Heavy rains coming in a week

Image / ECMWF

A sub-tropical low is heading towards the upper North Island in seven days time, says WeatherWatch.co.nz.

"For the next few months New Zealand remains at a heightened risk of lows from the tropics and sub-tropics due to La Nina creating warmer seas to our north west. Warmer waters fuel more lows.

For the past three days various reliable computer models have been picking an area of low pressure forming east of Cairns then drifting over the Coral Sea where it will intensify.

While not as intense as tropical cyclones, sub-tropical lows can sometimes pack a similar punch when it comes to rainfall. Major coastal flooding in Auckland in January, which occurred at the same as a King Tide, was caused by a sub-tropical low.

This next sub-tropical low looks likely to arrive in the upper North Island on either Monday April 11th or Tuesday April 12th. It will not coincide with a king tide, which next fall on April 19th and 20th, so coastal flooding won't be a major concern.

However sub-tropical lows are often rich in moisture and flooding rains are fairly common in regions such as Northland, Coromandel Peninsula, Bay of Plenty and East Cape.

As with any long range models there are high levels of uncertainty so we'll keep you posted on this potential system."

Tracking the potential low:

Midnight Saturday April 9

Midnight Sunday April 10

Midnight Monday April 11

- WeatherWatch.co.nz