Issued at 5:48pm 21/09/2026

Valid from 5:48pm 21/09/2026 to Midnight 21/09/2026

A front is moving northwards across the lower South Island this evening, bringing rain to Fiordland and Westland, along with a moderate risk of thunderstorms over northern Fiordland and southern Westland as depicted on the chart. These thunderstorms may produce localised rainfall rates of 10 to 20 mm/h. No thunderstorms or severe convection expected elsewhere during this period.

Issued at 7:29pm 21/09/2026

Valid from Midnight 21/09/2026 to Midday 22/09/2026

A front moves onto the far south of the South Island late Tuesday morning with significant cooling aloft. There is a low risk of thunderstorms for Fiordland and Stewart Island and southern Southland. The risk of thunderstorms is considered moderate however, from mid to late morning for much of Fiordland and Stewart Island with the front. These thunderstorms may be accompanied by heavy rain 10 to 15 mm/h and small hail. There is minimal risk of thunderstorms or significant convection elsewhere during this period.

Issued at 10:15am 21/09/2026

Valid from Midday 22/09/2026 to Midnight 22/09/2026

The front moves northwards over the South Island during the second half of Tuesday. There is a moderate risk of thunderstorms for Fiordland and southern Westland during the afternoon, with a low risk extending further north up the west coast of the island as the front moves north as indicated on the chart. There is also a moderate risk of thunderstorms for central and southern Southland, Stewart Island, Clutha and much of Dunedin during the afternoon, reducing to low in the evening. A low risk of thunderstorms also extends further north through northern Southland, Central and North Otago and the Canterbury coast and Plains from Christchurch southwards during the afternoon and evening. This low risk may also extend into the night about Banks Peninsula. These thunderstorms if they occur may be accompanied by strong wind gusts 80 to 100 km/h, heavy rain 5 to 15 mm/h and small hail. There is minimal risk of thunderstorms or significant convection elsewhere during this period.