A trough in the Tasman Sea and associated rain-bands are expected to move onto western parts of central and southern New Zealand late today. Severe Weather Watches and Warnings for heavy rain have been issued for northern and western parts of the South Island. As indicated on the chart, there are low risk of thunderstorms embedded within broader areas of rain about Fiordland from afternoon, about Westland and Buller from this evening, and about North Taranaki tonight. If any thunderstorms do occur they are probably more likely offshore and will boost local rainfall rates. No other thunderstorms or significant convection expected over New Zealand today.

A moist northerly flow will cover the North Island on Monday morning with embedded fronts bringing rain to many northern and western areas. A weak trough covers the South Island. In the North Island, there is a moderate risk of a few thunderstorms about northern Northland mid to late morning, and a low risk covering other parts of Northland and western areas from Waikato to Taranaki. In the South Island, there is a low risk of a few thunderstorms about western areas from Kahurangi National Park to northern Fiordland before dawn. Any thunderstorms that occur will be accompanied by localised heavy rain. No other thunderstorms or significant convection expected over New Zealand on Monday morning.

A moist northerly flow will continue to cover the North Island during the second half of Monday bringing rain or showers to many North Island areas. A front moves onto the South Island from the Tasman Sea during this period. Over the northern and central North Island, there is a broad low risk of thunderstorms from Whanganui, Taihape and eastern Bay of Plenty northwards through the whole period. Over the South Island, there is a moderate risk of thunderstorms about southern Westland and northern/central Fiordland from late afternoon or early evening, with brief heavy rain and small hail. A broader low risk covers other western areas south of Westport, including near the main divide of the the Southern Alps, through the whole period. No other thunderstorms or significant convection expected over New Zealand during this period.