Issued at 8:15am 26/01/2025

Valid from 8:15am 26/01/2025 to 1:00am 27/01/2025

A low pressure system continues eastwards across New Zealand this afternoon and evening, with unstable conditions across much of the country. There is a moderate risk of thunderstorms from Auckland to Taranaki and across into Bay of Plenty and Taupo this afternoon, then for Bay of Plenty and the far north of Gisborne/Tairawhiti this morning and early afternoon, and also for coastal Whanganui, Manawatu and Wairarapa, mostly during the afternoon. These thunderstorms may produce localised heavy rain of 10 to 25 mm/h, and for Bay of Plenty and northern Gisborne/Tairawhiti strong wind gusts of 100 km/h and a slight chance of a small tornado. A broad low risk of thunderstorms covers the remaining North Island as depicted on the chart. A front and wind convergence bring a moderate risk of thunderstorms to northern Westland, Grey, Buller, Tasman and Nelson Lakes during the afternoon, and a moderate risk of thunderstorms to Canterbury, mostly from the foothills eastwards to the coast. These thunderstorms may produce localised heavy rain of 10 to 25 mm/h and hail of 5 to 15 mm diameter. Note, for Canterbury there is also a moderate risk of SEVERE THUNDERSTORMS producing localised downpours of 25 to 40 mm/h and a SEVERE THUNDERSTORM WATCH will be issued this morning. A low risk of thunderstorms covers the remainder of Westland, Nelson, Marlborough, and the Canterbury High County to North Otago. Note, an unstable southwest flow covers the lower South Island from evening, and there is a moderate risk of thunderstorms over southern parts of Fiordland and Southland, including Stewart Island. These thunderstorms may produce brief heavy rain and small hail. No thunderstorms or significant convection expected elsewhere during this period.

Issued at 8:06pm 26/01/2025

Valid from 1:00am 27/01/2025 to 1:00pm 27/01/2025

An unstable southwest flow affects New Zealand during Monday morning, with cold temperatures in the upper atmosphere over the South Island and lower North Island. There is a low risk of thunderstorms over the lower South Island, Canterbury, coastal Marlborough, Buller, Wellington, Kapiti and Wairarapa, as depicted on the chart. The risk of thunderstorms is considered moderate however over southern parts of Fiordland, Southland and Clutha before dawn. These thunderstorms may produce brief heavy rain and small hail. Although not depicted on the chart, there is also a moderate risk of thunderstorms about the Chatham Islands from late morning. These thunderstorms may produce heavy rain of 10 to 20 mm/h. No thunderstorms or significant convection expected elsewhere during this period.

Issued at 9:23am 26/01/2025

Valid from 1:00pm 27/01/2025 to 1:00am 28/01/2025

The unstable southwest flow over central parts of New Zealand gradually eases through the period. There is a low risk of a few thunderstorms in the afternoon about Banks Peninsula, coastal Marlborough and the Sounds, and the lower North Island. No thunderstorms or significant convection expected elsewhere during this period.