Thunderstorm Outlook
Issued at 7:48am 4/04/2026
Valid from 7:48am 4/04/2026 to 1:00am 5/04/2026
A front and associated rain-band moves slowly northwards through Fiordland and Westland today. Heavy Rain Warnings and Watches are in force for the Westland ranges and Canterbury headwaters - for more detail, see https://www.metservice.com/warnings/home. There is an associated low risk of thunderstorms embedded within the rain-band over northern Fiordland and southern/central Westland through into this afternoon, and a low risk about and offshore northern Westland from this evening. There is a minimal risk of thunderstorms or significant convection over other parts of New Zealand today.
Issued at 7:11pm 4/04/2026
Valid from 1:00am 5/04/2026 to Midday 5/04/2026
A front and associated rain-band lies slow-moving over Westland on Sunday morning. There is a low risk of a few thunderstorms embedded within the rain-band over parts of Grey and northern Westland districts before dawn. There is a minimal risk of thunderstorms or significant convection over other parts of New Zealand on Sunday morning.
Issued at 7:12pm 4/04/2026
Valid from Midday 5/04/2026 to Midnight 5/04/2026
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.
