Thunderstorm Outlook
Issued at 7:54pm 3/08/2026
Valid from 7:54pm 3/08/2026 to Midnight 4/08/2026
A trough bringing showers moves northwards over Northland during Tuesday afternoon. There is an associated low risk of thunderstorms in the north and west of Northland, as indicated on the chart. Meanwhile, a cold and showery south to southwest flow becomes established over the southern and eastern North Island. From evening there is a low risk of thunderstorms near the coast of Hawke's Bay from Cape Kidnappers southwards, about Mahia Peninsula, and near the coast of Gisborne/Tairawhiti, as depicted on the chart. Lastly, a strong and cold southwesterly flow continues to bring wintry showers with hail to the Chatham Islands, along with a moderate risk of thunderstorms. 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.
