Issued at 8:44am 27/10/2025
Valid from 8:44am 27/10/2025 to 1:00am 28/10/2025
A deepening low will move across the South Island during the afternoon and evening, while a strengthening northwesterly flow with embedded fronts affects northern and central New Zealand. Severe Weather Warnings and Watches for strong wind, heavy rain and heavy snow have been issued for many parts of central and southern New Zealand. For more detail see https://www.metservice.com/warnings/home. Over the northern and central South Island, there is a broad low risk of thunderstorms embedded within broader areas of rain from Marlborough to inland Canterbury and northern Westland during the afternoon and evening as indicated on the chart. Areas of heavy rain are likely, whether or not thunderstorms occur. For Westland north of Hokitika, the Buller and Grey Districts, inland areas of Tasman, as well as western Marlborough and the headwaters of the Canterbury lakes and rivers north of Lake Coleridge, the risk of thunderstorms is moderate for a time during the afternoon and early evening. These thunderstorms may bring localised heavy rain with intensities of 10 to 20 mm per hour and strong wind gusts of 80 to 100 km/h. Over the North Island, there is a moderate risk of a few thunderstorms embedded within areas of rain in the west from Auckland to northern Wellington from evening (from Taranaki from late afternoon) as depicted on the charts, but the risk is considered high for Northland where there is also a low risk of localised downpours overnight with rain intensities of 25 to 40 mm/h. A low risk of thunderstorms covers areas further east at night as indicated on the chart. Any thunderstorms that occur will boost local rainfall rates to 10-25mm/h (or possibly higher). These thunderstorms will also be embedded with a strong northwest flow, but are expected to be elevated so shouldn't be squally. No other thunderstorms or significant convection expected over New Zealand during this period.

Issued at 7:59pm 27/10/2025
Valid from 1:00am 28/10/2025 to 1:00pm 28/10/2025
An active front over the upper North Island moves away to the east during the morning, while the deep low east of the South Island moves away to the southeast. A cold front moves onto central New Zealand from the west late morning. Severe Weather Warnings and Watches for strong wind, heavy rain and heavy snow have been issued for many parts of central and southern New Zealand. For more detail see https://www.metservice.com/warnings/home. There is a moderate risk of thunderstorms and LOCALISED DOWNPOURS of 25 to 40 mm/h from Northland to Waikato and across to Bay of Plenty before dawn, as well as strong wind gusts of 80 to 100 km/h. A SEVERE THUNDERSTORM WATCH is in force for these regions. A moderate risk of thunderstorms also extends from Waitomo to Taupo and southwards to northern Manawatu before dawn, with localised rainfall rates of 15 to 25 mm/h and strong wind gusts of 80 to 100 km/h. A broad low risk of thunderstorms covers much of the remaining North Island, also coastal parts of the South Island as depicted on the chart. No other thunderstorms or significant convection expected over New Zealand during this period.

Issued at 10:57am 27/10/2025
Valid from 1:00pm 28/10/2025 to 1:00am 29/10/2025
The cold front over central New Zealand moves away to the east during the second half of Tuesday, followed by a disturbed west to southwest flow across much of New Zealand. There is a moderate risk of thunderstorms for central areas of New Zealand from Waikato to Tongariro National Park, also Bay of Plenty, Gisborne/Tairawhiti and northern Hawke's Bay for a time in the afternoon. Any thunderstorms that occur could boost rain intensities to 10 to 20 mm/h. A low risk of thunderstorms covers a broad area of central and northern New Zealand as depicted on the chart during afternoon and evening, but the risk is considered moderate for Marlborough and Wairarapa including the Tararua range with rain intensities of 5 to 15 mm/hr and small hail. Another low risk of thunderstorms is for Fiordland and Stewart Island from evening. No other thunderstorms or significant convection expected over New Zealand during this period.

In New Zealand, MetService classifies a thunderstorm as severe if one or more of the following criteria are met:
Rainfall of 25mm/h, or more.
Hailstones 20mm in diameter, or larger.
Gusts of 110km/h (60 knots) or stronger.
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.