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Thunderstorm Outlook

Issued at 8:17am 11/04/2026

Valid from 8:17am 11/04/2026 to Midnight 11/04/2026

Cyclone Vaianu is expected to be approaching the northern North Island this evening. There are many Watches and Warnings in place for severe gale winds and and heavy rain - refer to https://www.metservice.com/warnings/home for more details. A rainband south of the cyclone is expected to affect Gisborne/Tairawhiti and Mahia Peninsula from the afternoon and there is a low risk of thunderstorms producing heavy rain. A low risk of thunderstorms develops about Northland, northern Auckland and Coromandel Peninsula from evening. Elsewhere, the risk of significant convection or thunderstorms is minimal.

Thunderstorm Outlook for New Zealand

Issued at 8:15pm 11/04/2026

Valid from Midnight 11/04/2026 to Midday 12/04/2026

Chart reviewed at 8:10pm Saturday and moderate risk of downpours extended to western Bay of Plenty. Cyclone Vaianu is expected to move onto the northern North Island during Sunday morning. There are many Watches and Warnings in place for severe gale winds and and heavy rain - refer to https://www.metservice.com/warnings/home for more details. An active rainband associated with the cyclone is expected to move onto the North Island during Sunday morning and there is a low risk of thunderstorms producing heavy rain in the west from Northland to Taranaki, also Coromandel Peninsula, Bay of Plenty and Gisborne/Tairawhiti as depicted on the chart. Also, there is also a low risk of localised downpours for Northland and northern Auckland, but moderate risk for Coromandel Peninsula and western Bay of Plenty, which is associated with the convective bands close to the cyclone centre during the morning with rainfall rates of 25 to 40 mm/hr. A low risk of thunderstorms develops about Fiordland as a front in the Tasman Sea moves onto the southern South Island during the morning. Elsewhere, the risk of significant convection or thunderstorms is minimal.

Thunderstorm Outlook for New Zealand

Issued at 11:15am 11/04/2026

Valid from Midday 12/04/2026 to Midnight 12/04/2026

Cyclone Vaianu is expected to move across the central North Island during Sunday afternoon and evening. There are many Watches and Warnings in place for severe gale winds and and heavy rain - refer to https://www.metservice.com/warnings/home for more details. Several active active rainbands associated with the cyclone are expected to move across the central New Zealand during Sunday afternoon and evening and there is a low risk of thunderstorms and localised downpours for much of the North Island south of Auckland including Marlborough as depicted on the chart. However, there is a moderate risk of localised downpours for Coromandel Peninsula, Bay of Plenty including Rotorua and northern Gisborne/Tairawhiti during the afternoon with rainfall intensities of 25 to 40 mm/hr. There is also a residual low risk of thunderstorms about Fiordland with an weakening from in the afternoon. Elsewhere, the risk of significant convection or thunderstorms is minimal.

Thunderstorm Outlook for 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.