Thunderstorm Outlook
Issued at 7:26am 19/01/2026
Valid from 7:26am 19/01/2026 to 1:00am 20/01/2026
A moist unstable easterly flow affects the far north of New Zealand. For Northland there is a low risk of thunderstorms with heavy rain this afternoon. This evening and at night there is moderate risk of thunderstorms with heavy rain there, 10 to 25 mm/h. There is also a moderate risk of Severe thunderstorms with localised downpours bringing 25 to 40 mm/h or possibly more. No thunderstorms or significant convection is expected in other areas 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.
