Thunderstorm Outlook
Issued at 7:45am 13/08/2025
Valid from 7:45am 13/08/2025 to Midnight 13/08/2025
The combination of daytime heating, onshore breezes and cold temperatures aloft are expected to produce a few showers about the northwest of Northland this afternoon and early evening. There is a low risk of one or two of these developing into brief thunderstorms. No thunderstorms or significant convection expected over the remainder of New Zealand.
Issued at 7:37pm 13/08/2025
Valid from Midnight 13/08/2025 to Midday 14/08/2025
There is minimal risk of thunderstorms or significant convection during this period. Reviewed at 7:35pm Wednesday - no changes.
Issued at 8:31am 13/08/2025
Valid from Midday 14/08/2025 to Midnight 14/08/2025
There is minimal risk of thunderstorms or significant convection during this period. Afternoon and evening wind convergence's and cold temperatures aloft may produce a few heavy showers across Northland, however thunderstorms are not expected.
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.
