Thunderstorm Outlook
Issued at 7:12am 7/09/2026
Valid from 7:12am 7/09/2026 to Midnight 7/09/2026
A low and associated fronts are expected to move eastwards across central and northern North Island today. A generally low risk of thunderstorms spreads eastwards this morning and afternoon for areas from Northland south to Taranaki, Taumarunui, Taupo, Bay of Plenty and northern Gisborne/Tairawhiti. This morning the risk of thunderstorms increases to moderate for a time about northern Northland. These thunderstorms may bring localised heavy rain with intensities of 10 to 25 mm per hour. During the afternoon and evening, the risk of thunderstorms is moderate for Waitomo, Waikato, southern Auckland, southern Coromandel Peninsula and Bay of Plenty. These thunderstorms may be accompanied by localised heavy rain with intensities of 10 to 25 mm per hour and small hail. Elsewhere, the risk of severe convection or thunderstorms is minimal.
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.
