Severe thunderstorm watch for Northland upgraded to a warning for Whangārei, Kaipara

More flooding could be on the cards for Northland today with MetService issuing a severe thunderstorm watch for the region. Photo / Michael Cunningham

MetService has detected severe thunderstorms near Whangārei and parts of Kaipara and issued a warning.

Severe thunderstorms were detected near Whangārei, Portland and Maungakaramea and were moving north, through Maungatapere, Kamo and Hikurangi.

Further thunderstorms were detected further south, near Kaiwaka and Brynderwyn.

The thunderstorms were expected to be accompanied by very heavy rain, potentially leading to surface and flash flooding. A severe thunderstorm watch for the Northland region was issued earlier today and expires at 9pm.

Northland, like much of the rest of the country, has been left soaked, with flooding and slips caused firstly by Cyclone Gabrielle and then by heavy rain on Friday.

MetService has issued a severe thunderstorm watch for Northland, Auckland, Waikato, Waitomo, Taumarunui, Bay of Plenty, Rotorua, Taupo, Hawke’s Bay, Taihape, Wanganui, Manawatu for that eight-hour period.

It said there is a moderate risk of thunderstorms for many parts of the North Island this afternoon and evening. These thunderstorms could bring localised heavy rain and hail.

The thunderstorms are expected to be slow-moving, and consequently there is a moderate risk that these storms could become severe, generating localised downpours of 25 to 40mm per hour, or possibly more.

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.

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.

The rain could cause even more problems for Northland’s storm-damaged infrastructure, which is reeling from damage from two major weather events in the past three weeks.

Last Friday’s deluge dumped up to 370mm of rain on parts of Northland in 24 hours.