WeatherWatch.co.nz's Philip Duncan is also forecasting rain for Northland, Hawke's Bay and Gisborne, with a minimum of 20mm set to fall in some areas.
He said it would be the first significant rain this year for all three regions.
"In fact it's the first time in a number of months," he said.
The Government last week officially declared Northland was in drought.
WeatherWatch.co.nz said Gisborne and Hawke's Bay also had drought conditions.
"But the rain expected this week will likely linger in the Gisborne area in particular," Mr Duncan said.
"Gisborne, western Bay of Plenty, eastern Coromandel Peninsula and eastern Northland are all candidates for rain this week.
"As for totals - they will be incredibly varied due to the patchy nature of the rain clouds plus our large mountains/ranges - but we may be seeing 20 to 40mm of rain falling in a number of areas. Gisborne city may receive 30 to 40mm."
Mr Duncan said the rain set to fall in Northland wouldn't be enough to reverse the drought, however it would put more of a dent in dry conditions in Gisborne.
"Hawke's Bay, being on the fringes, may be disappointed with how much falls - but there is still potential for some heavier downpours, especially in the north of the region."
Mr Duncan said Hawke's Bay and Wairarapa will get a mix of drizzle and downpours overnight tonight which are likely to intensify as the rain clouds move into the Gisborne area. The Coromandel will also get a smattering of rain.
"It's an unusual set-up with a wet southeast flow across the upper North Island for Thursday."