Thunderstorm Outlook
Issued at 11:41am 7/06/2026
Valid from 11:41am 7/06/2026 to Midnight 7/06/2026
A showery southwest flow covers New Zealand today. As indicated on the chart, there is a low risk of thunderstorms about coastal parts of Hawke's Bay this morning, and about the fiords north of Doubtful sound until mid-afternoon. There is minimal risk of thunderstorms or significant convection elsewhere in New Zealand today.
Issued at 7:24pm 7/06/2026
Valid from Midnight 7/06/2026 to Midday 8/06/2026
Reviewed at 7:25pm Sunday - no changes. A front embedded in a strong west to southwest flow is forecast to move over southern New Zealand during Monday morning. There is a low risk of thunderstorms about the fiords, Stewart Island, and coastal parts of Southland and Clutha, as depicted on the chart. There is minimal risk of thunderstorms or significant convection elsewhere in New Zealand during Monday morning.
Issued at 9:04am 7/06/2026
Valid from Midday 8/06/2026 to Midnight 8/06/2026
The front continues to move northwards over central New Zealand during the latter half of Monday, and is followed by a cold and showery southwest flow. There is a low risk of thunderstorms for Stewart Island, and coastal parts of Clutha and Southland east of Riverton, as drawn on the chart. Also, although not shown on the chart, there is a low risk of thunderstorms for the Chatham Islands from afternoon. There is minimal risk of thunderstorms or significant convection elsewhere in New Zealand 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.
