Thunderstorms and heavy rain are possible in Southland and inland Otago today.
A MetService spokesman said a warm moist and unstable northerly air mass would cover most of New Zealand today, with thunderstorms and/or heavy rain likely to affect many North Island and northern South Island areas.
He said it was possible the weather system may also affect the lower South Island as well.
Severe weather warnings and watches are in force for parts of the North Island and Tasman region today, with a risk of hail and localised downpours of more than 40mm per hour, especially about southern Northland, Auckland and Waikato this afternoon and evening, and about Bay of Plenty, Rotorua, Taupo and far northern parts of the Gisborne region at times during the day.
Local councils in these areas are on standby for surface or flash flooding about low-lying areas.
In the South Island, it was likely there would be isolated thunderstorms about Nelson, the Marlborough Sounds, and inland parts of Buller and northern Westland, bringing up to 25mm or more of rain per hour and small hail.
It was possible the weather system could spread to the south coast of Southland.
