Weatherwatch meteorologist David Sercombe said Adamstown was the hardest hit with 20 millimetres of rain falling in half an hour.

"That sort of rainfall is quite intense but we didn't see the predicted strong winds to go with it," he said.

"The storm developed over Wollemi National Park in the west and made its way east where it collided with another storm in the Lower Hunter about 4pm."

Hunter Region duty officer Mandy Haigh said the State Emergency Service had received 14 calls for assistance between Singleton and Lake Macquarie by 6pm.

"Most of those jobs were for leaky roofs or maintenance issues," she said. "There was so much force behind the rain the drains just couldn't cope."

Go-Lo was evacuated and several Hunter Street businesses closed as a wave of water washed down the mall.

Newcastle Regional Library foyer was flooded but the building did not need to be evacuated.

Save Our Figs spokeswoman Caity Raschke said the benefits of the 14 Laman Street figs, which were felled over the past week, had been revealed by nature.

Were you affected by storms? Send your photos to enesmith@theherald.com.au