Thunderstorm Outlook
Issued at 8:00am 24/04/2026
Valid from 8:00am 24/04/2026 to Midnight 24/04/2026
Active trough is forecast to move slowly north over Northland during Friday. There is a moderate risk of thunderstorms for parts of northern Auckland and Great Barrier Island during Friday morning and afternoon, and for eastern Northland about and south of Bay of Islands throughout the day, which could bring rainfall intensities of 10 to 25 mm/h, as well as a moderate risk of SEVERE thunderstorms with rainfall rates of 25 to 40 mm/h. In addition, there is a low risk of thunderstorms and localised downpours (rainfall rates of 25 to 40 mm/h) which extends over surrounding parts of northern Auckland, and southern and central Northland, as indicated on the chart. Broad scale warnings and watches are also in force, and details can be found here: https://www.metservice.com/warnings/home There is minimal risk of thunderstorms or significant convection elsewhere.
Issued at 8:02pm 24/04/2026
Valid from Midnight 24/04/2026 to Midday 25/04/2026
The active trough moves northwards across Northland during the first half of Saturday. There is a low risk of thunderstorms for eastern areas of Northland, and also a low risk of localised downpours. No thunderstorms or significant convection expected elsewhere during this period.
Issued at 9:40am 24/04/2026
Valid from Midday 25/04/2026 to Midnight 25/04/2026
The active trough continues to move northwards across Northland during Saturday afternoon and evening. There is a low risk of thunderstorms, and also a low risk of localised downpours. No thunderstorms or significant convection expected elsewhere 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.
