If New Zealanders were concerned about water shortages it appears that problem will fast be out the door as yet another low, the fourth sub-tropical low in a matter of weeks, eyes up the country, reports WeatherWatch.co.nz.

A major rainstorm is today continuing to dump torrential rain north over Coromandel Peninsula, Bay of Plenty, East Cape and Canterbury.

18 Rain Warnings are currently in force – they can be found here.

Tomorrow the large low will move from the Tasman Sea across central New Zealand.  Head weather analyst Philip Duncan says the centre of the low is extremely large and means central areas will be relatively calm tomorrow.  “We often hear about conditions in the eye of the storm being calm and that is the case tomorrow.  The centre of this storm is calm and relatively rain free.  It will move over the lower North Island easing conditions there but bringing severe weather to both ends of the country”.

Mr Duncan says it’s a typical clockwise set up.  “In the north it will be western areas pounded by a gale westerly in the afternoon and heavy showers, many squally with thunderstorms while in the south it will be easterlies driving in torrential rain to Canterbury and Otago”.

He says thunderstorms in western areas between Taranaki and Northland, near the coast, may be severe in the afternoon.  “This is a set up we’ve seen many times before and comes with the usual risk of hail, gusts over 100km/h and a chance of isolated waterspouts and tornados”.

MetService is also predicting thunderstorms, saying there’s a “moderate risk” of “severe” thunderstorms about western Waikato and western Auckland tomorrow afternoon and a moderate risk of lower grade thunderstorms from Taranaki to Northland.

WeatherWatch.co.nz says that gale force winds will also affect the lower south west quadrant of the South Island during Wednesday.

However WeatherWatch.co.nz is now concerned about another low appearing in the computer models for the end of the week, predicting yet another burst of heavy rain for northern New Zealand.

“It’s likely to track over the North Island during Thursday and Friday then deepen further near East Cape into the weekend, driving in heavy rain to eastern areas” says Mr Duncan.  “Flooding and slips will certainly be possible especially following today’s deluge”.

MetService has today also showed concern about the 4th sub-tropical low, mentioning it in their Severe Weather Outlook with moderate confidence of rain warnings being issued for northern and north eastern parts of the North Island at the end of the week.