It was a different story in the South Island with a mainly fine day in store for most, save a few showers in the far south.
Ms Flynn said Christchurch and Dunedin would enjoy a brisk but fine 16C day.
Earlier, MetService lifted a thunderstorm watch that it had issued this morning for northern regions of the North Island. The warning covered Auckland, Coromandel Peninsula, Waikato and Bay of Plenty.
Duty forecaster Claire Flynn said heavy showers were now over the Coromandel Peninsula but lightning activity had stopped.
The rain was expected to move off to sea.
MetService warned to expect intense localised downpours of up to 30mm in an hour as the stormy weather passes overhead.
It predicted possible surface and flash flooding, especially in low-lying areas such as streams, rivers or narrow valleys, and slips.
MetService said the front had already produced up to 30mm of rain in some places.