Thunderstorms bringing heavy downpours, hail and a small chance of a tornado in Auckland could be arriving within the hour.
The first band of isolated thunderstorms is moving into western Waikato and Auckland region from the Tasman Sea.
MetService meteorologist Tom Adams said the thunderstorms would bring heavy downpours to some areas, but won't be felt in other areas.
"It's a very bubbly convection system," he said.
WeatherWatch analyst Philip Duncan said the thunderstorms would be noticed around Auckland and Hamilton between 9.30am and 11am.