Thunderstorm Outlook
Issued at 7:34pm 7/08/2026
Valid from 7:34pm 7/08/2026 to Midnight 8/08/2026
The slow-moving front continues to affect the west of the upper South Island. During the afternoon and evening, there is an associated low risk of thunderstorms for coastal areas of the western Tasman District, and the districts of Buller, Grey and central and northern Westland. Cold showery conditions over Fiordland ease during the afternoon, and there is a low risk of thunderstorms in Fiordland during the afternoon and evening. There is minimal risk of thunderstorms or significant convection elsewhere in New Zealand during this period.
Severe Thunderstorm Criteria
In New Zealand, MetService classifies a thunderstorm as severe if one or more of the following criteria are met:
Heavy rain (from thunderstorms):
Rainfall of 25mm/h, or more.
Large hail:
Hailstones 20mm in diameter, or larger.
Strong wind gusts (from thunderstorms):
Gusts of 110km/h (60 knots) or stronger.
Damaging tornadoes:
Fujita F1 - i.e. wind speeds greater than 116km/h (63 knots) or stronger.
Note: some tornadic systems such as funnel clouds, waterspouts and small land-based tornadoes are possible with thunderstorms that may not be classified as severe.
