Heavy rain may cause surface flooding, slips and a rapid rise of water levels in streams and rivers in Northland, Auckland and Waikato tomorrow, MetService warns.
A front is forecast to slide north across central and northern New Zealand tonight, bringing a shift in the weather for many parts ofthe country.
Heavy rain is predicted to hit northern and western areas with the possibility of heavy snow falling on parts of the Gisborne and Hawkes Bay ranges.
MetService warned Auckland commuters to be aware of a heavy rain watch from 6am to 6pm tomorrow which could affect driving conditions.
Northland, Waikato and Taupo are also expected to be doused in rain tomorrow.
MetService has issued a number of weather warnings. Photo / Michael Craig
"The watch for heavy rain has now been upgraded to a warning and the area has now been extended to include Great Barrier Island," the weather service said.
"Expect 60mm to 80mm to accumulate." It predicted peak intensities of 25mm to 35mm/hr in localised downpours.
However, the rain isn't set to be much of a reprieve for Auckland's water supply, which is under pressure due to a dry six months to start the year.
Between 50mm and 80mm of rain is likely to fall on Thursday in the Hūnua and Waitākere ranges dam catchment areas, Watercare spokeswoman Maxine Clayton said.
"This is the only significant rainfall forecast for the whole month of July.
"Typically we see somewhere in range of 200mm during July, so potentially we're looking for a rain deficit of 250-375mm since January."
