Unstable weather conditions could lead to thunderstorms over New Zealand today as another front moves over the country.
A severe weather watch has been issued for strong winds over parts of central and southern New Zealand, while bouts of heavy rain will hit the West Coast and lower South Island.
"Strong wind watches and warnings have been issued for Tuesday for parts of the east coast of the South Island (particularly Canterbury High Country) and the lower North Island ahead of the front," MetService warns.
"Here we have the thunderstorm risk for today. Moderate risks for Northland, Auckland, Buller, Westland, Fiordland and Stewart Island."
NIWA's weather animation shows an "intense low pressure system" south of Stewart Island, creating eight to 10-metre waves.
Weather Watch warns the biggest cold snap of the week will strike tonight, spreading as far north as the central North Island.