MetService meteorologist Georgina Griffiths is warning of high intensity rainfall in areas north of Auckland city overnight.
"It's serious," she told Checkpoint. The key danger is soil is already saturated, she said.
"The region is just set up ... to flood quickly.
"What we expect is as soon as we get the high intensities on those saturated soils, we will see quick flooding and slips happening."
South of Orewa, Griffiths is saying there'll be possible localised flooding.
She said she has not seen rain like Friday's downpour in Auckland before.
"The combination of broadscale rain followed by near record rainfall in that one hour... the widespreadness of those downpours, I've not seen that in my forecasting career."
