Heavy rain and thunderstorm warnings have been issued for Northland with up to 120mm of rain and thunderstorms possible across the region today and into tomorrow.
MetService said a low just north of Northland and an intense ridge of high pressure were expected to direct a strong moist southeasterly flow across the north of New Zealand during today.
The heaviest rain is expected to affect the eastern hills of Northland, with 80 to 120mm of rain possible between 1am this morning and 1am tomorrow.
People should also be aware of the risk of flash flooding since there is a possibility of localised thundery downpours when hourly rainfall rates could reach 25mm to 40mm.
Peak intensities of 25mm to 40mm per hour may be accompanied by thunderstorms. That level of rain could also lead to surface flooding.
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 Get Thru website
People can stay up to date with the latest weather forecasts, and any weather warnings or watches, at http://www.metservice.com.