Weather: Northern NZ set for a drenching

File photo / NZ Herald

The top of the North Island looks set for a drenching to finish off the week, forecasters say.

On Thursday a front from the South Island will move northwards, followed by a cooler southerly flow that will spark a quickly forming low pressure system over Auckland and Northland, WeatherWatch.co.nz head analyst Philip Duncan said.

The system should prompt a band of rain stretching from the west to the east.

"To the north, around northern Northland we'll have sub-tropical northerlies.

"To the south, around Waikato and beyond, we'll have cooler southern ocean air," he said.

There was a low risk of thunderstorms and gales and a low to medium risk for flooding downpours in localised areas.

Heavy rain, thunder and gales were all possible at the lower end of the scale in localised pockets around the northern North Island, including Auckland, northern Coromandel Peninsula, Northland, from Thursday evening to Saturday at this early stage, he said.