Thunderstorm Outlook
Issued at 7:09am 28/10/2026
Valid from 7:09am 28/10/2026 to 1:00am 29/10/2026
A weak front affects the North Island during the second half of Wednesday, bringing periods of rain or showers, mainly to central and northern areas. There is a low risk of thunderstorms for Waikato, Waitomo, Taumarunui, Taihape, Taranaki and Whanganui, which then spreads into Auckland and Northland from evening. A front moves northeast over the lower South Island from late afternoon, bringing rain and there is a low risk of thunderstorms for Fiordland as indicated on the chart. There is minimal risk of thunderstorms or significant convection elsewhere during this period.
Issued at 8:55am 28/10/2026
Valid from 1:00am 29/10/2026 to 1:00pm 29/10/2026
A front moves north over central New Zealand bringing rain and increasing instability. There is a low risk of thunderstorms associated with the front in Buller, the far west of Nelson, Kapiti, Wellington and the far south of Wairarapa from around mid morning. These storms may be accompanied by heavy rain, 10 to 15 mm/h and there is a risk of small localised tornadoes near the front. There is minimal risk of thunderstorms or significant convection elsewhere during this period.
Issued at 7:11pm 28/10/2026
Valid from 1:00pm 29/10/2026 to 1:00am 30/10/2026
A front moves northeast over the North Island during the second half of Thursday bringing a period of rain. The front is followed by a cold unstable showery air mass. During the afternoon and evening, there is a moderate risk of thunderstorms about Canterbury from the foothills eastward, the Kaikoura Coast and Wairarapa. These storms may be accompanied by hail and bursts of heavy rain 10 to 15 mm/h. A low risk of thunderstorms extends further inland for Marlborough and Canterbury, also covering eastern Otago, Southland, Fiordland, coastal Westland, Grey and Buller as indicated on the chart. For the North Island from Waikato, Taupo and Hawke's Bay southwards, there is a low risk of thunderstorms in the afternoon and into the evening as indicated on the chart, along with a low risk of a localised small tornado associated with the front in the west. There is minimal risk of thunderstorms or significant convection 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.
