MetService has issued a Severe Thunderstorm Watch on Sunday afternoon for Bay of Plenty, Coromandel Peninsula, Northland and Great Barrier Island.

An unstable northwest airflow lies over the northern North Island.

There is a moderate risk of thunderstorms about the Coromandel Peninsula overnight tonight for four hours from 11pm Sunday, June 16, to 3am, Monday, June 17. 

There is a moderate risk of thunderstorms about Bay of Plenty early Monday morning for five hours from 1am - 6am, Monday, June 17. Conditions are likely to ease in the west earlier than the east.

There is a moderate risk of thunderstorms for Northland this evening from 6pm until 12am, Monday, June 17. Conditions should start easing in the north after 10pm.

There is a moderate risk of thunderstorms about Auckland, including Great Barrier Island, for five hours from mid-evening around 9pm Sunday, June 16 until early tomorrow morning at about 2am.

Areas about and near the Hauraki Gulf are most likely to experience the downpours, but they may also occur elsewhere in Auckland.

Whether these thunderstorms occur or not, there is a chance of localised downpours of 25 to 40 mm per hour.

Rainfall of this intensity can cause surface and/or flash flooding, especially about low-lying areas such as streams, rivers or narrow valleys, and may also lead to slips.
Driving conditions will also be hazardous with surface flooding and poor visibility in heavy rain.

Note: A Severe Thunderstorm Watch means conditions are favourable for severe thunderstorms in and close to the watch area. People in these areas should be on the lookout for threatening weather conditions and monitor for possible Severe Thunderstorm Warnings.

For information on preparing for and keeping safe during a storm, see the Civil Defence Get Ready website