Thunderstorm Outlook
Issued at 6:54am 15/08/2026
Valid from 6:54am 15/08/2026 to Midnight 15/08/2026
A large low northeast of Bay of Plenty moves slowly southeast during the day. Showers are likely to develop about the west of the North Island this afternoon and there is a low risk of thunderstorms about Waikato, Waitomo, Taumarunui, western Taihape and inland areas of Taranaki and Whanganui this afternoon and evening. Elsewhere, the risk of severe convection or thunderstorms is minimal.
Issued at 10:11am 15/08/2026
Valid from Midnight 15/08/2026 to Midday 16/08/2026
There is minimal risk of thunderstorms or significant convection during this period.
Issued at 10:13am 15/08/2026
Valid from Midday 16/08/2026 to Midnight 16/08/2026
A front moving north, crosses the North Island during the afternoon and evening. There is a low risk of thunderstorms for Northland and northern parts of Auckland and Coromandel Peninsula from mid-afternoon through to the evening. Elsewhere, there is minimal risk of severe convection or thunderstorms.
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.
