Thunderstorm Outlook
Issued at 8:11am 17/06/2026
Valid from 8:11am 17/06/2026 to Midnight 17/06/2026
A front over the upper South Island moves north over the North Island today. There is a low risk of isolated thunderstorms for Buller, northwest Tasman and Horowhenua Kapiti Coast during the morning and from Kapiti Coast to Taranaki and western Waitomo during the afternoon, as indicated on the chart. There is minimal risk of thunderstorms or significant convection elsewhere during this time.
Issued at 8:14am 17/06/2026
Valid from Midnight 17/06/2026 to Midday 18/06/2026
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.
