Buller to central Fiordland later this evening, and about southern Fiordland, Southland, Stewart Island, Clutha and Dunedin tonight. There is a lower risk of thunderstorms in remaining western areas of the South Island, including the main divide, and North Otago until his evening. No thunderstorms or significant convection expected elsewhere during this period.

Issued at 8:29pm 4/09/2026

Valid from Midnight 4/09/2026 to Midday 5/09/2026

An unstable westerly flow affects the South Island during Saturday morning. There is a moderate risk of thunderstorms about Fiordland and Stewart Island before dawn and during the morning, and about southern and central Westland, including the main divide, during the morning. These thunderstorms if they occur are likely to bring localised heavy rain of 10 to 20 mm/h, small hail, and winds gusting 90 to 100 km/h. A lower risk of thunderstorms extends north to the Grey District and to western and southern areas of Southland. No thunderstorms or significant convection expected in other areas of New Zealand during this period.

Issued at 10:35am 4/09/2026

Valid from Midday 5/09/2026 to Midnight 5/09/2026

The unstable westerly flow continues to affect the South Island during the second half of Friday. There is a moderate risk of thunderstorms during the afternoon about central and southern Westland, including the main divide, and in the northern half of Fiordland; and during the afternoon and evening in the southern half of Fiordland, Southland and Clutha. These thunderstorms if they occur are likely to bring localised heavy rain of 10 to 20 mm/h, small hail, and winds gusting 90 to 100 km/h. A lower risk of thunderstorms extends to northern Westland, Buller and Dunedin. No thunderstorms or significant convection expected in other areas of New Zealand during this period.