Thunderstorm Outlook
Issued at 7:51am 30/05/2026
Valid from 7:51am 30/05/2026 to Midnight 30/05/2026
There is minimal risk of thunderstorms or significant convection during this period.
Issued at 7:53pm 30/05/2026
Valid from Midnight 30/05/2026 to Midday 31/05/2026
Chart reviewed at 7:50pm Saturday and no changes made. A front moves overnight the South Island from the Tasman Sea and is preceded by a humid airmass. There is a low risk of elevated thunderstorms for parts of Fiordland and Westland as indicated on the chart from about dawn. Minimal risk of thunderstorms or significant convection for the remainder of New Zealand.
Issued at 9:29am 30/05/2026
Valid from Midday 31/05/2026 to Midnight 31/05/2026
An elevated thunderstorm risk has been assessed as low for western parts of the South Island from Fiordland to western Tasman District. Additionally, a front approaches the far north of Northland later in the day and there is a low risk of thunderstorms from evening. Minimal risk of thunderstorms or significant convection for the remainder of New Zealand.
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.
