Thunderstorm Outlook
Issued at 7:37am 8/07/2026
Valid from 7:37am 8/07/2026 to Midnight 8/07/2026
A low northeast of the upper North Island moves slowly away to the northeast. A front moves north along the east of the North Island during Wednesday afternoon and evening. This morning, there's a low risk of thunderstorms near the east coast of Coromandel Peninsula and Great Barrier Island, before the low moves eastwards. Along the east coast from Wairarapa to East Cape, there is also a low risk this morning, continuing into the evening about the Wairarapa and Hawke's Bay coast, but easing about the Gisborne coast this afternoon. Elsewhere over New Zealand, there is minimal risk of thunderstorms or significant convection during this period.
Issued at 7:39pm 8/07/2026
Valid from Midnight 8/07/2026 to Midday 9/07/2026
Overnight and during Thursday morning, a trough moves northwards across Northland, bringing showers especially to western parts. There is a low risk of thunderstorms, as indicated on the chart. Rain will affect the east coast of the North Island as a cold southerly flow spreads northwards, and there is a low risk of thunderstorms for coastal Hawke's Bay and Gisborne about and south of Tolaga Bay. There is minimal risk of thunderstorms or significant convection elsewhere during this period.
Issued at 9:31am 8/07/2026
Valid from Midday 9/07/2026 to Midnight 9/07/2026
The cold southerly flow continues to bring rain and showers to parts of the North Island east coast. There is a low risk of thunderstorms from northern Hawke's Bay to East Cape. Elsewhere over New Zealand, 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.
