As Aucklanders clean up from the wild weather, parts of Bay of Plenty and Gisborne may be next in the firing line.
The scene at an Auckland intersection yesterday. Photo: RNZ
MetService has a heavy rain watch in place for East Cape and Bay of Plenty today.
A second low tomorrow could bring extreme rainfall in Bay of Plenty and Tolaga Bay, with MetService saying it "has the potential to cause significant flooding".
Less severe but still heavy falls are possible for the rest of Gisborne, Hawke's Bay and the Tararua District.
MetService meteorologist Lewis Ferris told Morning Report that the heavy rain watches in place may be upgraded to orange or even red.
A decision will be made later today once regional councils have been consulted.
Of most concern are central to eastern parts of Bay of Plenty and northern parts of Gisborne, he said.
Meanwhile, Aucklanders are still cleaning up after a severe thunderstorm swept through the region yesterday.
More than a month's worth of rain fell, causing widespread flooding and road closures.
Niwa said Tāmaki Makarau experienced its second wettest hour on record and there were more than 9000 lightning strikes across the top of the North Island.
Auckland Council said its teams responded to around 40 critical requests for service relating to downed trees, and over 400 relating to flooding incidents on public land.
Ferris said the rain was torrential with many areas receiving 40 millimetres of rain in an hour so it was not surprising it led to flash flooding.
"It is much much harder for it to drain away" MetService meteorologist Lewis Ferris
He said it was "a little bit of a different beast" from the floods that hit Westport last month.
"The same sort of a driver - very moist air coming down from the subtropics which is what brings all that fuel and ability to get these very heavy intensity rainfall events happening very quickly."
The rain fell over a period of two days in Westport, but with Auckland's population density and the contours of the land, it can get dramatic effects with just an hour of rain.
On the West Coast 40 millimetres of rain in an hour will drain away to the sea.
"Seeing that in Auckland where there is not so much ability to run off and there's quite a lot of water surrounding the city itself, it is easy for that water to fall, it is much much harder for it to drain away."
Auckland mops up from yesterday's torrential rain