Thunderstorm Outlook
Issued at 7:25am 5/08/2026
Valid from 7:25am 5/08/2026 to Midnight 5/08/2026
There is minimal risk of thunderstorms or significant convection during this period. Although not indicated on the chart, wintry showers with hail expected about the Chatham Islands during the day, with a low risk of thunderstorms during the evening and night.
Issued at 8:54am 5/08/2026
Valid from Midnight 5/08/2026 to Midday 6/08/2026
There is minimal risk of thunderstorms or significant convection 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.
