Issued at 4:40pm 19/04/2026

Valid from 4:40pm 19/04/2026 to Midnight 19/04/2026

Update at 4:30pm, to extend the MODERATE risk of SEVERE thunderstorms in Auckland and Waikato down into Waitomo and northern Taumarunui, and take it out of Northland. Atmospheric conditions are quite unstable over much of the North Island and for parts of the South Island today. A slow moving front lies over eastern Bay of Plenty and northern Gisborne/Tairawhiti for much of today and there is a moderate risk of thunderstorms with heavy rain of 10 to 25 mm/h, as well as a low risk of downpours of 25 to 40 mm/h. During this afternoon and evening, a trough is expected to move over western parts of the North Island, bringing heavy showers to many places. There is a moderate to high risk of thunderstorms from Northland to Whanganui, with heavy rain of 10 to 25 mm/h and hail 10 to 20 mm in diameter and strong wind gusts of 90 km/h. A MODERATE risk of SEVERE thunderstorms for Waikato, Waitomo and northern Taumarunui which could bring localised downpours of 25 to 40 mm/h, and a LOW risk of SEVERE thunderstorms farther south to Whanganui, and also returning to Northland tonight. A larger low risk area extends over remainder of the North Island, and extending down over the upper South Island and the west coast to southern Westland as indicated on the chart. There is another low risk of thunderstorms for mid and southern Canterbury this afternoon and evening. There is minimal risk of thunderstorms or significant convection elsewhere during this period.

Issued at 8:11pm 19/04/2026

Valid from Midnight 19/04/2026 to Midday 20/04/2026

Conditions continue to be unstable over much of the North Island for first half of Monday as several rain bands move across the island bringing periods of heavy showers. There is a moderate risk of thunderstorms for the upper North Island during the morning with rain intensities of 10 to 25 mm/h and hail 10 to 20mm in diameter, as well as a low risk of SEVERE thunderstorms which could bring localised downpours of 25 to 40 mm/h. There is also a moderate risk for the western areas of Waikato and Waitomo, also northern Taranaki and for Gisborne/Tairawhiti and Hawke's Bay in the morning as depicted on the chart. In addition, there is a low risk of SEVERE thunderstorms for western Waikato and Waitomo, also northern Taranaki which could bring localised downpours of 25 to 40 mm/h. A broad low risk of thunderstorms covers remainder of the North Island, northwest Tasman and the Marlborough Sounds as indicated on the chart. From late morning, there is a low risk of localised downpours for Horowhenua Kapiti Coast, Wellington, Wairarapa and Marlborough Sounds with rain intensities of 25 to 40 mm/h. There is minimal risk of thunderstorms or significant convection elsewhere during this period.

Issued at 10:26pm 19/04/2026

Valid from Midday 20/04/2026 to Midnight 20/04/2026

Conditions continue to be unstable over much of the North Island during the second half of Monday as several rain bands move across the Island, helped by the day time heating, are expected to produce periods of heavy showers. There is a moderate risk of thunderstorms for the upper and central North Island during the afternoon and evening, and for eastern Bay of Plenty and northern Gisborne/Tairawhiti continuing into the night, as depicted on the chart. There is also a moderate risk of thunderstorms for central and southern Gisborne/Tairawhiti and Hawke's Bay from evening onwards. These thunderstorms may produce rain with intensities of 10 to 25 mm/h and hail 10 to 20mm, and there is also a low risk of SEVERE thunderstorms with localised downpours of 25 to 40mm/h for upper and central parts of the island. A broad low risk of thunderstorms covers remainder of the North Island as indicated on the chart, but there is a moderate risk of localised downpours for Horowhenua Kapiti Coast, Wellington Wairarapa and the Tararua District throughout the period. There is minimal risk of thunderstorms or significant convection elsewhere during this period.