A front embedded in a northwest flow moves northeastwards over the North Island this afternoon. It is later followed by a second front, which brings a southwest wind change. Over the North Island, there is mostly a low risk of thunderstorms, as depicted on the chart. For Gisborne/Tairawhiti, Hawke's Bay, Manawatu, inland Whanganui, eastern Taranaki, Taihape, Taumarunui, southern Taupo, and the ranges of eastern Bay of Plenty, the risk is moderate this afternoon and evening. Any thunderstorms that occur will likely be accompanied by heavy rain with intensities of 10 to 20 mm/h. Hail 5 to 15 mm in diameter is also possible. Over the South Island, daytime heating and wind convergence is expected to cause showers to develop about Marlborough and Nelson/Tasman, and there is mostly a low risk of thunderstorms from late morning until this evening. For Tasman and inland Nelson, the risk of thunderstorms is moderate this afternoon. Any thunderstorms that occur will likely be accompanied by heavy rain with intensities of 10 to 20 mm/h. Hail 5 to 15 mm in diameter is also possible. There is minimal risk of thunderstorms or significant convection elsewhere in New Zealand during this period.

Chart reviewed at 8:10pm Tuesday and no changes made. A front preceded by a moist northwest flow moves over Fiordland during the morning. There is a moderate risk of thunderstorms for Fiordland after dawn, and a low risk from a few hours prior to dawn, which later in the morning extends southwards to include Stewart Island and northwards to include Haast. Any thunderstorms that occur will likely be accompanied by heavy rain with intensities of 10 to 20 mm/h, and possibly small hail. There is minimal risk of thunderstorms or significant convection elsewhere in New Zealand during Wednesday morning.

Chart reviewed at 8:10pm Tuesday and minor changes made. A front weakens as it moves up the West Coast during the latter half of Wednesday, while an unstable northwest flow persists over the deep south. There is a low risk of thunderstorms for most of Fiordland and Stewart Island in the evening and at night. There is also a low risk of thunderstorms for northern Fiordland and Westland south of the glaciers during the afternoon, and from the glaciers northwards to Buller during the afternoon and evening. Meanwhile, daytime sea breezes are expected to cause isolated showers to develop near the east coast from Dunedin to Marlborough, and there is a low risk of thunderstorms during the afternoon, as depicted on the chart. There is minimal risk of thunderstorms or significant convection elsewhere in New Zealand during this period.