People across the region experienced warmer temperatures with Whangārei airport sitting at 19.5C overnight, despite average overnight temperatures in April sitting around 13C.
Ferris said there was a moderate chance of the heavy rain watch upgrading to a warning.
He said where the rain would hit hardest depended on the wind direction but northern and eastern areas were likely to be more at risk.
Ferris warned that heavy rain saturating dry ground could bring about the risk of flooding and slips, he said.
Northland tipped into drought in early March for the eighth time in the last 20 years.
It marked a time of stress for farmers as feed shortages hit and water availability plummeted.
The region was also placed under a total fire ban following multiple large fires, such as the Waipoua River Fire which burned out of control through 100ha of pine and scrub.
While rain is expected to be the main threat over the coming days, the weather system would also bring breezier weather, Ferris said.
He encouraged motorists to take care on the roads during their morning commute on Friday
Temperatures were expected to stay high overnight into Friday but it would likely drop over the weekend.
Saturday looked to clear up; however, Sunday could bring more rain.
Brodie Stone covers crime and emergency for the Northern Advocate. She has spent most of her life in Whangārei and is passionate about delving into issues that matter to Northlanders and beyond.