A couple of weakening fronts will move onto the southern South Island today bringing periods of rain, showers and possible thunderstorms to the area. There is a moderate risk of a few thunderstorms embedded within broader areas of rain about Fiordland and Stewart Island this morning, then a continuing low risk about Fiordland and southern Westland this afternoon. These thunderstorms will boost local rainfall rates to 10-20 mm/h in Fiordland and 5-15 mm/h on Stewart Island. This afternoon and evening, there is a moderate risk of isolated thunderstorms about Dunedin, Clutha, and parts of Southland, and a surrounding low risk about other parts of Southland and Otago as indicated on the chart. These thunderstorms will produce brief heavy rain of 5-15 mm/h and small hail. There is a minimal risk of thunderstorms or significant convection over other parts of New Zealand today.

A warm front moves onto the northern North Island on Sunday morning. There is an associated low risk of one or two thunderstorms over Northland from late morning. There is minimal risk of any thunderstorms or severe convection over other parts of New Zealand on Sunday morning.

A front in the Tasman Sea moves quickly over the South Island during Sunday afternoon and onto the North Island in the evening. Over the North Island, there is a moderate risk of periods of thunderstorm activity about central and southern Northland through the whole period, about Taranaki and Horowhenua/Kapiti in the late afternoon and evening, and about other northern and western areas from northern Northland to Coromandel Peninsula and Manawatu in the evening or at night as indicated on the chart. A low risk of thunderstorms also affects the northern and western North Island in the afternoon, and Bay of Plenty, Rotorua, Taupo, Taihape and Wellington from evening. Any thunderstorms that occur will produce localised heavy rain of 10-25mm/h (or possibly more in one or two places). Over the South Island, there is a moderate risk of elevated thunderstorms embedded within broader areas of rain about southern Tasman, Buller, Grey, Westland and the Canterbury High Country near the main divide during the afternoon, and about other parts of Tasman/Nelson and northern/western Marlborough in the late afternoon and early evening. These thunderstorms will boost local rainfall rates into the 10-25mm/h range. A low risk covers areas further east and south into northern Fiordland as indicated on the chart. There is a minimal risk of thunderstorms or significant convection over other parts of New Zealand during this period.