In a series of downpours, more than 14mm of rain was recorded at Ballarat Airport up to 10pm last night.

But the Bacchus Marsh Village Shopping Centre had to be evacuated yesterday afternoon when a large stretch of ceiling collapsed under the force of heavy rainfall.

Bacchus Marsh police Acting Sergeant Kevin Dans said a piece of ceiling measuring approximately 25 metres by 5 metres collapsed inside the centre about 2.45pm, forcing the centre to close for the remainder of the afternoon.

"Due to a large amount of rain received in a short space of time, a section of plaster roof has fallen and a number of stores within the complex ended up with flooding," he said.

"As a precautionary measure, the building was closed.

"There were numerous people in the complex but fortunately no one in the vicinity at the time."

Morning heat gave way to thunderstorms and rain yesterday afternoon, with the first storms moving across the district from about 2pm.

In the hour to 3pm, about 7mm fell at Ballarat Airport.

Fluctuating temperatures and winds reflected the unsettled conditions.

The mercury hit 33.6C at Ballarat Airport at 1.30pm, but by 3pm, it had dropped to 20.5C. The temperature rebounded to 25C an hour later, but dropped again when more rain arrived.

Northerly winds in the morning switched to the south-west by mid afternoon, and later came from the east.

More storms and showers are expected in the city today, with a top temperature of 27C. Showers and temperatures in the low 20s have been forecast for tomorrow, Saturday and Sunday.